Adapted from the Flora of North America Editorial Committee (1993)
The following description comes from the Flora of China Editorial Committee (2015): Perennials, strongly rhizomatous, shoots extravaginal. Culms wiry, compressed, erect, often geniculate at base, simple or sparsely tufted, 15Ð50(Ð60) cm tall, 1.5Ð2 mm wide, nodes compressed, 3Ð6, 2Ð5 exserted. Leaf sheaths compressed to keeled, smooth, uppermost closed for 1/10Ð1/5 of length, blades flat, 5Ð12 cm ? 1.4Ð4 mm, surfaces smooth or adaxially scabrid, ligule 1Ð3 mm, abaxially scabrid, truncate to obtuse. Panicle contracted or slightly open, erect, narrow, 4Ð11 ? 0.5Ð1(Ð3) cm, branches erect or steeply ascending, or eventually spreading, 1Ð3 per node, densely scabrid angled from base, longest 2Ð4 cm with spikelets moderately crowded from the base or in distal 2/3. Spikelets ovate-lanceolate, 3.5Ð5 mm, florets 2Ð4, glumes lanceolate, nearly equal, 2Ð3 mm, 3-veined, apex acute or thinly mucronate, keel scabrid, rachilla smooth or minutely bumpy, lemmas oblong, 2.3Ð3.5 mm, apex obtuse, keel shortly villous for 2/3 of length, marginal veins to 1/3, intermediate veins faint, areas between veins glabrous, callus sparsely webbed or glabrous, palea keels scabrid. Anthers 1.3Ð1.8 mm. Caryopses 1.5 mm long.
From DiTomaso et. al. (2013), Flora of North America Editorial Committee (2014)
The following description is from the Flora of Panama (2016);Shrub or tree, 1.5-10 (15) m tall, the trunk up to 10 cm in diameter. Leaves: petioles slender, terete, slightly enlarged at the apex, 1.8- 14 cm long, more or less densely covered with minute scales, stipules narrowly ovate, acuminate, ca 1 cm long, fugacious, blade ovate or sometimes ovate-triangular, infrequently oblong-ovate, the base truncate or truncate-subcordate or rounded or rounded-subcordate, the apex sometimes acute to generally gradually long-acuminate and with the acumen usually blunt and often inconspicuously mucronulate, entire-margined, 5.5-27 cm long and 3-18 cm wide, membranous to chartaceous, 5-palminerved, slightly discoloured, the upper surface usually more or less shining and glabrous or sparsely lepidote especially when young and along the veins, the lower surface dull, paler, more or less densely lepidote, and with the main veins and secondary veins prominent.;Panicles few- to many-flowered, the axes densely covered with minute, reddish-brown scales, the bracts and bracteoles squamiform and fugacious. Flowers with the pedicels up to 1 cm long, densely covered with minute, reddish-brown scales, sepals circular, cucullate, 7-9 mm in diam, densely lepidote outside, petals obovate, rounded at the apex, 20-33 mm long and 8-20 mm wide, white or pink, androecium ca 14-15 mm long, the filaments filiform, the anthers ca 1-1.5 mm long, ovary more or less globose to pyriform, densely to sparsely bristly, the style up to 15 mm long, slightly enlarged towards the apex, glabrous. Capsules very variable in shape, size, and indumentum, oblong-ovoid to ovoid to globose to + reniform to transversely ellipsoid, more or less flat- tended or not, rounded to acute or sometimes acuminate at the apex, 1.3-4.5 cm long and 1.3-4 cm broad, brown to flaming red, densely to sparsely covered with long or sometimes short, flexible spines, sometimes nearly smooth, seeds obovoid- angular, ca 5 mm long, the testa densely reddish-orange papillate.
The following description is from Flora of Panama (2016)
Tender perennial herb, suffruticose, to 90 cm tall. Petiole 3-4.5 cm, glabrous, leaf blade ovate to triangular-ovate, 2.5-7 ? 2-4.5 cm, glabrous, abaxially glandular, base truncate or ± rounded, margin serrate, apex acuminate. 2-6-flowered, in racemes to 20 cm, bracts ovate, red, enveloping flowers in bud, apex caudate-acuminate. Pedicel 4-7 mm, red glandular villous. Calyx red, campanulate, ca. 1.6 cm in flower, dilated to 2 cm after anthesis, red glandular, veins villous, 2-lipped to ca. 1/3 its length, upper lip triangular-ovate, 5-6 ? 10 mm, apex mucronate, lower lip slightly longer than upper, deeply 2-toothed, teeth triangular. Corolla scarlet, 4-4.2 cm, pubescent, tube slightly dilated at throat, upper lip straight, somewhat concave, oblong, 8-9 ? ca. 4 mm, lower lip shorter than upper. Filaments ca. 5 mm, connectives ca. 1.3 cm. Nutlets dark brown, ellipsoid, ca. 3.5 mm, apex irregularly pleated, margin (or midvein) narrowly winged. Flowers March-October [Flora of China Editorial Committee, 2014].
G. physocarpus is an upright, soft shrub 0.5 to 2 m tall with a fibrous rootstock. Young stems and inflorescences pubescent. Petiole approximately 1 cm;leaf blade narrowly lanceolate, 5-l0 ? 0.6-1.5 cm, adaxially sparsely pubescent, abaxially hairy along midvein, both ends tapering or acute. Branches are pale yellowish green and hollow. The leaves are light green, opposite, and narrowly oblong to lance-shaped. Flowers in pendulous clusters, corolla white, 1.4-2 cm in diameter;lobes ovate, 8-10 mm, reflexed, margin densely bearded. Corona lobes white, inner margin of hoodlike apex with 2, short, recurved or straight cusps, with a large adaxial nectary. In the centre of the flower is the corona, consisting of five pouched lobes that develop from the petals. The petals are white and the corona is suffused with pink or purple. The corona surrounds the stamens and carpels composed of ovary, style and stigma. The filaments of the stamens are fused to form a staminal column which encloses the female part. The female part consists of two free carpels, the tips of which are united and enlarged to form the style head. This is the yellowish, 5-lobed disc that can be seen at the centre of the flower. The anthers are fused to the style head. The pollen grains of each anther lobe are united to form two waxy masses known as pollinia or pollen sacs. Fruits are large spherical inflated follicles, 6-8 ? 2.5-5 cm, base oblique, apex rounded, beakless;pericarp with soft bristles or spines, minutely tomentose when young, glabrescent when ripe. Seeds ovate, approximately 5 mm;coma shining white, approximately 5 mm, each with a tuft of long silky hairs attached at one end (Notten, 2010;Flora of China Editorial Committee, 2014).
G. physocarpus was recorded growing as a weed in pastures and in crops such as sugarcane (Motooka et al., 2003;Flora of China, 2014). It is also an environmental weed affecting principally lowland dry forests, coastal forests and wetlands (DAISIE, 2014;PROTA;2014;USDA-ARS, 2014).
An erect or spreading annual, up to 1.5 m tall but generally shorter. Stems cylindrical or slightly ridged, densely clothed with long, fine, spreading, grey or reddish-brown pubescence. Stipules linear, setaceous, up to 1 cm long. Five to seven leaflets, occasionally nine, elliptical-oblong, up to 40 mm long and 25 mm wide, the terminal one rather longer than the lateral, pilose on both surfaces. Inflorescence a dense, many-flowered raceme, hirsute, 20 to 30 cm long, including a peduncle more than 25 mm long. Bracts linear-lanceolate, up to 25 mm long. Pedicels around 1 mm long, reflexed in fruit. Calyx stiff, brown and hirsute, about 4 mm long, divided almost to the base into linear, setaceous lobes. Corolla white pubescent outside, brick-red or rose inside. Pods straight, rather tetragonal, with well-developed sutures, 12 to 20 mm long about 2 mm wide, thickly hirsute, many of the hairs, especially the dorsal ones, usually brown. Six to nine seeds, cuboid, angular, strongly pitted (FAO, 2013). In China, flowers July-September and fruits between October and December (e Floras, 2013).
Description from Munir (1987), Flora of China Editorial Committee (2016) and Wagner et al. (1999)
The following description comes from Flora of China Editorial Committee (2014);M. arboreus is a small shrub, up to 1 m tall. Branchlets sparsely villous to glabrate, rarely glabrous. Stipule filiform, approximately 4 mm, usually caducous, petiole 2-5 cm, puberulent, leaf blade broadly cordate to ovate-cordate, usually 3-lobed, sometimes entire, 6-12 ? 2.5-10 cm, nearly glabrous or stellate pilose on both surfaces, basal veins 3 or 5, base broadly cuneate to nearly rounded or cordate, margin crenate, sometimes irregularly so, apex acuminate. Flowers solitary, axillary, pendulous, tube-shaped, slightly expanding only at top, 2.3-5 cm. Pedicel 3-15 mm, villous or puberulent. Epicalyx lobes spatulate, 8-15 mm, connate at base, hairy. Calyx campanulate, approximately 1 cm in diameter, lobes 5, slightly longer or shorter than bracteoles, hirsute. Petals 5, scarlet-red, 2.5 - 5 cm. Staminal column 5-7 cm, exceeding corolla tube. Style branches 10. Ripe fruit bright red, usually 3- or 4-seeded.
The following description is from Cook et al. (2005) and the Flora of China Editorial Committee (2017)
The following description is taken from Flora of China Editorial Committee (2015);C. sempervirens is a tree growing up to 30 m tall, bark grayish brown, shallowly fissured, branches ascending or horizontally spreading, branchlets not arranged in a plane, ultimate ones 4-angled, approximately 1 mm in diameter. Leaves in 4 ranks, densely appressed, dark green, not glaucous, 0.5-1 mm, ridged abaxially, without a conspicuous abaxial gland, apex obtuse or subacute. Pollen cones 4-8 mm. Seed cones yellowish gray when ripe, subglobose or ellipsoid, 2.5-4 ? 2-3 cm, cone scales 8-14, each fertile scale with 8-20 seeds.
A large tree, up to 12 m tall with very minutely puberulous to glabrous young shoots. Leaves with a stout, 2-5 cm long, glabrous, grooved petiole, lamina thick fiddle-shaped or pandurate, 15-30 cm long, 12-20 cm 9-10-costate at the cordate base, sinuate-entire, almost truncate and very shortly acuminate at the apex, glabrous, lateral nerves 4-5 pairs, bulging beneath intercostals present, stipules narrowly triangular-lanceolate, 4-5 cm long, acuminate, glabrous, persistent. Hypanthodia sessile, in axillary pairs, globose, 2.5-4.5 cm in diam., finely puberulous, subtended by 3 triangular, appressed basal bracts, apical orifice somewhat depressed, ± 2-lipped, closed by lanceolate inwardly directed bracts. Male flowers: sepals 2-3, ovate-lanceolate, stamen solitary with ovoid anther. Female flowers, sepals 3, ovate, obtuse, style short with papillate stigma. [from Flora of Pakistan, 2014]
P. campanulata is a small, deciduous, flowering tree that grows up to 8 m high (Flora of China Editorial Committee, 2018;NZFlora, 2018). It has characteristic deep red, bell-shaped flowers of up to 2.2 cm diameter that hang in clusters in late winter to early spring (GISD, 2011). Clusters contain 1-5 flowers on very short shoots which elongate after anthesis (NZFlora, 2018). Flowers can appear on the branches before leaves emerge (GISD, 2011). Sepals are triangular, 3-6 mm, magenta to dark red, glabrous, shiny becoming spreading or reflexed. There are five petals, 5-12 mm in diameter, corolla appearing campanulate and eventually spreading, broadly elliptic-ovate, deep pink to rose-magenta (NZFlora, 2018). Flowers have 39-41 stamens, and the style is hairy and usually longer than the stamens (Flora of China Editorial Committee, 2018). Filaments are flushed magenta to crimson. Fruits are ovoid, 12 x 10 mm, glabrous, glossy scarlet, with a smooth stone (NZFlora, 2018). Leaves are serrated, which is typical of other cherry species, 4-7 cm long and 2-3.5 cm wide, bright green on emergence, changing to dark green in summer and bronze in autumn (GISD, 2011). Leaf petioles are 12-20 mm and hairy, and blades obovate to broadly elliptical (NZFlora, 2018). The bark is blackish brown, branchlets are brown to purplish brown and young branchlets are green and hairy (Flora of China Editorial Committee, 2018).
The following description is from the Flora of Panama (2017)
The following description is from the Flora of Pakistan (2017)
B. aegyptiaca is a multi-branched, spiny shrub or tree up to l0 m high. Stem with a reticulate dark brown or grey (rarely green) bark;branches green or greyish, stiff and brittle, always armed with stout simple green or yellowish spines. Leaves petiolate;leaflets shortly petiolulate;lamina 2.5Ð6 ? 1.5Ð4 cm., slightly asymmetric, elliptic to elliptic-obovate, apex subacute to obtuse, sometimes slightly refuse, base cuneate or rarely rounded, coriaceous, puberulous when young, later glabrescent or sometimes remaining puberulous on the lower surface;secondary nerves 4Ð6 pairs, ± prominent beneath;petiole (0.5) 0.8Ð2 cm. long, puberulous or glabrescent, canaliculate. Flowers in usually few-flowered sessile or shortly pedunculate fascicles;pedicels up to 1á5 cm. long, ± densely greyish-pubescent. Flowers c. 1á4 cm. in diam. Sepals 5.2Ð7 ? 2.7Ð3á25 mm., ovate or ovate-lanceolate, coriaceous, caducous, densely pubescent outside, with long silky whitish hairs inside. Petals 7.2Ð9.5 ? 2Ð2.4 (2.8) mm., narrowly elliptic or elliptic-oblong, rarely lanceolate-oblong, glabrous on both surfaces. Stamens with the anthers 1.7Ð2.2 mm. long, ovate or ovate-oblong, glabrous;filaments c. 3.75 mm. long. Ovary densely covered with long silky hairs. Drupe yellowish or green, up to 5 ? 2.5 cm., usually subcylindric, more rarely narrowly ellipsoid or subobclavate, finely puberulous, sometimes glabrescent (Flora Zambesiaca, 2016).
E. ophiuroides is a perennial, stoloniferous, mat-forming grass. Culms decumbent, rooting and branching, flowering shoots 15-30 cm tall. Leaf sheaths keeled, overlapping at base, hairy at mouth;leaf blades flat, (1-)3-10 ? 0.2-0.4 cm, usually glabrous, apex obtuse;ligule 0.2-5 mm, margin ciliate. Raceme erect or slightly curved, 4-6 cm;rachis internodes narrowly oblong-clavate, glabrous, 2.5 mm. Sessile spikelet 3.5-4 mm;lower glume oblong, ± leathery, shiny, glabrous, 5-7-veined, marginal spines very inconspicuous, short along incurving lower keels or reduced to knobs, apex acute but appearing broadly truncate because of flanking membranous wings. Pedicelled spikelet vestigial or absent. Caryopsis about 2.0 mm long, narrowly elliptic (Flora of China Editorial Committee, 2016).
L. lucidum is an evergreen shrub or small tree 2-10 m tall (in some cases up to 25 m). The leaves are glaborous (i.e. hairless) and vary from ovate (egg-shaped) to elliptic in shape. Leaves are 6-17 long and 3-8 cm wide, leathery or papery with the base rounded or sometimes attenuate and the apex acute to acuminate or sometimes obtuse. Leaves have between 4 to 11 primary veins on each side of the mid-vein, slightly raised or obscure. Flowers are sessile or nearly so with four white or cream petals (calyx 1.5-2 mm, corolla 4-5 mm) that are fused at the base into a very short tube. Flowers have a sickly sweet fragrance. Flowers have two stamens approaching the apex of corolla lobes with anthers of 1-1.5 mm long and hold pyramidal panicles 8-20 cm long and 8-25 cm wide. Fruits are deep blue-black, ripening becomes red-black (7-10 ? 4-6 mm) (Nesom, 2009;Flora of China Editorial Committee, 2015).
L. japonicus is an annual or biennial herb. Taproots with dense, fibrous rootlets. Stems erect, 30-120 cm, retrorsely strigose, nodes and angles densely strigose. Petiole of stem leaves 0.5-3 cm, narrowly winged at apex;lower stem leaf blades ovate, base broadly cuneate, lobes oblong-rhombic to ovate, 2.5-6 ? 1.5-4 cm, pinnately divided, adaxially strigose, abaxially pilose, glandular;mid stem leaf blade rhombic, lobes oblong-linear, base narrow cuneate. Verticillasters 8-15-flowered, 2-2.5 cm in diameter;floral leaves subsessile, linear to linear-lanceolate, 3-12 ? 2-8 mm, entire or dentate;bracteoles spiny, shorter than calyx, approximately 5 mm. Flowers sessile. Calyx tubular-campanulate, 6-8 mm long, appressed puberulent;teeth broadly triangular, 2-3 mm long, apex spinescent. Corolla white or reddish to purplish red, 1-1.2 cm long, villous;tube approximately 6 mm, inconspicuously scaly annulate inside;upper lip straight, concave, oblong, approximately 7 ? 4 mm, margin entire, ciliate;lower lip slightly shorter, base sparsely scaly;middle lobe obcordate, base constricted, margin membranous, apex emarginate;lateral lobes ovate. Filaments sparsely scaly. Fruit a brownish, oblong, triquetrous nutlet, approximately 2.5 mm long, base cuneate, apex truncate, smooth (e Floras, 2014).
B. pilularis is an evergreen shrub, often 1-3 m in height (Steinberg, 2002);leaves are sessile or short petiolate with blades oblanceolate to obovate with three principal veins and in alternate leaf arrangement (Flora of North America Editorial Committee, 2015). There is a well-developed taproot of up to 3 m and lateral roots are also well developed (Steinberg, 2002). Inflorescences in paniculiform arrays (Flora of North America Editorial Committee, 2015) and made up of small whitish (female) to yellowish (male) flowers. Female flowers are discoid without ray florets (Steinberg, 2002). They are 0.4-0.63 cm long, and clustered at branch tips or in leaf axils. Male flowers are slightly smaller. Achenes are 0.1-0.2 cm long with a 0.6-1 cm long pappus (Munz, 1973;Hickman, 1993). Plants are dioecious with male plants flowering before the females. Achenes are small with long pappus. Seeds are very light (Steinberg, 2002).
K. blossfeldiana is a succulent plant with flat, glossy, green leaves. Stems are 40-50 cm. Leaf blades are elliptic to ovate or oblong-spatulate, 3-10 cm, margins crenate or almost entire, apex obtuse or nearly acute. Cymes are dense, compound, glabrous, not glandular. Pedicels are 0.5-2 cm. Flowers are fragrant;sepals ascending, triangular-lanceolate, 4-10 mm;corolla scarlet, cylindric, tube approximately 8 mm, lobes wide-spreading (Flora of North America Editorial Committee, 2016).
From Flora Zambesiaca (2013)
O. barthii is a major weed of rice in West Africa. It is apparently less serious in other parts of Africa, and not recorded as a significant weed in any other crops.
The following description is from Flora of North America Editorial Committee (2017)
The following description is from the Flora of China Editorial Committee (2016)
The following description is from Flora of North America Editorial Committee, 2015;Perennials, 6Ð65+ cm (usually rhizomatous, sometimes stoloniferous). Stems 1(Ð4), erect, simple or branched, densely lanate-tomentose to glabrate. Leaves petiolate (proximally) or sessile (distally, weakly clasping and gradually reduced), blades oblong or lanceolate, 3.5Ð35+ cm ? 5Ð35 mm, 1Ð2-pinnately lobed (ultimate lobes ± lanceolate, often arrayed in multiple planes), faces glabrate to sparsely tomentose or densely lanate. Heads 10Ð100+, in simple or compound, corymbiform arrays. Phyllaries 20Ð30 in ± 3 series, (light green, midribs dark green to yellowish, margins green to light or dark brown) ovate to lanceolate, abaxial faces tomentose. Receptacles convex, paleae lanceolate, 1.5Ð4 mm. Ray florets (3Ð)5Ð8, pistillate, fertile, corollas white or light pink to deep purple, laminae 1.5Ð3 ? 1.5Ð3 mm. Disc florets 10Ð20, corollas white to grayish white, 2Ð4.5 mm. Cypselae 1Ð2 mm (margins broadly winged).
The following description is taken from the Flora of North America Editorial Committee (2015). Plants annual to biennial. Stems trailing, dichotomously branched, to 1 m. Leaves sessile or petiolate, petiole, ± clasping, blade ovate to spatulate, flat, 2-20 cm, margins undulate. Inflorescences terminal or axillary, cymes, proximal bracts opposite, leaflike, distal bracts alternate, reduced, flowering profusely. Flowers 7-10 mm diam., hypanthium aging red, round, calyx lobes 5, unequal, petals 20-40, connate into tube, white, aging pink, stamens 30. Capsules coarsely papillate. Seeds 200, rough with minute tubercles.
Shrub, 1.5-3 m tall, laxly branched. Leaves verticillate, sessile, 3-5 in each whorl, narrowly lanceolate, 10-20 cm long, 1-2.5 cm broad, entire, acute. Cymes verticillately arranged to form a terminal, 20-25 cm long panicle. Flowers white, c. 1.5 cm across, bracts 5-10 mm long, reddish when young, linear to linear-lanceolate, pedicels up to 1.5 cm long. Calyx-lobes 6-7 mm long, ovate-lanceolate. Corolla-tube 8-10 mm long, glabrous, lobes ovate-oblong, 10-12 mm long, obtuse. Drupe c. 1 cm in diameter, bluish-black, enclosed by enlarged red coloured calyx [Flora of Pakistan, 2014].
The following description is taken from Flora of China Editorial Committee (2016)
From Remaley (2005), Flora of China Editorial Committee (2014), ISSG (2014) and PIER (2014)
The following description is from the Flora of China (Flora of China Editorial Committee, 2017)
The following description is from the Flora of Pakistan (2017)
Lianas woody, to 10 m. Stem brownish, lenticellate;young branchlets pubescent, glabrous when older. Petiole 3-12 mm long;leaf blade ovate to obovate or narrowly elliptic, 2-10 X 1-4.5 cm, papery, glabrous or sometimes sparsely pubescent abaxially. Cymes paniculate, terminal and axillary;peduncle 2-6 cm, puberulent to glabrous. Sepals narrowly oblong, 2-5 mm, spreading or reflexed, pubescent outside, ciliate, apex obtuse or acute. Corolla white, tube dilated at middle, 5-10 mm, throat glabrous or pilose facing stamens;lobes obovate, as long as tube. Stamens included, inserted at middle of corolla tube;ovary glabrous. Follicles linear, 10-25 cm X 3-10 mm. Seeds oblong, 1.5-2 cm, coma 1.5-4 cm (Flora of China Editorial Committee, 2017).
Shrubs or small trees, to 7 m tall. Branchlets slender, 4-angled or subulate, puberulous, glabrescent. Leaves sessile or with petiole to approximately 2 mm, leaf blade elliptic, oblong, obovate, or suborbicular, typically at least some suborbicular to obovate and mucronate, 2.5 Ð 7 ? 1.5 Ð 4 cm, papery to slightly leathery, glabrous or with slight indumentum on veins abaxially, lateral veins 3-7 pairs, base broadly cuneate to rounded, apex acute, obtuse with small mucro, or retuse. Panicles sub-pyramidal, 7 Ð 20 cm, puberulous, densely flowered. Floral tube 6-merous, 7Ð11 mm, smooth walled or obscurely to decidedly 6-ribbed, glabrous, sepals 3.5 Ð 5.5 mm, adaxially glabrous, annulus present, epicalyx absent. Petals purple, fuchsia, pink, or white, orbicular, 1.2-2 cm including claw 6-9 mm. Stamens 36 Ð 42, dimorphic. Ovary glabrous. Capsules ellipsoidal, 1Ð1.3 ? 0.7Ð1.2 cm, 4Ð6 valved. Seeds including wing approximately 8 mm (Flora of China Editorial Committee, 2014).
Large trees up to 20 m tall, young branches glabrous, with yellowish-brown to gray exfoliating epidermis. Elliptic to oblong leaves (6-) 12-30 cm long and 5-15 cm wide, acuminate at apex, rounded at base, glabrous, smooth, leathery, gray to brown when dry, petioles 2.5-5 cm long, glabrous, yellowish-brown to black, stipules (0.4-) 5-15 cm long, glabrous to ser’ceas. Two fruits per node, obovoid, 1-2 cm long, glabrous, green with dark spots, ostiole slightly conical, sessile, basal bracts fused and forming a domed base, wavy apically, 1.5-2.5 mm long, glabrous or sometimes puberulent. [Description from Flora of Nicaragua, 2014].
The following description is from Flora Mesoamericana (2018) and Flora of China Editorial Committee (2018)
Z. matrella grows as a low, rhizomatous, perennial grass. Prostrate culms grow 5 cm in height (Tsuruta et al. 2011) but sometimes to 35 cm long (FAO, 2015, Clayton et al., 2016). Leaves grow stiffly with the blades often curled, 3-8 cm long and 1.5-2.5 mm wide. The leaf sheaths are smooth with a membranous ligule and hairy throat (Flora of China Editorial Committee, 2016, Clayton et al., 2016). The inflorescences are terminal with spike-like racemes up to 4 cm long. Spikelets yellowish brown to purplish brown, 10-30, loosely overlapping. The lower glume is usually absent, the upper glume is lanceolate, 5-veined with a prominent midrib. The lemma is oblong-ovate, 2-2.5 mm and the palea is lanceolate, half as long as the lemma (Flora of China Editorial Committee, 2016).;Z. matrella var. pacifica is distinguished by, Òleaf-blades 0.7-1 mm wide, usually erect, peduncle not or hardly exerted from the uppermost sheath, the raceme therefore not or little exerted above the foliage, up to 1.5 cm long, distribution: Taiwan to the Ryukyu Islands and Loo Choo Island, Marianas, Solomons and in the MoluccasÓ (Ô FAO, 2015).
Deciduous tree, usually more than 10 m tall, sometimes to 30 m. Leaves 15-40 cm, leaflets 5-12 pairs, 2-8 ? 1.2-3.3 cm, both surfaces pilose or abaxially pilose, adaxially sparsely puberulent, base slightly asymmetric, apex acute, obtuse, or shortly acuminate. Inflorescence a raceme or panicle, terminal on leafy shoots or lateral on short side branches, up to 16 cm long, many-flowered, flowers with sepals 4-10 mm long, green to dark red, petals 15-35 mm long, whitish to reddish or buff, stamens 10, 3 longer ones with filaments 2 cm long, 4 shorter with filaments about 1 cm long and 3 reduced with filaments about 1 cm long and minute anthers. Fruit a pendent, terete legume, 20-60 cm long, 1-1.5(-2.5) cm in diameter, indehiscent. Seeds numerous, embedded in a flat disk, 6.5-8.9 mm long, 5.6-7.0 mm wide, and 2.5-5.5 mm thick (Orwa et al., 2009, Flora of China, 2014).
The following description is adapted from Flora of North America (2013).
B. asiatica is a large tree, 7 to 25 m tall, growing as a mangrove associate on sandy and rocky shores. Branches stout;bark fissured. Leaves sessile, obovate to obovate-oblong, 20-40 ? 10-20 cm, leathery, shiny, base cuneate, margin entire, apex obtuse or broadly rounded. Racemes mostly terminal, erect, 5-15 cm, 5-10(-20)-flowered;bracts ovate, 8-20 mm;bracteoles triangular, 1.5-5 mm. Pedicel 5-9 cm. Flower buds 2-4 cm in diam. Calyx undivided, rupturing at anthesis into 2 or 3 unequal, rounded or acuminate, persistent lobes 3-4 ? 2-3 cm and a tube 3-5 mm. Petals 4, white, ovate or elliptic, 5-6 cm. Stamens in 6 whorls;tube 1.5-6 mm;filaments and style white, red-tipped;outer filaments 7-9 cm. Ovary 4-loculed, 5-9 mm;ovules 4 or 5 per locule;style 11-13 cm. Fruit dispersed by floating, broadly pyramidal, smooth, 9-11 cm, apex tapering and crowned by calyx;pericarp spongy, fibrous, green at first than turning brown when ripe and floats on water. The middle layer is spongy (like the coconut) and contains air sacs to help the fruit float (Polunin, 1987;Flora of China Editorial Committee, 2014).
The following description comes from Flora of China Editorial Committee (2015);Trees or erect shrubs, 7-10 m tall. Bark grayish to dark brownish, thick, smooth, branches puberulent when young, later glabrous. Petiole 3-4 cm, leaf blade suborbicular, 10-15 ? 9-14 cm, stiffly papery, abaxially almost glabrous, adaxially glabrous, primary veins 9-11, secondary and higher order veins protruding, base shallowly cordate, apex bifid to 1/3-1/2, lobes slightly acute or rarely rounded at apex. Inflorescence a raceme with few flowers, or a panicle with up to 20 flowers, axillary or terminal. Flower buds fusiform, 4- or 5-ridged, with an obtuse apex. Pedicel 7-12 mm. Calyx open as a spathe into 2 lobes, one with 2 teeth and other 3-toothed. Petals light pink, oblan?ceolate, 4-5 cm, clawed. Fertile stamens 3, filaments ca. as long as petals. Staminodes 5 or 6, 6-10 mm. Ovary stalked, velvety, style curved, stigma slightly enlarged, peltate. Legume linear, flat, 12-25 ? 2-2.5 cm, valves woody. Seeds compressed, sub?orbicular, 12-15 mm in diameter.
The following description is from Flora of China Editorial Committee (2016)
M. jalapa is reported as being a weed in apple orchards (CONABIO, 2016). Its allelopathic effects can inhibit the germination and growth of wheat and cabbage (Xu et al., 2008).
The following description is from the Flora of China Editorial Committee (2017)
The following description is from Flora of China Editorial Committee (2016)
D. bicornis is an annual, sometimes perennial grass. It is listed as invasive in North America (Mexico), Central America (El Salvador, Guatemala, Honduras, Nicaragua, Panama), the Caribbean (Cuba), South America (Colombia, Ecuador) and Oceania (Nauru, USA-Hawaii) (Catasús Guerra, 2015;PIER, 2016). It is considered as a weed in cultivated fields (Quattrocchi, 2006;Dias et al., 2007;Duarte et al., 2009;Catasús Guerra, 2015;Ramírez S et al., 2015).
D. bicornis is a weed that occurs in maize, rice, soyabean and sugar cane fields (Quattrocchi, 2006;Dias et al., 2007;Ramírez S et al., 2015). Plants of maize and rice have been reported as being affected by downy mildew disease caused by Sclerophthora rayssiae that was acquired from soil where seedlings of D. bicornis were previously growing (Chamswarng et al., 1976).
C. spectabilis is an erect herb 0.6-1.5 m tall. Branches terete, glabrous. Stipules ovate-triangular, approximately 1 cm. Leaves simple;petiole 2-8 mm;leaf blade oblanceolate to narrowly elliptic, 7-15 × 2-5 cm, thin, abaxially appressed silky pubescent, adaxially glabrous, base broadly cuneate, apex obtuse and mucronate. Racemes terminal, 20-30-flowered;bracts ovate-triangular, 7-10 mm. Pedicel 1-1.5 cm;bracteoles inserted at or apical to middle of pedicel, linear, approximately 1 mm. Calyx 2-lipped, 1.2-1.5 cm, glabrous;lobes broadly lanceolate-triangular, longer than tube. Corolla pale yellow;standard veined purplish red, suborbicular to oblong, 1-2 cm, base with 2 appendages, apex obtuse to retuse;wings obovate, approximately 2 cm;keel rounded about middle, with a fairly short and slightly incurved twisted beak beyond calyx. Legume broadly oblong, 2.5-3 × 1.5-2 cm, 20-30-seeded, shortly stipitate, glabrous. Seeds smooth, dark brown, 4.5 mm long (Flora of China Editorial Committee, 2015).
C. spectabilis is native to tropical Asia and has been widely introduced in many tropical countries around the world. It has escaped from cultivation and can now be found naturalized principally in open and disturbed sites. This species is a serious weed in agricultural land and natural habitats (Randall, 2012). The potential invasiveness of C. spectabilis is very high mainly because this species spreads predominantly as a contaminant in agricultural equipment, crop seeds, forages and hay (Maddox et al., 2011). In the United States, it is listed as a noxious weed in many Mid-South states (e.g., Arkansas), and it has spread rapidly throughout the Southeastern states where it is now considered an invasive species (Maddox et al., 2011;USDA-NRCS, 2015). C. spectabilis is also listed as invasive in Cuba, Australia, New Caledonia and many other islands in the Pacific Ocean (Oviedo Prieto et al., 2012;PIER, 2015;Weeds of Australia, 2015).
C. spectabilis is a common weed in maize and soyabean plantations in the United States. It is also a weed in active and abandoned pastures (Maddox et al., 2011).
D. aegyptium is a grass, with characteristic 'bird's foot' digitate inflorescence, up to 50 cm tall.
Annual, never stoloniferous. Culms up to 50 cm tall, up to 5 noded, geniculately ascending, usually rooting from the lower nodes, thus giving the plants a pseudo-stoloniferous appearance, not rarely forming radiate mats, branched from the lower nodes;internodes cylindrical, glabrous, smooth, striate, exserted above, variable in length;nodes thickened and glabrous. Young shoots cylindrical or rounded. Leaf-sheaths keeled, up to 5 cm long, rather lax, striate, tuberculately hairy on the keel or quite glabrous;ligule membranous, about 1 mm long, ciliolate along the upper edge;leaf blades flat when mature, rolled when in bud, linear, tapering to a fine point, up to 20 cm long and 12 mm wide, with 3-5 primary nerves on either side of the midrib, glaucous, usually more or less densely tuberculately hairy along the margins and the keel, less conspicuously so on the adaxial surface towards the tip.
Inflorescence digitate, composed of 4-8 spreading spikes. Spikes 1.5-6 cm long, on maturity often somewhat recurved, greenish-yellow or pallid;rachis keeled, smooth near the base, scaberulous towards the apex, tip mucroniform and curved. Spikelets 4 mm long, strongly compressed, ovate, solitary, sessile, patent alternately left and right on the ventral side of the axis;dense, forming a very flat comb, usually 3-flowered;lower florets bisexual, the upper florets rudimentary;axis without terminal stipe. Lower glume 2 mm long and 2 mm wide, ovate in profile, 1-nerved, sharply keeled, keel scabrid;upper glume 2 mm long excluding the 1.5-2 mm-long awn, oblong in profile, 1-nerved, sharply keeled, keel scabrid. Rachilla slender. Lemmas 3-4 mm wide, the upper smaller in dimensions (but similar), folded about the keel which is scabrid, broadly ovate in profile, lateral nerves delicate and indistinct;uppermost lemma epaleate. Paleas about 3 mm long, 2-nerved, keels scabrid, dorsally concave, shortly bifid at the apex. Three anthers, pale-yellow, 0.3-0.5 mm long, anther cells somewhat remote, with a conspicuous connective. Caryopsis sub-triangular or sub-quadrate, laterally compressed, rugose, light-brown, apex truncate, never convex, remains of pericarp at times visible. (Fisher and Schweickerdt, 1941).
D. aegyptium is usually identified initially by the characteristic 'bird's foot' arrangement of the inflorescence with 4-8 spreading spikes. It is sometimes found as seed during inspections of seed samples.
Producing large quantities of seeds, D. aegyptium is a pioneer grass that quickly colonizes disturbed areas with light sandy soils, often near to coasts or where water accumulates. It is a common component of weed floras throughout the tropics but is rarely reported as an aggressive weed on its own. It is not on federal or state noxious weed lists in the USA and is not recorded on the ISSG database but is recorded by PIER (2016) as invasive on a number of Pacific and American islands including French Polynesia Islands, Micronesia, the Northern Mariana Islands and Hawaii. It is also listed as invasive on islands in the Mediterranean, the USA, Mexico, Costa Rica, Puerto Rico, Virgin Islands and the Lesser Antilles (Vibrans, 2009;Florida Exotic Pest Plant Council, 2011;Chacón and Saborío, 2012;Burg et al., 2012;Rojas-Sandoval and Acevedo-Rodríguez, 2015;DAISIE, 2016;USDA-NRCS, 2016).
D. aegyptium is a ubiquitous weed in many cropping systems around the world. Holm et al. (1977) classified the degree of importance of D. aegyptium on crops in different countries, in decreasing level of severity, as follows: a serious weed of cotton in Thailand;a principal weed of cotton in Australia, Kenya, Mozambique, Nigeria, Sudan, Tanzania, Uganda and USA, of sugarcane in India, the Philippines and Taiwan, of groundnuts in the Gambia and USA, of maize in Ghana and India and of rice in Sri Lanka and India;a common weed of rice in Indonesia, Nigeria and the Philippines, of coffee in Kenya and Tanzania and of tea in Taiwan and it occurs in bananas, pawpaws, cassava, citrus, sweet potatoes and millet in countries of Africa, Asia and Central America.
D. aegyptium has also been recorded in the weed flora of the following crops: aubergines in India;black gram (Vigna mungo) in Bangladesh and India;cassava in the Philippines;chickpeas in India;chillies (Capsicum) in India;cotton in Brazil, South China, India, Nepal, Thailand, USA and Zambia;cowpeas in India;finger millet (Eleusine coracana) in India;groundnuts in Bangladesh, Ghana, India, Senegal and USA;maize in India, Nigeria, Pakistan, Philippines and USA;jute in India;mint in India;mung beans (Vigna radiata) in India;okras in Nigeria;pawpaws in the Philippines;pearl millet (Pennisetum glaucum) in Burkina Faso, Mali and India;pigeon peas in India;potatoes in the Philippines;rice (transplanted) in India, Indonesia and Pakistan;rice (upland) in Cameroon, Gambia, India and Nigeria;sesame in India;sorghum in Australia, India;soyabeans in Ghana, India, Côte d'Ivoire, Pakistan, Senegal;sugarcane in India, Taiwan and Peru;sweet potatoes in the Philippines, Taiwan and USA;tobacco in India;wheat in Bangladesh and India;yams in India and the Philippines.
Floating perennial aquatic plant, typically rooted in mud. Plant height up to 100 cm tall. Vegetative stems elongate, developing to and growing at water surface. Flowering stems erect, 8–12 cm, glabrous, distal internode 2–10 cm. Leaves submerged, floating or emergent (or a combination of any two). Sessile leaves submersed, no petiole, alternate on elongate stem. Petiolate leaves emersed;stipule 7–13 cm, apex truncate;petiole never inflated, 11–25 cm;blade round, 7–16 × 2.3–16 cm. Inflorescence a spike or panicle, subtended by 2 reduced, dissimilar leaves. Spikes 7–50-flowered sometimes carrying more than 60 flowers (Gopal, 1987). Flower zygomorphic, spathes obovate, 3–6 cm;peduncle 1.9–15 cm, pubescent with orange hairs. Perianth blue or white, limb lobes obovate, 13–25 mm, margins erose, central distal lobe dark blue at base with yellow distal spot (Haynes, 1988);proximal stamens 15–29 mm, distal 6–20 mm;anthers 1.2–2.3 mm;style 3-lobed. Seeds develop from an anatropous ovule. The fruit contains 10–13-winged seeds (Flora of North America, 2009) 1.5-2.6 mm long, 0.3-0.9 mm wide (Sher, 2009). The roots extend into the substrate, which length varies greatly;5 cm in the younger portions of the stems but can reach up to 1 m in the older portions (Padial et al., 2009).
E. azurea is a rooted perennial aquatic plant with submersed and emersed leaves. Several taxa of this family have spread, as weeds or ornamentals (Barrett, 1978), outside the limits of their native range (Eckenwalder and Barrett, 1986). Eichhornia crassipes is the species best known for its invasiveness;it is one of the most troublesome weeds in the world (Gopal, 1987) and is declared a noxious weed in many countries, including in the USA and in two states in Australia. The status of E. crassipes (water hyacinth) as a weed has led to the subsequent designation of E. azurea and several species of Eichhornia as prohibited imports in various countries (USDA-NRCS, 2016;The State of New South Wales, 2009).
E. azurea was introduced into the USA from South America as an aquatic ornamental in the 1980s. It has occasionally escaped into local environments in the USA (Gopal, 1987) but has not become established as a weed there. According to historical records, E. azurea has been reported in southern Florida and more recently in Texas (TexasInvasives.org, 2016). It has also been reported in Japan but possibly as a temporary occurrence only (Kadono, 2004).
E. azurea is a weed with a widespread distribution in Brazil, where it often creates large floating mats which obstruct navigation and many other uses of aquatic resources. Reproduction is by seed and vegetatively. Dispersal is by whole plants, by water or by birds.
B. sylvaticum is a cespitose perennial bunchgrass that is sometimes very weakly rhizomatous. It ranges in height from a few centimeters up to about 200 cm. Sheaths are open and the nodes are typically pubescent. The leaf blades are bright green and remain green throughout the summer, even in dry Mediterranean climates (BA Roy, University of Oregon, USA, personal observation, 2009). The blades are 4-15 mm wide, flat and lax, with variable pubescence. Ligules are variable in size (1-6 mm) and are generally pubescent and ciliate. Plant size and pubescence depend both on habitat (Shouliang and Phillips, 2006) and genotype (Davies and Long, 1991). Racemes are nodding with an average of 9 spikelets, each with 3-24 florets. Lemma awns are 7-15 mm. Excellent full descriptions are published in the Flora of North America (Piep, 2003) and Flora of China (Shouliang and Phillips, 2006), both of which can also be found on line at www.efloras.org/index.aspx.
For a grass, B. sylvaticum is relatively easy for botanists to identify because it grows in the shade of the forest (and often along trails, streams and rivers) and is quite pretty: it stays a bright vibrant green all season long, and has broad lax leaves and nodding inflorescences. Nonetheless, for identification it is best to involve a trained botanist as there are a couple of native forest grasses in North America with which it could be confused (for example, Bromus vulgaris, and possibly Melica subulata, Elymus glaucus and Bromus carinatus). Excellent identification information can be found at Piep (2003) and Shouliang and Phillips (2006).
B. sylvaticum is a bunchgrass naturally occurring in old world temperate forests and temperate zones of tropical Asian mountains. Its extensive native range includes most of Eurasia (e.g. Europe, Russia, China, Japan, India, Indonesia) as well as the Middle East (e.g. Lebanon, Syria, Iran) and North Africa (e.g. Algeria, Eritrea). It is invasive in North America (Piep, 2003), South America (Zuloaga et al., 1994), New Zealand (Edgar and Connor, 2000), and Australia (IBIS, 2009). It is shade tolerant (Murchie and Horton, 1998), spreads rapidly by seeds (Petersen and Philipp, 2001), has a persistent seed bank (Donelan and Thompson, 1980;Buckley et al., 1997) and is long-lived (Haeggström and Skytén, 1996). It forms monocultures and crowds out native plants and rare butterflies (Kaye and Blakeley-Smith, 2006;Severns and Warren, 2008). Furthermore, grasses significantly reduce recruitment of conifers (Powell et al., 1994;Lehmkuhl, 2002;Kruse et al., 2004). It is on noxious weed lists for three USA States: California, Oregon and Washington (CDFA, 2009;NWCB, 2009;ODA, 2009).
The Pacific Northwest is world renowned for its timber production from conifers. It has not been established through a controlled study that B. sylvaticum in particular competes with conifers;however, several lines of evidence suggest that this grass will reduce survival and growth of conifer seedlings. First, a number of studies have established that the germination, growth and survival of conifers are negatively affected by competition with grasses (e.g. Powell et al., 1994;Lehmkuhl, 2002;Kruse et al., 2004). Second, at least one timber company (Starker Forests Inc.) has noticed that dense patches of false-brome provide safe cover for voles, which girdle conifer seedlings (G Fitzpatrick, The Nature Conservancy, Oregon, USA, personal communication, 2009). Third, none of the native grasses affected form a solid carpet in the forest, whereas B. sylvaticum does. These dense carpets will compete with seedlings in both logged and unlogged forests, and the build up of thatch may increase fire risk (Anzinger and Radosevich, 2008;False Brome Working Group, 2009). On the other hand, because B. sylvaticum remains green throughout the summer it may decrease fire risk (Anzinger and Radosevich, 2008;False Brome Working Group, 2009). These questions about fire need to be addressed with further research because this grass has the potential to cause ecosystem change if it alters fire behaviour.
The native grasses and herbs that live in the habitats being invaded are likely to diminish in cover and may face local extinction as a result of competition. A recent study showed that under shady high nutrient conditions, B. sylvaticum is a superior competitor to a native prairie grass (Festuca roemeri), a native forest grass (Elymus glaucus) as well as to another aggressive invasive Schedonorus arundinaceus (previously known as Festuca arundinacea) (BA Roy, University of Oregon, USA, personal observation, 2009). Two other grasses that occur sporadically in the forest (Melica subulata and Bromus carinatus) are also quite likely to be negatively affected. In its native range, B. sylvaticum is known for its ability to out compete other species due to its rapid relative growth rate (RGR) and ability to form persistent leaf litter (Grime et al., 1988;Haeggström and Skytén, 1996;Alonso et al., 2001).
The following description is taken from Flora of Pakistan (2015).
A. ochroleuca is an annual herb native to Central America. It has been introduced into Australia, Africa, tropical Asia, New Zealand and a number of oceanic islands where it has become invasive. It is most common in disturbed areas such as roadsides, mining dumps, rabbit warrens, recently cultivated paddocks, degraded land and over-grazed pastures. This species produces a large number of seed which can be accidentally introduced into new areas as a seed contaminant. It is often a problem in agricultural land but also has the potential to outcompete native species and decrease biodiversity. A. ochroleuca is toxic to humans and livestock and has thorny spines which can cause injury.
The morphology of S. occidentalis as described by Parsons and Cuthbertson (1992) for Australia and Henderson (2001) for South Africa, closely matches that given for the plant in other parts of the world. It is a low growing, sparsely branching annual or short-lived perennial plant up to 0.5-2 m high and having a characteristic foetid odour. The stems are reddish purple, erect, 4-angled when young, becoming rounded with age. The plant has a robust primary root with several laterals. The leaves are pale green on reddish stalks;alternate, pinnate, with 3-5 (sometimes 6) pairs of opposite ovate to lanceolate-elliptic leaflets, 25-100 mm long, 20-30 mm wide, rounded at the base. A conspicuous, dark-coloured gland occurs at the base of the petiole (leaf stalk) but not on the stalks of the leaflets. The flowers are pale to bright yellow, 20-30 mm in diameter, in 2-6 flowered axils of the upper leaves;sepals are red veined;5 petals per flower, the 2 anterior ones are smaller than the others;fertile stamens 6, the two basal ones longer than the rest, 4 infertile stamens are reduced to tiny petal-like staminodes. Further descriptions of the floral anatomy of S. occidentalis and nine other species of Cassia are given by Chhavi-Thakur and Thakur (1988). The fruit is a dark brown, flattened, sickle-shaped pod with paler stripes along the edges when mature. Pods are 75-130 mm long, 8-10 mm wide, containing a single row of 25-35 seeds. The seeds are dark brown, flattened, hard, 5 mm long and 3 mm wide.
S. occidentalis is an annual to short lived perennial herb to small shrub with a pantropical distribution (PROTA, 2016). It is reported as invasive throughout Oceania, and various countries in Asia and Africa, where is reported as introduced (BioNET-EAFRINET, 2016;PIER, 2016). Within its native range S. occidentalis is listed as invasive for Cuba by Oviedo Prieto et al. (2012).
This species is recognised as an invasive herb or a problematic weed that affects crops and plantations all over its range (PIER, 2016). For example, in the Northern Territory, Australia, it is a class B declared weed, i.e. spread to be controlled in all of the Territory (Flanagan, 1998). This weed is a problem in seven states of the USA and is increasing in eight others (Teem et al., 1980). Its ability to colonize a wide range of climatic and edaphic conditions is epitomized by its occurrence in East Africa where it is found at altitudes of 0-1740 metres above sea level (Brenan, 1967). Though probably less important than the related weeds, S. obtusifolia and S. tora, S. occidentalis has the potential to become a weed of more widespread significance. In the USA it is on the regulated invasive list for Florida (Invasive Plant Atlas of the United States, 2016).
S. occidentalis is commonly cited as a weed of soyabean, groundnut, cotton and pastures (Teem et al., 1980). However, its distribution indicates that it is likely to occur as part of the mixed weed flora of many annual crops in the tropics and subtropics (PROSEA, 2016;PROTA, 2016)..
Erect or ascending, annual or short- perennial herbs or shrublets, 0.5-2 m tall. Stems erect, many branched, glabrous, viscid. Stipules lanceolate, 10-12 × 1-3 mm, membranous, base auriculate, apex acute. Leaves pinnate, 3-8 cm long, grey green to dark green in colour, often with purplish tinge;leaflets (pinnae) 8-38 pairs, 3-15 mm long, 1-3 mm wide, linear or oblong linear;exhibiting nyctinastic (night) and thigmotactic (touch-responsive) movement causing pinnae to fold on the rachis;rachis and leaflet margins and midribs often ciliate. Inflorescences axillary, racemose, laxly branched, 2-4-flowered;bracts cordate, membranous. Bracteoles linear-ovate, striate. Calyx deeply 2-lobed. Corolla from pinkish to yellow, ca. 7 mm. Legume oblong, 2.5-3 cm × 2.5-3 mm, herbaceous to leathery, slightly curved, abaxial suture undulate and indented;articles 4-7, rounded, slightly muricate. Seeds brown, reniform, 2-3 mm long and 1.5-2 mm wide (Cook et al., 2005;Flora of China Editorial Committee, 2015).
Aeschynomene americana is native to tropical and subtropical regions of the Americas and parts of the Caribbean. It has been intentionally introduced in agroforestry systems in tropical and subtropical regions around the world, being used for forage, green manure, and land reclamation in wetlands. Plants are heavy seeding and, once seedlings are established, growth is vigorous and difficult to control. It is also tolerant to waterlogged conditions and can grow on poor soils. Consequently, it has naturalized throughout large parts of the tropics and subtropics and has also become a weed in pastures, agricultural lands, along roadsides, and in any disturbed sites near cultivation. It is listed as invasive in Singapore, Micronesia, Papua New Guinea, Palau, Taiwan, India and Cuba.
Throughout its distribution range, A. americana is listed as a weed of rice, bean, soybeans, and maize plantations (Thro et al., 1990;Bishop, 1992a;Vibrans, 2009;FAO, 2015).
Decumbent or ascending glabrate aquatic perennials, the simple or branched, often fistulose stems to 100 cm. long. Leaves glabrous or glabrate, lanceolate to narrowly obovate, apically rounded to acute, basally cuneate, rarely denticulate, 2-10 cm. long, 0.5-2 cm. broad;petioles 1-3 mm. long. Inflorescences of terminal and occasionally axillary white glomes, 10-18 mm. long, 10-18 mm. broad, the usually unbranched peduncles 1-5 cm. long. Flowers perfect, bracts and bracteoles subequal, ovate, acuminate, 1-2 mm. long;sepals 5, subequal, oblong, apically acute and occasionally denticulate, neither indurate nor ribbed, 5-6 mm. long, 1.5-2.5 mm. broad;stamens 5, united below into a tube, the pseudostaminodia lacerate and exceeding the anthers;ovary reniform, the style about twice as long as the globose capitate stigma. Fruit an indehiscent reniform utricle 1 mm. long, 1-1.5 mm. broad (Flora of Panama, 2016).
A. philoxeroides is one of the worst weeds in the world because it invades both terrestrial and aquatic habitats. The aquatic form of the plant has the potential to become a serious threat to rivers, waterways, wetlands and irrigation systems. The terrestrial form grows forming dense mats with a massive underground rhizomatous root system (ISSG, 2016). This weed is extremely difficult to control, is able to reproduce from plant fragments and grows in a wide range of climates and habitats, including terrestrial areas. In aquatic habitats it has deleterious effects on other plants and animals, water quality, aesthetics, vector populations, water flow, flooding and sedimentation. In terrestrial situations, it degrades riverbanks, pastures, and agricultural lands producing massive underground lignified root systems penetrating up to 50-60 cm deep. Currently, A. philoxeroides is listed as invasive in the United States, Puerto Rico, France, Italy, India, Sri Lanka, China, Taiwan, Indonesia, Myanmar, Singapore, Australia and New Zealand (Weber et al., 2008;Chandra, 2012;Rojas-Sandoval and Acevedo-Rodriguez, 2015;DAISIE, 2016;USDA-ARS, 2016;USDA-NRCS, 2016;Weeds of Australia, 2016). Once established, it behaves as an aggressive invader with the capability to totally disrupt natural aquatic ecosystems, shoreline vegetation and terrestrial and semi-aquatic environments (ISSG, 2016;USDA-NRCS, 2016).
A. philoxeroides primarily affects floating aquatic plants and pastures but submerged and emerged aquatic plants are also affected.
Based on descriptions by Wagner et al. (1999), Struwig and Siebert (2013) and the Flora of North America Editorial Committee (2016), B. coccinea is a prostrate to ascending perennial herb, approximately 90 cm in height, leafy in lower half, diffusely paniculate in upper half. Stems are covered with very short fine straight erect hairs, branching opposite near base, upward usually becoming alternative by suppression of one branch of a pair, angle of branching is wide.
Boerhavia coccinea is a low-lying, sprawling, perennial herb. The plant produces stems that can exceed a metre in length. The flowers are often bright scarlet to red-violet in colour but can be shades of pink, yellow or white. It grows in a wide variety of habitats, such as disturbed, rocky and sandy ground, cultivation edges, waste places, roadsides, seashore and dry riverbeds. It is a widespread pantropical plant whose native range is uncertain, but probably encompasses the southern USA, Mexico, the Caribbean and Central and South America. It has been introduced into Asia, Africa, Australia and some of the Pacific islands, including the Hawaiian Islands. In Hawaii, B. coccinea is an invasive species threatening native plant species and a noxious weed, rapidly spreading and now common in coastal or slightly inland disturbed places such as roadsides.
B. coccinea occurs as a serious weed in upland crops (including upland rice, Oryza sativa) in Gambia (Terry, 1981).
Adapted from Flora Zambesiaca (2014)
C. asiatica is a low-growing perennial with a pan-tropical distribution. It can spread to form a dense ground cover, desirable in some situations but unwelcome in others. It is recorded as invasive in a number of Pacific islands to which it has been introduced and is classed as High Risk (score 7) by PIER (2014), but the situations in which it is causing problems are not clear. It is not especially competitive in crops but may affect wild vegetation and biodiversity. C. asiatica is also among a number of species invasive in the Dongting Lake wetlands, Hunan province, China (Hou et al., 2011).
C. asiatica is recorded as a weed in rice paddies, various plantation crops and forestry, but there are no indications of serious crop loss due to C. asiatica. Where it is listed as invasive, some native species are being impacted but little detail has been seen. In Hawaii, C. asiatica is among introduced species which have contributed to the decline of native sedges Carex thunbergii and Carex echinata (University of Hawaii, 1991).
The following description is taken from Flora of China Editorial Committee (2015):
C. viscosa is an annual herb, up to 160 cm tall. Stems simple or branched, ± glandular hirsute, viscous. Petiole 1.5–4.5(–8) cm, glandular hirsute;leaflets 3 or 5;leaflet blades ovate to oblanceolate-elliptic, (0.6–)2–6 × 0.5–3.5 cm, both surfaces glandular hirsute, margin entire to glandular ciliate, apex acute to obtuse. Inflorescences 5–10 cm but 10–15 cm in fruit;bracts 1–2.5 cm, palmately compound, 3-foliolate, often deciduous, glandular hirsute. Pedicel 0.6–3 cm, glandular hirsute. Inflorescences 3–6-flowered. Sepals green, equal, distinct, 5–10 × 0.8–1.2 mm, lanceolate, persistent, glandular hirsute, base cuneate, margin entire. Petals bright yellow, basally sometimes purple, arranged in an adaxial semicircle before anthesis but radially arranged at anthesis, 7–14 × 3–4 mm, oblong to ovate, clawed. Stamens (dimorphic, 4–10 adaxial ones much shorter with a swelling below anthers) green, 5–9 mm;anthers green, 1.4–3 mm. Pistil 6–10 mm, densely glandular;style 1–1.2 mm;stigma capitate. Fruit capsule 3–10 cm × 2–4 mm, strongly ridged longitudinally, dehiscing only partway from apex to base, glandular pubescent or essentially glabrous. Seeds 25–40 (up to 100) per capsule, light brown, 1.2–1.8 × 1–1.2 mm, compressed spherical, transversely finely ridged.
C. viscosa is a fast-growing herb of humid and warm habitats. It is commonly found growing as a weed in disturbed sites, gardens, rice paddies, pastures, orchards, abandoned lands, and along roadsides (Flora of China Editorial Committee, 2015;PROTA, 2015). This species is included in the Global Compendium of Weeds where it is listed as an environmental and agricultural weed with moderate economic impacts principally in rice paddies and sugarcane plantations (Randall, 2012). It produces large numbers of sticky seeds which can be dispersed by wind, water, and as a contaminant in farm machinery, farm produce, soil, or adhered to clothes and animal fur (Smith, 1981;PROTA, 2015). Currently, C. viscosa is listed as invasive in India, Singapore, Dominican Republic, Puerto Rico, the Virgin Islands, Galapagos Islands, and on several islands in the Pacific Ocean such Fiji, French Polynesia, Guam, and Papua New Guinea among others (Waterhouse, 1993;Kairo et al., 2003;Chandra, 2012;PIER, 2015;Rojas-Sandoval and Acevedo-Rodriguez, 2015).
C. viscosa is a weed in ruderal areas, woodland, grassland, rice paddies, and sugarcane plantations (Holm et al., 1979;Flora of China Editorial Committee, 2015;PROTA, 2015).
C. hirtus is an approx. 50 cm high, annual/ perennial herbaceous, erect or spreading plant. The following description is taken from the Flora of North America Editorial Committee (2016):
Stems erect, 5–10(–25) dm, puberulent in lines, hairs retrorse, blunt-tipped. Leaves: petiole 2–20 mm;blade narrowly lanceolate to elliptic-lanceolate, 2–7 cm, base rounded to obtuse, margins crenate-serrate, proximal teeth not prolonged, apex acute, surfaces glabrous or sparsely hirsute-strigose on veins. Inflorescences usually solitary flowers, sometimes fasciculate or cymose, 2–3-flowered. Pedicels 3–4 mm. Flowers: sepals narrowly oblong-lanceolate, 3–5(–7) mm, not awned, hirsute;petals 4–6 mm;stamens 15–25. Capsules cylindric, terete, not wing-angled, 2-valved, distally abruptly constricted to beaklike apex, without awns, (20–)25–45(–60) × 2 mm, sparsely to moderately strigose to strigulose.
C. hirtus is a herb or subshrub found to be infesting wetlands in Minas Gerias, Brazil due to its high frequency and density (Mascarenhas et al., 1995). In Brazil, it is widely distributed and grows either as a ruderal or as an invading weed infesting pastures. It was listed as a weed in a checklist of invasive plants in forestry plantations in the Lower Amazon (Pires, 1992), but the paper states that the term ‘invasive’ is equated with ‘weed’ defined as any plant growing where it is not wanted, so its status as a true invasive is dubious. It is listed as a weed in several countries by Sinha et al. (2011). It often grows as a weed in grain fields in Central America (Standley and Steyermark, 1949).
C. hirtus is one of the weed species present in rice crops in Colombia (Ramírez et al., 2015). It is also found growing with other agricultural crops such as cotton, cassava, maize and beans (Blawid et al., 2013).
E. paniculata usually grows as an annual or short-lived perennial plant. It is rooted in mud in shallow waterways. Submersed sessile leaves form a basal rosette and are linear to oblanceolate. Petiolate leaves are above the water surface with a cordate blade, acuminate to acute at the tip. Petiolate leaf blades grow 7.5-15 cm long, 3.5 – 9 cm wide, and the petiole may be up to 60 cm long. The flowers grow on separate flowering stalks in a panicle with 5-100 flowers developing over several days. The peduncle is sparsely glandular-pubescent to glabrous, 11.5-17.5 cm long;spathe linear, 13-35 mm long, the apex acuminate. Flowers are blue, white or lilac. The floral tube is 8-10 mm long, tepals are 12-15 mm long. The central upper tepal has two yellow spots toward the base. Upper and lower stamens are 2.5-3.5 mm and 5.1-8.5 mm long respectively. Stigmas are 3-lobed and tristylous. Seeds form in capsules 6-8mm long. Seeds are 0.6-1.0 mm long, 0.6-0.8 mm wide with 10-12 longitudinal wings (Barrett and Husband, 1997;Flora of the Guianas, 2016).
Eichhornia paniculata can grow in monocultural stands in shallow wetlands (Barrett and Husband, 1997). It is listed as a transformative species in Cuba by Oviedo-Prieto et al. (2012), although other sources suggest that it is native to Cuba (FreshFromFlorida, 2016). Listed as a prohibited aquatic plant in Florida along with all species of Eichhornia (USDA-NRCS, 2016), because of the invasive nature of other species in the genus. It appears to have naturalized only in Guyana (Funk et al., 1997) and is listed as an agricultural weed of rice fields in Jamaica and Cuba (Barrett, 2011).
A weed of rice fields in Jamaica and Cuba (Barrett, 2011).
E. fosbergii is an annual, erect or ascending herb, branched, 20 to 50 cm (up to 100 cm) tall. Stems glabrous to sparsely pilose or sometimes prominently villous-pilose near the axils of the middle cauline leaves. Leaves alternate, broadly ovate to oblanceolate, often tapering to a prominently winged petiole and therefore appearing pandurate, the base sessile to auriculate, the margin weakly serrate to dentate or sometimes lobed, the teeth callose-tipped, overall 5-10 cm long, 2-5 cm wide, about 2 times longer than wide, the uppermost leaves reduced to linear serrate clasping bracts. Inflorescence of one to several headed, loose, corymbiform cymes arising terminally or laterally in the axils of the upper cauline leaves. Heads turbinate or sometimes weakly urceolate or becoming weakly campanulate in age, robust, 2-3 times longer than wide, the florets prominently exserted approximately 2 mm beyond the involucre;involucral bracts 8-13, linear, (7-) 9-12 mm long;receptacle flat to convex, the carpopodia forming prominent tubercles after achenes have been shed;florets 15-30, varying greatly in size with the robustness of the plant, the corollas pink to light purple or red but not orange. Achene reddish brown to light tan, columnar, approximately 5 mm long with a row of strigose-hirsute pubescence on each of the 5 prominent ribs;pappus of abundant, white, capillary hairs (Flora of Taiwan Editorial Committee, 2014;Missouri Botanical Garden, 2014).
E. fosbergii is a cosmopolitan annual herb included in the Global Compendium of Weeds (Randall, 2012). It is fast-growing, with the capacity to grow as a weed and colonize disturbed areas, waste ground, gardens, abandoned farmland, coastal forests, forest edges, pastures, roadsides, rocky areas, and riverbanks (Wagner et al., 1999;Vibrans, 2011;Pruski 2014). It produces large amounts of wind-dispersed seeds (5000 seeds per plant;Mejía et al., 1994) which is a feature facilitating the likelihood of spreading and colonizing new habitats. Currently, E. fosbergii is listed as invasive in Mexico, Central America, West Indies, and on several islands in the Pacific Ocean (see Distribution Table for details).
E. fosbergii has been listed as a weed in rice plantations in Colombia and coffee plantations in Costa Rica. It is also listed as a weed in cassava and sugarcane plantations in Central and South America (Echegoyen-Ramos et al., 1996, Murillo et al., 2006;Vibrans, 2011).
The following description is from Flora of China Editorial Committee (2017)
I. carnea subsp. fistulosa is considered a serious weed in cultivated rice fields due to its strong competitive ability (Frey, 1995).
Perennial, loosely tufted to rhizomatous. Culms erect or geniculate and rooting from lower nodes, up to 100 cm or more tall. Leaf sheaths glabrous;leaf blades tough, usually involute, 5-30(-50) × 0.15-0.3(-0.6) cm, adaxial surface scabrid, abaxial surface subglabrous;ligule 3-12 mm, acute. Inflorescence 15-25 cm, scabrid;racemes 3-28, indistinctly unilateral, 4-20 cm, straight, ascending or spreading, spikelets usually distant. Spikelets glaucous-green, subterete, 6-14 mm, florets 5-12;glumes keeled;lower glume lanceolate, 2-3 mm, acute;upper glume narrowly oblong, 3-4 mm, acute or mucronate;lemmas narrowly oblong, dorsally sub-rounded, lowest 4-5 mm, lower lateral veins pilose, entire or 2-dentate, midvein often produced into a short 0.3-1.6 mm awn;palea ciliolate along upper keels. Callus laterally pilose. Anthers 0.5-0.75(-2.5) mm. Caryopsis elliptic-oblong, 1.5-2.5 mm, dorso-ventrally flattened. Flowers from June to September (based on description of L. fusca ssp. fusca from Flora of China, 2014).
L. fusca is a perennial weed with a global distribution. It is an aggressive species showing a competitive advantage in many situations due to its tolerance of saline and alkaline soils and its likely ability to fix nitrogen. It is commonly a serious weed of rice in many countries, and is of particular concern in Spanish rice fields. It is recorded as invasive on Hawaii and in the Chagos Archipeligo (as L. fusca ssp. uninervia) (PIER, 2014) and has been the subject of an ‘eradication action’ in Europe (Brunel et al., 2013).
L. fusca (mainly ssp. fasciculari) is a major weed of rice in a number of countries including USA, Cuba and Spain. L. fusca ssp. fusca is also problematic in rice in India and other countries. It can also occur in lucerne/alfalfa, tomatoes and turf.
L. peploides is an emergent and floating herbaceous perennial macrophyte. It has glabrous or pubescent stems 1-30 dm that can creep horizontally as well as grow vertically. Early growth resembles a rosette of rounded leaves growing on the water’s surface. Alternate leaves are polymorphic and less than 10 cm long and oblong to round, often lanceolate at flowering. The species exhibits root dimorphism and has adventitious roots that form at nodes and ensure oxygen uptake. Flowers are 5-merous (pentamerous), grow from leaf axils, are bright yellow, and can be from 7 to 24 mm long. Fruit is in a five-angled reflexed capsule, about 3 cm long that contains 40-50 seeds 1.0-1.5 mm long, embedded in the inner fruit wall (EPPO, 2004;The Jepson Online Interchange, 2009).
L. peploides is a productive emergent aquatic perennial native to South and Central America, parts of the USA, and likely Australia (USDA-ARS, 1997). It was introduced in France in 1830 and has become one of the most damaging invasive plants in that country (Dandelot et al., 2008). It is often sold as an ornamental, which likely explains its introduction to Europe. It has been more recently introduced to areas beyond its native range in the USA, where it is often considered a noxious weed (INVADERS, 2009;Peconic Estuary Program, 2009). L. peploides is adaptable, and tolerates a wide variety of habitats where it can transform ecosystems both physically and chemically. It sometimes grows in nearly impenetrable mats;it can displace native flora and interfere with flood control and drainage systems, clog waterways and impact navigation and recreation (Peconic Estuary Program, 2009). The plant also has allelopathic activity that can lead to dissolved oxygen crashes, the accumulation of sulphide and phosphate, ‘dystrophic crises’ and intoxicated ecosystems (Dandelot et al., 2005).
Impacts on the local environment by L. peploides can be devastating. The species possesses an allelopathic activity that has year-long effects on water quality and can lead to impoverished flora by decreasing seedling survival of vulnerable native taxa (Dandelot et al., 2008). L. peploides can also cause severe hypoxia and sometimes anoxia during the summer. It can also lead to reduced sulphate and nitrate levels and increased sulphide and phosphate concentrations. These combined effects have the capability of fomenting what Dandelot et al. (2005) refer to as “a dystrophic crisis” and an intoxicated ecosystem. The plant has been reported to outcompete native Myriophyllum and Potamogeton species in France, which translates to a reduction in macroinvertebrate habitat (Dutartre, 1986;CEH, 2007). It also supplants native wetland grasses, some of which are used as forage for livestock (CEH, 2007).
Herbs 10-20 cm tall, annual or perennial, creeping, sprawling, prostrate, or decumbent. Stems villous, often rooting at nodes. Petioles 0.2-3 (-4) cm, villous;leaf blade elliptic to ovate, 1-2 × 0.4-1.2 cm but basal ones sometimes 6-12 × 3.5-5 cm, both surfaces villous, base cuneate, margin entire, apex acute. Spikes 1.5-4 cm long;bracts elliptic, overlapping, 6-7.5 × 3-4 mm, 5-7 veined. Calyx abaxial lobe approximately 2 × 0.6 mm, apex 2-lobed;adaxial lobe approximately 3 × 1 mm;lateral lobes approximately 2 × 0.5 mm. Corolla bluish purple or white, externally glabrous;tube cylindric for approximately 1.5 mm, contracted near midpoint then expanded into throat;lower lip approximately 2.3 mm;upper lip approximately 2 mm. Stamens inserted at base of throat;filaments 0.5 mm, glabrous. Ovary glabrous with 4-8 ovules per locule. Fruit a capsule of approximately 5 × 2 mm, 8 to 16 seeds. Seeds broadly ellipsoid and granulate (Flora of China Editorial Committee, 2014).
N. canescens has been recorded growing as a weed in rice, maize, melon, and oil palm plantations (Ekeleme and Chikoye, 2003;Essandoh et al., 2011;Mahbubur, 2013).
The following description is taken from Flora of North America Editorial Committee (2016)
N. lotus is a floating leafed macrophte and water lily, native to Africa and specific areas in Europe. It has a number of medicinal properties and is often introduced into new areas as an ornamental. This species has become naturalized in North America and some countries in South America and Asia, but no published reports of it being invasive were found other than presence (without further details) on an invasive species list for Louisiana (Louisiana Department of Wildlife and Fisheries, 2015). There are limited reports of the impact of this species, although in newly reclaimed wetlands in the Nile Delta, Egypt, N. lotus has been observed colonizing rice fields causing a significant decrease in growth and yield. Khedr and Hegazy (1998) describe it here as having "rampant behaviour as an aquatic weed invading the newly reclaimed ricefields," with its aggressiveness related to being able to spread through both vegetative and sexual reproduction.
N. lotus is recorded as a weed in rice fields in Egypt where it can significantly reduce the growth and grain yield of the crop (Khedr and Hegazy, 1998;Hegazy et al., 2001).
The following description is from Flora of China Editorial Committee (2017)
Paspalum dilatatum is a perennial grass native to South America that has been introduced into tropical and subtropical areas as a forage species/fodder. It is reported as invasive in Japan, Malaysia, Taiwan, Vietnam, Indonesia, Philippines, Hawaii, American Samoa, Australia, Fiji, French Polynesia, New Caledonia, New Zealand, Niue, Norfolk Island, Solomon Islands and the Minor Outlying Islands. In Hawaii and New Zealand, it forms dense stands that smother and prevent recruitment of native species.
P. dilatatum is reported as a weed of cultivation and is sometimes present in rice fields (Heuzé et al., 2015;Flora of China Editorial Committee, 2017). When the species is infected by the ergot fungus, Claviceps paspali, it becomes toxic to animals that feed on it (FAO, 2017;PROTA, 2017;USDA-ARS, 2017).
Perennial with short rhizomes (a few cm only) and long above-ground runners (up to 2 m long), rooting at each node. Culms solitary or tufted, many-noded, 10-50 cm tall. Leaf sheaths imbricate, often keeled, margins membranous;leaf blades distichous, linear, rather stiffly ascending, 2.5-15 × 0.3-0.8 cm, apex acute;ligule 0.5-1 mm. Inflorescence of (1-)2(-3) racemes arising together at culm apex;racemes 2-5 cm, usually closely approximate when young, later spreading;spikelets single, in 2 rows;rachis 1-2 mm wide. Spikelets pale brownish green, narrowly lanceolate-oblong, strongly flattened, 3.5-4 mm, acute;lower glume absent or rarely a tiny vestige;upper glume thinly papery, weakly 5-veined, midvein often suppressed, glabrous;lower lemma resembling upper glume;upper lemma pale green, 2.5-3 mm, shorter than spikelet, cartilaginous, apex minutely pubescent. Caryopsis narrowly obovate, slightly concavo-convex, 2.5-3 mm long, subacute (Flora of China Editorial Committee, 2016;PIER, 2016).
Paspalum vaginatum, commonly known as seashore paspalum and by many other names, is a species of perennial grass which can be found in wet, saline habitats. Reported to have originated from the Americas, it can be a serious weed of rice in West Africa. In coastal habitats, it can spread at 1-2 m per year and become dominant over native vegetation. In New Zealand, it is of concern having invaded the nesting areas of the endangered New Zealand fairy tern (Sterna nereis), threatening a range of uncommon or endangered plant species, and possibly affecting fish breeding. PIER (2016) assesses it as a 'High Risk' species (score 7) for the Pacific islands and confirms it as invasive in Hawaii (on golf courses) and the Marshall Islands, also on Diego Garcia in the Indian Ocean. In Spain it is classed as a species with ‘clear invasive behaviour;dangerous (causing ecological damage or alteration) for natural ecosystems’ (Dana et al., 2007). Similarly it is regarded as a threat to native vegetation in California, USA (Riefner and Columbus, 2008).
In many regions, P. vaginatum is a serious weed of rice, especially in saline and brackish soils (Bernard, 1988;Terry, 1981).
R. ellipticus is a stout, weakly climbing, evergreen shrub 1–3 m tall. Branchlets purplish brown or brownish, pubescent, with sparse, curved prickles and dense, purplish brown bristles or glandular hairs. Leaves imparipinnate, 3-foliolate;petiole 2–6 cm, petiolule of terminal leaflet 2–3 cm, lateral leaflets subsessile, petiolule and rachis purplish red bristly, pubescent, with minute prickles;stipules linear, 7–11 mm, pubescent, with intermixed glandular hairs;blade of leaflets elliptic or obovate, 4–8(–12) × 3–6(–9) cm, terminal leaflet much larger than lateral leaflets, abaxially densely tomentose, with purplish red bristles along prominent veins, adaxially veins impressed, pubescent along midvein, base rounded, margin unevenly minute sharply serrate, apex acute, abruptly pointed, shallowly cordate, or subtruncate. Inflorescences terminal, dense glomerate racemes, (1.5–)2–4 cm, flowers several to 10 or more, or flowers several in clusters in leaf axils, rarely flowers solitary;rachis and pedicels pubescent, bristly;bracts linear, 5–9 mm, pubescent. Pedicel 4–6 mm. Flowers 1–1.5 cm in diameter. Calyx abaxially pubescent, intermixed yellowish tomentose, sparsely bristly;sepals erect, ovate, 4–5(–6) × 2–3(–4) mm, abaxially densely yellowish gray tomentose, apex acute and abruptly pointed. Petals white or pink, spatulate, longer than sepals, margin premorse, densely pubescent, base clawed. Stamens numerous, shorter than petals;filaments broadened and flattened basally. Ovary pubescent;styles glabrous, slightly longer than stamens. Aggregate fruit golden yellow, subglobose, approximately 1 cm in diameter, glabrous or drupelets pubescent at apex;pyrenes triangular-ovoid, densely rugulose (Wagner et al., 1999;Flora of China Editorial Committee, 2015).
The invasiveness of the thorny shrub R. ellipticus has been most thoroughly documented on the island of Hawaii. Since the first report of its escape from cultivation in 1961, this species has become established in mid-elevation forest and pastureland, forming tall, dense thickets. Seeds are sufficiently viable following passage through the digestive systems of birds and mammals to readily germinate in pastureland and undisturbed forest sites where they are deposited. Several introduced frugivorous birds and feral mammals, are capable of dissemination of seeds via ingestion of the succulent fruit and birds in particular, are able to carry seeds to adjacent sites. It can also spread by suckers and resprouts vigorously after fire. The ability to colonize undisturbed native forests and displace native species is cause for alarm among resource managers of Hawaii Volcanoes National Park and other natural reserves of Hawaii, comprised of highly ecologically sensitive systems. It has been listed as one of the world’s 100 worst invasive alien species (Lower et al., 2000), and is a prohibited species in South Africa (NEMBA Category 1a).
R. ellipticus encroaches upon rice fields in China and elsewhere in Asia if farmers do not manually control this bramble. R. ellipticus invades apple, and other temperate fruit orchards in India (Misra and Sharma, 1970;Misra and Singh, 1972). Its weedy habit is particularly evident in Hawaii where it aggressively colonizes cleared pastureland and encroaches into native forests, forming tall, dense thickets.
S. indica is a tufted mostly glabrous annual that can grow to 0.6 m high.
As the only cosmopolitan species within the genus, S. indica is best described by length of its spikelet, the length if its upper glume, the length of the inferior lemma, the length of its anther upper flower, its hyaline ligules and its having an apex acute upper glume (Gennaro and Scataglini, 2012). Simon (1972) wrote that it is ‘characterized by a spikelet containing two florets of which the lower is male or barren, and the upper hermaphrodite. It is delimited from the type genus Panicum by the strongly saccate nature of the base of the upper glume and to a lesser extent of the lower lemma, and by the inflorescence... being a false spike (morphologically a much contracted panicle)’ (Simon, 1972). S. indica can also be distinguished from the rest of Paniceae by the presence of spiciform panicle with ribbed glumes and gibbous upper glumes (Teerawatananon et al., 2011).
S. indica is very similar to other Sacciolepis species such as S. spiciform (Flora Zambesiaca, 1989). Flora Zambesiaca conserves that S. indica ‘ can usually be distinguished by spikelet length and habit, but absence of leaf papillae is the most reliable character though it requires use of a microscope.’ Spikelet length and smooth pedicels can be used to quickly distinguish S. indica from S. myosuroides (Simon and Alfonso, 2012).
African specimens of S. indica often have little auricles. These specimens have been described as S. auriculata in the past. However, according to Flora Zambesiaca (1989), S. indica intergrades completely from forms with auricles to the commoner form that lacks auricles (Scholz, 1980;Flora Zambesiaca, 1989).
S. indica is an annual C3 grass (Aliscioni et al., 2003;De Gennaro, 2011). It is highly variable in size, spikelet length and pubescence, and it flowers sporadically throughout the year (Simon and Alfonso, 2012). S. indica is found in tropical and subtropical rainforests, tropical and subtropical sub-humid woodlands, and coastal grasslands.
Annual grass. Culms slender, creeping, rooting at lower nodes, ascending to 10-50 cm tall. Leaf sheaths glabrous, one margin densely ciliate;leaf blades lanceolate, 2-6 × 0.3-1.2 cm, glabrous or loosely hispidulous, base subcordate, margins scabrous, pectinate-ciliate at base;ligule c. 1 mm, ciliate. Inflorescence pyramidal, axis 1-8 cm;racemes 3-6(-12), 0.5-4 cm, spreading;rachis triquetrous, scabrous;spikelets paired, crowded, pedicels setose. Spikelets ovate or ovate-elliptic, 2-2.5 mm, usually glabrous, acute;lower glume cufflike, 1/8-1/4 spikelet length, thinly membranous, veinless or obscurely 3-veined, truncate or rounded;upper glume (5-)7-9-veined;lower lemma 5-veined, palea well developed;upper lemma broadly elliptic, 1.8-2 mm, finely rugose, apiculate (Flora of China Editorial Committee, 2018).
Urochloa reptans is an annual grass regarded as native to Asia, the Arabian Peninsula, Australia and the Pacific region, although its status is ambiguous in many countries. The species grows forming clumps of slender, creeping culms up to 50 cm tall that are capable of displacing other plants and grasses. It is considered an important weed in agricultural lands and pastures, but it can also invade disturbed sites, degraded forests, coastal areas, river and creek beds, and riparian forests. Currently, it is listed as invasive in Costa Rica, Puerto Rico, the United States Virgin Islands and some islands in Oceania, where it has been reported invading relatively undisturbed forests.
U. reptans is considered a weed of soybean, cotton, maize, rice, sugarcane fields and active pastures (including heavily-grazed pastures). It also grows as a weed of gardens and lawns (Tiwari and Kurchania, 1990;Auld and Kim, 1996;Gupta, 2013;PIER, 2018).
The following description is from the Flora of China Editorial Committee (2016)
Erechtites hieraciifolius is a fast-growing, annual herb that is native to North, Central and South America and the Caribbean. It is recorded as an environmental and agricultural weed in areas both within and outside its native distribution. Mature plants can produce large amounts of wind-dispersed seed, facilitating the colonisation of new areas. It is adapted to grow in a wide range of disturbed anthropogenic habitats and can outcompete other species to form dense populations. It may also spread as a seed contaminant of crops. Currently, it is listed as invasive in Hong Kong, Hawaii, the Galapagos Islands, French Polynesia, Palau, US Minor Outlying Islands, New Zealand and Hungary. It is also considered a potential weed in Australia, where it is under quarantine.
E. hieraciifolius has been listed as a weed of the following crops: oat (Avena sativa), barley (Hordeum vulgare), maize (Zea mays), strawberry (Fragaria ananassa), onion (Allium cepa), carrot (Daucus carota), cranberry (Vaccinium macrocarpon), blueberry (Vaccinium spp.) and sugarcane (Saccharum officinarum);it is also a weed of fodder crops (e.g. Medicago sativa) and of mixed pastures (Darbyshire et al., 2012).
G. quadriradiata is an annual herb, 8–62 cm tall. Leaf blades 20–60 × 15–45 mm. Peduncles 5–20 mm. Involucres hemispheric to campanulate, 3–6 mm diameter. Phyllaries deciduous, outer paleae deciduous, broadly elliptic to obovate, 2–3 mm;inner deciduous, linear to lanceolate, 2–3 mm, entire or 2- or 3-lobed, lobes to 1/3 total lengths, blunt. Ray florets (4 or) 5 (to 8);corollas usually white, sometimes pink, laminae 0.9–2.5 × 0.9–2 mm. Disk florets 15–35. Ray achenes 1.5–2 mm;pappus of 6–15 fimbriate scales 0.5–1 mm;pappus absent or of usually 14–20, rarely 1–5, white, lanceolate to oblanceolate, fimbriate, sometimes aristate, scales 0.2–1.7 mm (Flora of North America Editorial Committee, 2014).
G. quadriradiata is a fast-growing annual herb with the capacity to invade agricultural and other disturbed areas in most temperate and subtropical regions of the world (Kagima 2000;Vibrans, 2009;Kabuce and Priede, 2010;Madsen and Wersal, 2014). It is highly competitive and can spread quickly, often being the dominant species in a field. It is causing considerable economic impact in cropping systems, greenhouses, gardens and nurseries (Madsen and Wersal, 2014). In Europe, this species is recognized as a significant problem for many growers and farmers, including in commercial greenhouses, and its presence may reduce yields up to 10-50% in fields planted with vegetables and crops (Kabuce and Priede, 2010;Madsen and Wersal, 2014).
G. quadriradiata is considered to be a common weed in several crops of major importance, such as wheat, maize, coffee, cotton, tobacco, sugarbeet, tomato, pepper, potato, beans, onions, cabbages, garlic, citrus, banana, apple, and strawberry. It is also a common weed in gardens, greenhouses, and nurseries (Damalas, 2008;Vibrans, 2009;Kabuce and Priede, 2010;Madsen and Wersal, 2014).
P. paniculatum is a perennial grass;culms densely tufted, 0.3 to more than 2 m high, coarse, leafy, erect or ascending, sometimes decumbent at the base and rooting at the lower nodes, finally branching, the nodes glabrous to conspicuously bearded with stiff ascending hairs;sheaths mostly longer than the internodes, keeled, sometimes only on the collar and along the margins, colored orange-brown on the inner surface;ligule 1-3 mm long;blades 9-50 cm long, 6-25 mm wide, usually rounded at the base, densely hispid on both surfaces to nearly glabrous, with a tuft of long hairs on each side at the base, the margins scabrous;inflorescence 5-30 cm long, composed of 7-60 approximate, solitary or somewhat fascicled racemes, the lower ones 4-12 cm long, ascending or arcuate- spreading;spikelets paired, 1.3-1.5 mm long, densely crowded, the glume and sterile lemma equal, barely covering the fruit, softly pubescent, the sterile lemma woolly pubescent only on the margins;fruit about as large as the spikelet, smooth and shining (Flora of Panama, 2016).
P. paniculatum is a fast-growing grass sometimes used as an “auxiliary forage” crop (PROTA, 2016). Within and outside its native distribution, P. paniculatum behaves as an environmental and agricultural weed and can be found growing along roadsides, in disturbed places, moist shrublands, low open grounds, brushy slopes, forests, open ground, croplands and pastures (Zuloaga et al., 2003;Más and Garcia-Molinari, 2006;Más and Lugo, 2013;AusGrass2, 2016). Plants produce numerous seeds with germination rates higher than 85% (range: 86.5 to 99%, PROTA, 2016). Currently, this species is listed as invasive on Hawaii, Cuba, Trinidad and Tobago, Samoa, Northern Marianas Islands, Micronesia, Fiji, French Polynesia, New Caledonia, Niue, Palau and the Solomon Islands (Wagner et al., 1999;Oviedo Prieto et al., 2012;PIER, 2016;Trinidad and Tobago Biodiversity, 2016).
From Flora of China (2015)
L. vulgaris is a perennial flowering plant with a spreading root system. It forms dense mats which can compete with crops and suppress native vegetation, reducing pasture productivity and/or biodiversity (ISSG, 2015). Native to temperate areas of Europe and Asia, it has been widely introduced to North America, Australia, New Zealand and South Africa, and is regarded as noxious in many of these countries. By inclusion in indexes of invasive species it is regarded as invasive widely in Canada and in the USA (Alberta Invasive Species Council, 2014;Invasive Plant Atlas of the United States, 2015). L. vulgaris received an invasive index of 69 (out of a maximum of 100) in Alaska, USA (ANHP, 2011). It is also regarded as invasive within its native range in Serbia (Dzigurski and Nikolic, 2014).
Although L. vulgaris is most common in non-crop and pasture situations, it is recorded as a significant weed in a wide range of annual and perennial crops, including wheat, barley, oats, rapeseed, mustard, pea, strawberry, raspberry, lucerne, orchard crops and vines (McClay and De Clerck-Floate, 2001;De Clercke-Floate and McClay, 2013;Mason and Gillespie, 2013).
Herbaceous vine, much branched from the base, climbs by means of tendrils and attains 1.5-2 m in length. Stems with 5 longitudinal ribs, glabrous or puberulent;cross section with a single vascular cylinder. Leaves alternate, biternate;leaflets chartaceous, puberulent or sparsely pubescent, the apex obtuse, acute, or acuminate, the base attenuate, the margins lobate or laciniate;terminal leaflet lanceolate or triangular, rhombic or narrowly lanceolate in outline, 2-3.5(5) cm long;lateral leaflets ovate, lanceolate, or oblong in outline, 1-2.5 cm long;rachis and petiole not winged;petioles 2-3 cm long;stipules lanceolate, approximately 5 mm long;tendrils in pairs, spirally twisted, at the end of short axillary axes (aborted inflorescences), from which an inflorescence usually develops. Flowers functionally unisexual, zygomorphic, in axillary racemiform thyrses, shorter than the accompanying leaf. Calyx light green, of 4 unequal sepals, the outer ones approximately 1.2 mm long, the inner ones 3-3.5 mm long. Petals white, obovate, 2.5-3.5 mm long;petaliferous appendages slightly shorter than the petals, fleshy and yellow at the apex, forming a hood that encloses the apex of the glands of the disc;disc unilateral, with 4 rounded or ovoid glands, approximately 0.4 mm long;stamens 8, the filaments unequal, pubescent;ovary trilocular, with one style and 3 stigmas. Capsules brown, pearlike, turbinate-obtriangular or sometimes nearly ellipsoid, 1.5-3 × 2-4 cm, pubescent. Seeds black, shiny, approximately 5 mm in diameter;hilum green when fresh, white when dry, cordate (Acevedo-Rodríguez, 2005;Flora of China Editorial Committee, 2015).
C. halicacabum is a long-lived scrambling, creeping, or climbing vine that is a weed of gardens, roadsides, disturbed sites and plantations. It has also the ability to climb and cover mature trees up to 8 m or more in height (Weeds of Australia, 2015). This species is often cultivated as an ornamental in gardens of tropical and subtropical regions of the world for its inflated balloon shaped fruits (Acevedo-Rodríguez, 2005;PIER, 2015;PROTA, 2015;Weeds of Australia, 2015). It has escaped from cultivation, and once naturalized it grows over native vegetation smothering trees, shrubs and understory vegetation. It is very successful invading forest margins, woodland, grassland, riverbanks, floodplains and rocky sites. Dense infestations can also impede access, increase the risk and intensity of fires and harbour pests and diseases (Invasive Species South Africa, 2015). Currently, C. halicacabum is regarded as a weed and invasive species in Australia, South Africa, Kenya, Tanzania, Uganda, French Polynesia, the Cook Islands, New Caledonia, Singapore, the USA, and Cuba (Foxcroft et al., 2003;Oviedo Prieto et al., 2012;BioNet-EAfrinet, 2015;PIER, 2015;USDA-NRCS, 2015;Weeds of Australia, 2015).
C. halicacabum is a weed with substantial economic impacts on sugarcane and soyabean plantations (Gildenhuys et al., 2013).
E. japonica is an annual or short-lived perennial grass. Culms erect, or geniculate at base, 30–100 cm tall, 1.5–2.5 mm in diameter, 3–4-noded. Leaf sheaths usually loose, longer than internodes, glabrous;ligules scarious, approximately 0.5 mm, fimbriate at apex, pubescent on back;leaf blades flat, 3–25 × 0.3–0.5 cm, smooth and glabrous. Panicle elongated, 6–34 × 1.5–6 cm;branches slender, clustered or verticillate, glabrous in axils. Spikelets usually purplish at maturity, ovate, 1–2 mm, 4–8-flowered;rachilla distarticulating between florets from top downward at maturity. Glumes chartaceous, ovate-lanceolate, subequal, 0.6–0.8 mm, 1-veined, apex obtuse. Lemmas chartaceous, broadly elliptical, distinctly 3-veined, apex obtuse, lower lemma approximately 1 mm. Palea subequal to lemma, along 2 keels ciliolate. Stamens 2;anthers approximately 0.2 mm. Caryopsis red-brown, ovoid, 0.4–0.5 mm (Flora of China Editorial Committee, 2016;Flora of Pakistan, 2016).
E. japonica is a good fodder grass cultivated for pasture in tropical and subtropical regions (Kumar, 2013;USDA-ARS, 2016). It has escaped from cultivation and naturalized principally in disturbed sites. This species behaves as a weed in abandoned pastures, cultivated land, disturbed sites, waste areas, and along roadsides and riparian areas (Barkworth et al., 2004;Flora of China Editorial Committee, 2016;PIER, 2016;PROTA, 2016). Currently, it is listed as invasive in Argentina, Brazil, and Cuba (Zuloaga et al., 2008;Oviedo Prieto et al., 2012;I3N-Brasil, 2016). It is well adapted to grow in seasonally waterlogged conditions and can be found growing in floodplain grassland and swampy grassland (Flora of Pakistan, 2016).
From PROTA (2013)
E. hypericifolia is a herbaceous shrub native to the Americas. It is regarded as an invasive weed in many of the Pacific Islands in which it occurs, especially Hawaii, where it is rated ‘high risk’. It is also a weed in Singapore and Taiwan, though the situations in which it is causing problems are not well documented. It is recognized as a weed in soyabean, sugar cane and cotton in some countries and is presumably also threatening native flora in others.
E. hypericifolia is recorded as a weed in soyabean, sugarcane and cotton.
Following PIER, 2015 and Flora of China Editorial Committee, 2015
C. maculatum is an herbaceous biennial and highly toxic plant, native across northern Europe, western Asia and North Africa. It has been introduced widely outside its native area to many parts of America, southern Africa, China, New Zealand and Australia. C. maculatum is a twofold invader, competing with pasture and crops and encroaching on native vegetation, while also posing a serious health hazard to virtually all livestock, and humans. Even within its native range, C. maculatum is increasing and tending to occur more commonly in crops.
Although growing mainly in non-crop areas, C. maculatum can invade field edges and encroach significantly on crops: maize in New Zealand;sugar beet in Slovakia and in France;pastures in Turkey, Poland, Australia and New Zealand;olive in Spain;lucerne (alfalfa) in USA;sunflower in Czech Republic;chickpea in Spain. Mitich (1998) refers to its occurrence in pastures, cereals, vegetable crops and orchards in many countries.
The following description is taken from the Flora of China Editorial Committee (2016):
Annual, tufted. Culms 15–100 cm tall. Uppermost leaf sheath inflated;leaf blades 2–9 mm wide;ligule 2–8 mm. Panicle dense, narrowly oblong, 4–10 cm, base enclosed in uppermost leaf sheath. Spikelets arranged in clusters composed of 1 fertile spikelet encircled by 6 sterile spikelets, clusters falling entire, sterile spikelets sometimes reduced to club-shaped clusters of glumes. Fertile spikelet: glumes 4.5–6 mm, prominently 7–9-veined, narrowly winged, wing expanded near middle into large tooth, pale green or straw-coloured with dark green stripe above tooth, apex attenuate;sterile lemmas abortive, represented by 2 minute fleshy scales at base of fertile lemma;fertile lemma elliptic, 2.8–3.2 mm, cartilaginous, shiny, sparsely pilose toward apex. Anthers 1–1.8 mm.
P. paradoxa is a tufted annual grass which is considered a weed in many areas and can be invasive. It contains tryptamine alkaloids, which are toxic to some animals. It is native to the Mediterranean region of Europe, but has spread to locations including the USA, Australia and South America. It is a serious weed of wheat in Australia, with its success attribued to high seed production, innate dormancy and periodicity of emergence (Taylor et al., 1999).
A list of crops in which the annual Phalaris spp. (P. paradoxa, P. brachystachys and P. minor) are actual, or potential weed problems would include virtually every annual winter (autumn-sown) crop of temperate regions and every annual summer (spring-sown) crop in colder, subtemperate regions within the geographical range of these species. The list provided includes only those crops where Phalaris species are commonly reported as weed problems. P. paradoxa is most often listed as a weed of cereals (especially wheat), and is the second most prominent annual winter grass weed in the northern grain region of Australia (Taylor et al., 1999).
This description was taken from the Flora of China Editorial Committee (2018)
Sonchus asper is an annual herb considered native to Europe, Africa and Asia that has been introduced to a wide range of countries around the world, where it frequently becomes an environmental and agricultural weed. The species grows in a wide range of habitats and climates, and produces large numbers of seeds (20,000 seeds), which are easily dispersed by wind and water, but also as contaminants. Because S. asper is very successful colonising disturbed sites, as well as natural habitats at early successional stages, it has the potential to outcompete native plant species, inhibit the establishment of other native pioneer species and thus alter natural successional processes. It is also regarded as a noxious species due to hosting diseases and pests that affect crops.
S. asper has been listed as a weed of alfalfa, cotton, coffee, beans, garbanzo beans, tomato and maize plantations (Villaseñor and Espinosa, 1998;Vibrans, 2009).
D. caricosum is a perennial, stoloniferous grass. Culms tufted at nodes of stolons, geniculately ascending, 30–60 cm tall, nodes glabrous or pubescent. Leaf sheaths compressed, keeled, shorter than internodes;leaf blades flat, 15–20 cm × 2.5–5 mm, glabrous or with a few hairs at base, margins smooth or scabrid, apex acuminate;ligule less than 1 mm, margin ciliate. Inflorescence terminal;peduncle glabrous;racemes (1–)2–4, 2.5–5 cm, with 1–3 pairs of homogamous spikelets. Sessile spikelet 3–3.5 mm;lower glume obovate-elliptic or obovate-oblong, papery, 8–12-veined, glabrous or often sparsely hirsute on lower back, slightly glossy, margins shortly ciliate, keels winged, apex rounded;upper glume ciliate above middle, apex obtuse;awn 1.5–2.5 cm, weakly geniculate. Caryopsis obovate-oblong. Pedicelled spikelet many-veined, resembling sessile (Flora of China Editorial Committee, 2015).
D. caricosum has been intentionally introduced as a perennial grazing pasture with excellent ground cover. Now, it can be found widely naturalized in tropical and subtropical regions (Cook et al., 2005;FAO, 2015). It has escaped from cultivation and has become a weed and invasive grass in Cuba, Guam, New Caledonia, and Fiji (MacKee, 1994;Oviedo Prieto et al. (2012);PIER, 2015). In Cuba, it is widespread across the islands. In Fiji, it covers large areas being very common especially in the dry zones, in pastures, canefields, waste places, and along roadsides (Smith, 1979). D. caricosum is a fast-growing gregarious grass that competes aggressively with other plants including other weeds (Cook et al., 2005).
D. caricosum is a common weed with negative impact in pastures and sugarcane fields (Smith, 1979).
The following description is from the Flora of China Editorial Committee (2017)
Medicago lupulina is an annual or short-lived perennial herb with a wide native range across Africa, Asia and Europe. It is a common weed in disturbed areas, wastelands, roadsides, abandoned pastures and forest margins. It is a nitrogen-fixing species cultivated for forage and used as a soil improver;it is also a seed contaminant of other crops. Currently, it is listed as invasive in the Philippines, Hawaii, New Zealand and a small number of islands in Oceania. However, there is limited information available about its environmental impact in these locations.
M. lupulina is listed as an agricultural weed of alfalfa, maize plantations and apple orchards (Vibrans, 2009).
M. pusilla is a perennial and annual herb, usually procumbent, many branched, 20-50 cm tall, scabrous. Stipule small, ovate-lanceolate, 4-6 × 2-3 mm;petiole 3-12 cm, stellate velutinous;leaf blade reniform, rarely 5-7-lobed, 1-3 × 1-4 cm, papery, abaxially sparsely stellate puberulent, adaxially sparsely velutinous, base cordate, margin minutely denticulate, apex rounded. Flowers usually 3-4-fascicled, axillary, rarely solitary on stem. Pedicel 2-5 cm, sparsely stellate puberulent. Epicalyx lobes lanceolate, 2-5 × 1-1.5 mm, stellate puberulent. Calyx campanulate, 5-6 mm, stellate puberulent, 5-lobed, lobes triangularly acuminate. Corolla white to pinkish, 10-12 mm in diameter;petals obcordate, 9-15 × 3-5 mm, apex notched;claw bearded. Filament tube stellate puberulent. Style branches 13-15. Fruit flat globose, 5-6 mm in diameter;mericarps 12-15, abaxially smooth, angles rounded, puberulent. Seeds reniform, approximately 1 mm in diameter, reticulate or not (Flora of China Editorial Committee, 2014).
M. pusilla is a cosmopolitan weed found principally in temperate regions of the world (Randall, 2012). It is a fast-growing, annual or perennial herb with the capacity to grow forming dense patches in gardens, yards, roadsides, waste ground, orchards, pastures and agricultural fields (Makowski and Morrison, 1989;DAISIE, 2014). M. pusilla is listed as invasive in Canada, the United States, and the Dominican Republic and in many countries in Europe (see distribution table for details;Kairo et al., 2003;DAISIE, 2014;USDA-NRCS, 2014).
M. pusilla is a weed of field crops including wheat, lentil, and flax, and in orchards and pasture lands principally in the United States and Canada (Steffey, 1980;Makowski and Morrison, 1989).
The following description is taken from Flora of China Editorial Committee (2015):
Annual grass, culms tufted, erect or geniculately ascending, slightly flattened, 15–100 cm tall. Basal leaf sheaths strongly keeled, glabrous;leaf blades flat or folded, 5–30 cm, 2–7 mm wide, glabrous, adaxial surface scabrous, apex acuminate;ligule 0.5–1 mm, glabrous or ciliate. Racemes digitate, 5–12, erect or slightly slanting, 2–10 cm, silky, pale brown or tinged pink or purple;rachis scabrous or hispid. Spikelets with 2 or 3 florets, 2-awned;lower glume 1.8–2.2 mm;upper glume 3–4 mm, acuminate;lemma of fertile floret obovate-lanceolate in side view, 2.8–3.5 mm, keel gibbous, conspicuously bearded on upper margins with a spreading tuft of 2.5–3.5 mm silky hairs, margins, keel and flanks silky-ciliate or glabrous;awn 5–15 mm;second floret sterile, oblong, glabrous, awn 4–10 mm;third floret occasionally present, reduced to a small clavate scale, awnless.
Chloris virgata is a widespread and very variable weedy annual grass (Flora of China Editorial Committee, 2015). This species is a particularly aggressive invader of bare areas and degraded or disturbed native vegetation, and it has the potential to out-compete native vegetation in these habitats (Smith, 2002;Oviedo Prieto et al., 2012;Weeds of Australia, 2015). This weedy grass spreads from cultivation, pastures, gardens, disturbed areas and roadsides to nearby disturbed forest, creeks and riversides, native grasslands and coastal habitats such as coastal forests and sand dunes (Weeds of Australia, 2015;FAO, 2015;PIER, 2015). It also grows as a weed in agricultural lands (Vibrans, 2009). Currently, this species is regarded as an invasive and environmental weed in northern Australia (i.e., Queensland and the Northern Territory;Weeds of Australia, 2015) and as an invasive grass in Cuba, Palau, New Caledonia, the Galapagos Islands, and Hawaii (Wagner et al., 1999;Charles Darwin Foundation, 2008;Oviedo Prieto et al., 2012;PIER, 2015).
C. virgata is a common weed in alfalfa (Medicago sativa) fields of the southwestern USA (Barkworth, 2003) and maize and sorghum plantations in Mexico (Vibrans, 2009).
Annual, biennial or short-lived perennial herbs, sparsely puberulent to glabrescent. Stems erect, 40-100(-250) cm, longitudinally ridged. Stipules linear-falcate, 3-5(-7) mm, entire or with 1 tooth at base;petiole slender;leaflets obovate, broadly ovate, oblanceolate, to linear, 15-25 (-30) × 5-15 mm, lateral veins running into teeth, 8-12 pairs, margins shallowly serrate. Racemes 6-15 (-20) mm, 30-70-flowered, dense at first, becoming lax in anthesis;bracts equal to pedicels, 1.5-2 mm. Corolla yellow, 4.5-7 mm;standard ± equal to wings and keel. Ovary narrowly ovate;ovules 4-8. Legume ovoid, 3-5 × 2 mm, veins transversely reticulate, dark brown, apex with persistent style. Seeds 1 or 2, yellowish brown, smooth, ovoid, 2.5 mm (Flora of China, 2017).
Melilotus officinalis is a herbaceous legume species, native to parts of Asia and possibly Europe (sources differ on this), that has been extensively introduced to be used as a forage and nitrogen-fixing crop. It has escaped from cultivation and become an invasive weed in many temperate and tropical regions;it can also be toxic to livestock. It is a prolific seeder, and its seeds can remain viable in the soil for many years. It is fast-growing and can grow in a wide range of environmental conditions. Like other nitrogen-fixing legumes, M. officinalis has the potential to alter soil conditions and nutrient cycling. It is allelopathic and so forms dense monospecific stands that displace and inhibit the establishment of native vegetation. In North America, infestations reduce the occurrence of natural fires and degrade native grassland communities that depend on frequent fires. In Alaska and Canada, this species is a serious problem on waterways because it is invading glacial river floodplains. Currently, it is recognized as a conservation problem in North America because it is invading critical natural areas such as national parks and protected lands.
Melilotus officinalis is listed as a weed in farmlands and grasslands in China (Chen et al., 2009). More specifically, in North America it is listed as a problematic weed in canola (oilseed rape) and wheat fields (Turkington et al., 1978;Conn and Seefeldt, 2009).
The following text is adapted from the Flora of China Editorial Committee (2015). P. arenastrum has procumbent or ascending stems, 15-30 cm tall, branched from base. Petiole is short, articulate at base. Leaf blade is elliptic or oblanceolate, 0.5-2 cm × 2-5 mm, both surfaces with conspicuous veins, base narrowly cuneate, margin entire, apex usually obtuse;ocrea white, 2-3 mm, membranous, 5-7 veined, lacerate. Flowers 3-5, grow in axillary fascicles;with narrowly ovate bracts and acute apex. Pedicel articulate at apex. Perianth is green, 5-cleft to 1/2, veined, margin white;tepals oblong. Stamens 8;filaments dilated at base. Styles 3, very short;stigmas capitate. Achenes (one-seeded fruit that does not open to release the seed) are included in persistent perianth, dark brown, opaque, narrowly ovoid, trigonous, rarely biconvex, 2-2.5 mm, densely minutely granular striate.
P. arenastrum is an annual species native to Eurasia. It is found in field and row crops, orchards, yards, gardens and turf. It readily invades areas compacted by trampling with foot traffic and is therefore frequently found along roadsides, sports fields, vacant lots, gravel parking areas and walkways. This species establishes a taproot, which allows it to survive periods of drought. As a result it can compete with agricultural crops for water and nutrients reducing yields. In California it is reported to have a negative impact on the threatened species Arenaria ursina [ Eremogone ursina ]. P. arenastrum is considered as an environmental weed in parts of Australia and an agricultural weed in cropping systems in Australia and Canada.
Smith et al. (2008) note that P. arenastrum is troublesome in agricultural fields, in particular in alfalfa fields (Medicago sativa), where soil is compacted from wheel traffic.
Description from Flora of China Editorial Committee (2017)
Themeda quadrivalvis is an annual grass found as a weed in grasslands, disturbed areas and agricultural land. It is native to the Indian Subcontinent and South East Asia but has been widely introduced to the Americas, Africa and Oceania. It is recorded as invasive in Mexico, Cuba, Dominican Republic, Reunion, Australia, Fiji and New Caledonia. It is spread unintentionally as a contaminant in straw packing, pasture seed and on vehicles and machinery. Once established, it forms dense thickets that prevent seedling establishment;this causes ecosystem change, altered fire regimes and reduced native biodiversity.
T. quadrivalvis has become an aggressive weed in sugarcane fields, citrus orchards and pastures and also in lucerne and other legume seed crops (Smith, 2002;FAO, 2017;Weeds of Australia, 2017).
P. chinensis is a perennial herb. Rhizomes stout. Stems erect, 70-100 cm tall, ligneous at base, much branched, striate, glabrous or retrorsely hispid. Petiole 1-2 cm, usually auriculate at base, upper leaves subsessile;leaf blade ovate, elliptic, or lanceolate, 4-16 × 1.5-8 cm, both surfaces glabrous or hispid, abaxially sometimes pubescent along veins, base truncate or broadly cordate, margin entire, apex shortly acuminate;ocrea tubular, 1.5-2.5 cm, membranous, glabrous, much veined, apex oblique, not ciliate. Inflorescence terminal or axillary, capitate, 3-5 mm, usually several capitula aggregated and panicle-like;peduncle densely glandular hairy;bracts broadly ovate, each 1-3-flowered. Perianth white or pinkish, 5-parted;tepals ovate, accrescent in fruit, becoming blue-black, fleshy. Stamens 8, included. Styles 3, connate to below middle. Achenes included in persistent perianth, black, opaque, broadly ovoid, trigonous, 3-4 mm (Flora of China Editorial Committee, 2014).
P. chinensis is closely related to other important invasive Persicaria species such as P. orientalis, P. capitata, and P. perfoliata, all species included in the Global Compendium of Weeds (Randall, 2012). P. chinensis is a fast-growing herb that forms dense mats and tolerates diverse environmental conditions (Galloway and Lepper, 2010). It spreads by seed and by resprouting from broken fragments. Its high growth rates and spread potential provides this species the ability to smother other plants affecting plant community structure and composition (USDA-APHIS, 2012). Biosecurity New Zealand described the species in a risk assessment as “a highly invasive plant that quickly smothers available surfaces including other plants and trees,” and PIER (2014) lists it as invasive in several territories, including Hawaii.
P. chinensis is a common weed requiring control in tea plantations where it covers tea bushes and blocks drainage systems (Tjitrosemito and Jaya, 1990).
Erect herbs to about 2 m high, the stems slender, sparsely strigillose or glabrate;lower leaves opposite, the upper alternate, petiolate, the blades ovate to rhombic-ovate or lanceolate, mostly 3-12 cm long, acute to long-acuminate, cuneate or attenuate to the petiole, the margins serrate, serrulate, or subentire, strigillose and usually scabrous above, beneath strigillose to densely soft-pilose;inflorescences pedunculate;heads on pedicels mostly 2-8 cm long, disposed in lax, open, cymose panicles;disc of the head 7-10 mm long, 10-14 mm broad;involucres broadly campanulate, 5-10 mm high;phyllaries 3-seriate, lance-ovate or ovate-oblong to linear or linear-oblong, acute or acuminate, herbaceous, spreading or appressed, hispidulous or densely appressed-pilose;ray flowers 10-12, the ligules yellow, 7-15 mm long;disc corollas yellow, more or less hirtellous, 3-4 mm long;achenes obovate-oblong, black or mottled, appressed-pubescent, 3-4 mm long;pappus a crown of fimbriate squamellae less than 1 mm long and 2 slender, unequal awns, 2.2- 2.8 mm long (Nash, 1976).
V. dentata is an erect herb listed as an invasive species only in Cuba (Oviedo Prieto et al., 2012). On this island, the species grows as an invasive weed in cultivated plots as well as in disturbed sites and ruderal areas. V. dentata also grows as a weed in ruderal areas and thickets within its native distribution range of Mexico and the USA (Vibrans, 2009;Flora of North America Editorial Committee, 2014;USDA-NRCS, 2014).
The entire plant is sticky, hairy and odorous (Mitich, 1992), with coarsely toothed or pinnatifid leaves that may be long petiolate or sessile and decurrent (Hocking, 1947;Williams, 1960). Depending on growing conditions and variety, the plant averages between 0.75 and 1.5m tall. The annual variety may be early or late flowering and germinates, blooms and dies during a single season. In the biennial variety, a tuber derived from the hypocotyl and the upper portion of the root (Lang, 1986) develops in the first year, giving the entire root the resemblance of a parsnip root. Sessile, yellowish-brown and purple-veined campanulate flowers are borne in several indeterminate scorpoid cymes (Halevy, 1986). The fruit, a pyxis (urn-shaped capsule with a lid-like top), dehisces to release hundreds of black/grey seeds (Hocking, 1947;Whitson et al., 2000). For further detailed descriptions of H. niger, see also Gibson (1964) and LaFantasie (2008).
In the field, H. niger has a distinctive shape upon flowering, and developing a search image would not take much time. Surveying fields and monitoring points of entry would benefit from the use of photos, descriptions and keys, including Weeds of the West (Whitson et al., 2000), Flora of the Northeast (Magee and Ahles, 1999) and Flora of China (Flora of China Editorial Committee, 2015). An excellent description of seed characteristics can be found in Shahid Farooq and Khan (1996);however, seed size (1.5 mm long) may make detection difficult.
Hyoscyamus niger, an annual or biennial herb growing up to 1.5 m tall, is thought to have been native originally to a broad region of Eurasia. It is naturalized in many regions globally and is a noxious weed in much of North America. H. niger is cultivated as a medicinal plant in many countries, and risk of introduction is likely to be associated with commercial seed or as a seed contaminant. Once established, H. niger is capable of producing thousands of highly viable seeds per plant. However, its competitive ability appears to be limited to disturbed and cultivated areas.
The presence of H. niger in hay affects hay quality. It is a weed of several crops, including wheat, millet and cotton (AgroAtlas, 2015), and of pastures.
The description of B. japonicus given by the Flora of China Editorial Committee (2016) states:
Annual. Culms erect, 40–90 cm tall. Leaf sheaths pubescent;leaf blades 12–30 cm × 4–8 mm, both surfaces pubescent;ligule 1–2.5 mm. Panicle effuse, 20–30 × 5–10 cm, nodding;branches 2–8, 5–10 cm, slender, each bearing 1–4 spikelets. Spikelets lanceolate-oblong, 12–20 × ca. 5 mm, yellowish green, florets 7–11, closely overlapping;rachilla internodes shortly clavate, ca. 2 mm;glumes subequal, keel scabrid, margins membranous, lower glume 5–7 mm, 3–5-veined, upper glume 5–7.5 mm, 7–9-veined;lemmas elliptic, 8–10 × ca. 2 mm in side view, herbaceous, 9-veined, usually glabrous, margins membranous with conspicuous angle at maturity, scabrid, apex obtuse, minutely 2-toothed, awned from 1–2 mm below apex;awn 5–10 mm, longer on upper lemmas than lower lemmas, base slightly flattened, conspicuously recurved at maturity;palea shorter than lemma, ca. 1 mm wide, keels stiffly ciliate. Anthers ca. 1 mm. Caryopsis 7–8 mm. Fl. and fr. May–Jul. 2n = 14.
B. japonicus has relatively greater root development than B. tectorum (Hulbert 1955).
Wang et al. (1999) described a spectral-based sensor for detection and discrimination of wheat and weeds such as B. japonicus.
B;japonicus is an annual grass, originating in Eurasia and Northern Africa, which is introduced and invasive in rangelands in central and western North America, and a weed in wheat and other annual crops. It is an aggressive species that out-competes desirable vegetation for water and soil nutrients, thus reducing plant biodiversity. Invaded communities have reduced native vegetation cover and lower species richness than native rangelands. Seeds can remain viable in the soil for several years, making control difficult. B. japonicus is listed as a significant threat in Kentucky (Kentucky Exotic Pest Plant Council, 2013), is invasive in California (California Invasive Plant Council, 2016), and has an ‘Alert’ status in Tennessee (Tennessee Exotic Pest Plant Council, 2009). In Canada, it is listed as a noxious weed in Alberta and Saskatchewan.
Adapted from Flora of North America Editorial Committee (2014)
Russian thistles or tumbleweed of the genus Salsola are annual weeds, mostly native to Europe and Asia, but introduced globally. Salsola infests many tens of millions of hectares, especially in North America. S. paulsenii is a coarse, spiny annual weed native to Central Asia and introduced to North America. It tends to be found in drier and more lowland desert areas in the western USA as compared to other weedy Salsola species, with which it is often confused. S. paulsenii can be controlled by cultivation and chemicals, and a number of biological control agents have been tested. However, it is likely to remain a troublesome weed unless biocontrol eventually offers a viable option.
Slightly modified from Flora of North America (2013)
P. persicaria is a species of knotweed native to the Americas. It has been introduced, presumably accidentally, to New Zealand, Pakistan and Hawaii, where it is found in shallow water, shores, marshes, swamps, the borders of ponds and small streams, drainage ditches and floodplain forests.
The following has been adapted from Wilken and Hannah (1998), Hoban and Hoshovsky (2000), Flora of North America (2016) and the Encyclopedia of Life (2016).
E. glomerata is a perennial herbaceous plant in the Asteraceae that is native to Australia and New Zealand and has become naturalised in northwestern USA (in the states of Washington, Oregon and California). It is considered a problem invader in the Channel Islands, California, USA. It is able to quickly colonise and dominate disturbed areas such as those cleared by logging activity or fire. Along with other non-natives, it is potentially threatening native species in California.
N. peltata is an aquatic, bottom-rooted perennial plant with round, floating leaves, yellow flowers borne upon peduncles rising above the water's surface, and long branching stolons with adventitious roots beneath the water’s surface. The circular to slightly heart shaped floating leaves are 3-15 cm in diameter on long stalks that attach to underwater rhizomes. The floating leaves have slightly wavy, scalloped margins and are alternately arranged at the stem base but are opposite at the apex (Flora of China, 2002). They are a green to yellow-green colour above, and are often a purple colour on the underside of the leaf. Each peduncle that rises a few inches above the water surface can have two to five flowers, which are bright yellow, have five distinctly fringed petals, and are 3-4 cm in diameter. Both long- and short-styled flower morphs are usually needed to sexually reproduce (Ornduff, 1966). The fruit is a 1.2-2.5 cm beaked capsule that contains many flat, smooth, ovoid seeds with winged margins. The seeds are approximately 0.4 mm thick, 3.8-5.1 mm long, and 2.7–3.0 mm broad (Cook, 1990). The seeds also have winged margins which aid attachment to avian vectors and floatation (Cook, 1990).
N. peltata is an aquatic, bottom-rooted perennial plant with floating leaves, which can grow in dense mats and reproduce prolifically through both vegetative and sexual means. These dense mats have caused many negative environmental and economic impacts, which include displacing native species, reducing biodiversity, decreasing water quality, impeding recreational activities, and diminishing aesthetic value. N. peltata is very difficult to control due to its ability to form a new plant from rhizomes, stolons, separated leaves, or seeds. The dispersal of N. peltata to new locations may be aided by the transport of seeds by avian vectors (Cook, 1990);however, the trade and potential escape of N. peltata through the water garden industry may play a larger role in its spread (Les and Mehrhoff, 1999). N. peltata is declared a noxious weed in New Zealand and parts of North America (NWCB, 2007), and is also declared as invasive in Sweden (Gren et al., 2007). Other species of Nymphoides also have the potential to become invasive, and N. indica and N. cristata have been recorded as problematic in Florida, USA.
The following description is from Flora of China Editorial Committee (2012)
M. vimineum impedes regeneration of native woody species and lowers overall species diversity and stem densities (Oswalt et al., 2007). One study found that it inhibited the success of small-seeded trees and reduced tree survival after one growing season by more than 20%, negatively impacting on Acer negundo (box elder), Platanus occidentalis (sycamore) and Liriodendron tulipifera (tulip poplar) (Flory and Clay, 2010).
S. cayennensis is a perennial evergreen herb or subshrub which can reach heights of 2.5 m. It has a woody glabrous stem with several branches. Leaves opposite, membranous, elliptic to broadly elliptic or ovate, 4-8 cm long, 2-4.5 cm wide, upper surface rugose, both surfaces glabrous or occasionally lower surface with a few scattered hairs usually along the veins and margins, margins sharply and coarsely serrate, the teeth conspicuously divergent, apex acute, base cuneate, petioles 0.5-2 cm long. Spikes slender, rachis flexuous to erect or somewhat nodding, 14-40 cm long, ca. 2.5 mm in diameter, the furrows somewhat shallow, nearly as wide as the rachis, bracts lanceolate, ca. 7 mm long;calyx ca. 7 mm long, the teeth subequal;corolla usually dark purplish blue with a paler center, the tube 7-8 mm long (Wagner et al., 1999).
S. cayennensis is a shrub native to South and Central America and the Caribbean. It was introduced widely introduced into several tropical countries around the world as an ornamental species due to its attractive blue flowers, but in some countries it has become invasive. S. cayennensis has a wide environmental tolerance and often invades disturbed areas where it can outcompete native flora. It is invasive in many Pacific islands and is regarded as a noxious weed in the Northern Territory, Australia and is increasing in abundance in Florida, USA. According to a risk assessment this species is regarded as being highly invasive (score 20 = high risk) (PIER, 2015).
S. cayennensis may outcompete smaller native plant species and crops dedicated to livestock are often affected by smothering. In Australia, this species is commonly found as a weed of pastures and sugarcane (Saccharum species) (DAFF, 2014).
Annual herbs, 10-40 dm tall;stems simple below, branching above, tomentose when young. Leaves usually lanceolate in outline, with deeply sinuate or lobed, spiny margins;lower surface whitish tomentose. Lower leaves up to 45 cm long and 18 cm wide, with long decurrent base, upper leaves to 10 cm long and 6 cm wide, truncate or lyrate. Inflorescence of terminal clusters of 3-5 or single heads on short peduncles arising from the axils of the upper and middle leaves. Heads with the involucre 8- or 9-seriate, 3-3.5 cm tall, 1.5-2 cm in diameter at the base, the outer involucral bracts 4-6 mm long, basally 1-2 mm wide, with a glutinous dorsal ridge, tapering to a 5-7 mm long spine, the innermost bracts 25-35 mm long, 1-2 mm wide, tapering, twisted and often purple near the tip;corolla purple to reddish, 26-30 mm long, the lobes 4-5 mm long, anthers colourless, 4-5 mm long, style purple 27-31 mm long. Achenes 4-5 mm long, 1-1.5 mm in diameter;pappus 23-25 mm long (Flora of Panama WFO, 2013).
C. mexicanum is a cosmopolitan herb included in the Global Compendium of Weeds (Randall, 2012). This species has been classified as invasive in Cuba (González-Torres et al., 2012) and Puerto Rico, and as an agricultural and environmental weed within its native distribution range which includes Mexico and Central America (Randall, 2012). This species is a fast-growing herb which spreads by seeds and produces a large number of bristled seeds which can be easily dispersed by wind (Pruski, 2013).
C. mexicanum is listed as a weed which principally affects active pastures. In these areas, rosettes can grow forming dense monospecific stands. Previous studies have suggested that cattle do not feed on these plants (Cardenas and Coulston, 1967).
The following description has been adapted from the Flora of North America Editorial Committee (2016).
Aminidehagui et al. (2006) noted that L. perfoliatum has allelopathic effects on the roots of lettuce (Lactuca sativa).
Herbaceous, perennial vine;branching stem obscurely 6-angled to terate, ranging from glabrous to densely pilose;8-15 cm internodes. Petioles glabrous or puberulent, 20-50 mm. Triangular to triangular-ovate leaf blades, 3-15 x 2-11 cm with cordate to hastate bases;margins subentire to undulate, crenate, or dentate, apices acuminate (tips often caudate), faces puberulent. Produces dense corymbiform flowers, with small heads 5-7 mm long. Corollas generally pinkish to purplish, occasionally white, 3-5.4 mm, dotted sparsely with glands, lobes triangular to deltate. Cypselae dark brown to blackish, 1.8-2.2 mm, also dotted with glands;pappi of 30-37 white or pinkish to purplish bristles 4-4.5 mm. Fruits are oblong 1-.5-2.5 mm long, brownish black, five angled resinous achenes;Chromosome number 2n=38 (Holm et al., 1991;Flora of North America Editorial Committee, 2013).
The following description is adapted from Flora of North America Editorial Committee (2015).
A. semibaccata is a low-growing shrub native to Australia. It is valued as a fodder plant and, along with many other Atriplex species, has been introduced around the world as a drought and salt tolerant forage. It was introduced to the USA where it has escaped cultivation and is now invasive in coastal grasslands, scrub and saline area, where it can form a dense cover inhibiting the growth of native plants. The California Invasive Plant Council classifies its potential impact on native ecosystems as moderate and control and eradication of this species appears possible. Many other Atriplex species are beginning to be reported as somewhat invasive in other parts of the world and the genus merits further attention in this regard.
The following description is adapted from Miller (1988) and Flora of Panama (2018)
Heliotropium curassavicum is an aggressive weed that rapidly colonizes new areas, in particular on disturbed saline soils and coastal areas in arid and semiarid habitats. It forms dense monospecific stands that displace native vegetation and alter successional pathways. A combination of traits, such as high seed germination and seedling establishment rates in open areas, along with its ability to shift between sexual reproduction to clonal growth (i.e., adventitious root buds) are responsible for the invasiveness and rapid spread of H. curassavicum. H. curassavicum has become one of the most common weeds in the Mediterranean Basin and the Nile Delta, where it is regarded as a serious ecological and agricultural problem, but it is also listed as invasive in countries across Europe, the Arabian Peninsula, Africa and in Anguilla in the Lesser Antilles.
H. coccineum is a vigorous perennial herb. Pseudostems grow up to 1.5-2 m height. Leaves sessile;ligule 1.2-2.5 cm;leaf blade narrowly linear, 25-50 × 3-5 cm, glabrous, base subrounded or attenuate, apex caudate-acuminate. Spikes cylindric, usually dense, glabrous or sparsely villous;bracts oblong, 3-3.5 cm, leathery, sparsely pubescent, rarely glabrous, 3-flowered, margin involute or rather flat, apex obtuse or acute. Flowers red. Calyx ca. 2.5 cm, sparsely pubescent especially at 3-toothed apex. Corolla tube slightly longer than calyx;lobes reflexed, linear, ca. 3 cm. Lateral staminodes lanceolate, ca. 2.3 cm. Labellum orbicular, ca. 2 cm wide or rather small, apex deeply 2-cleft. Filament ca. 5 cm;anther 7-8 mm. Ovary sericeous, 2.5-3 mm. Capsule globose, approximately 2 cm in diameter. Seeds red. (Flora of China Editorial Committee 2012).
Hedychium coccineum is an adaptable, tall, herbaceous, and very variable ornamental plant native to Asia. It can colonise natural or semi-natural habitats, from riverine fringe and mountain grasslands to forest understorey. In its introduced range, it can become dominant or co-dominant in natural or semi-natural environments, competing with and displacing indigenous species (e.g. in La Réunion, Africa;Brazil;South Africa). Similarly to other Hedychium species (i.e., Hedychium gardnerianum and H. coronarium), it is widely traded as a garden ornamental around the world. H. coccineum is included in the Global Invasive Species Database (2014) and the Global Compendium of Weeds (Randall, 2012) and is a declared weed and invasive species in some countries. Its environmental adaptability, high commercial appeal and growing impact in countries where it has established suggest its prospective spread in delicate ecosystems cannot be underestimated.
Infestations of H. coccineum have been reported in plantations in South Africa as well as limited access to plantations caused by the plant (Henderson, 2001).
Structurally, the Lemnaceae are the simplest of the flowering plants. The plants are not differentiated into stems and leaves;instead, the plants in the family have an undifferentiated leaf-like body commonly referred to as a frond. Fronds floating, 1 or 2-few, coherent in groups, obovate, flat to thickish (but not gibbous), 0.8-4 mm, 1-2 times as long as wide, margins entire and thin, usually pale green, shining, nearly always with a sharp ridge with white papillae;veins 1, sometimes indistinct, very rarely longer than extension of air spaces, not longer than 2/3 of distance between node and apex;with or without small papillae along midline;anthocyanin absent;largest air spaces much shorter than 0.3 mm;turions absent. Roots to 1.5 cm, tip rounded to pointed, one root per frond;sheath not winged. Stipes (stalks) white, small, often decaying. Flowers within membranous cup-like spathes (open on one side) inside budding pouches located on either side of the basal end. Ovaries 1-ovulate, utricular scale open on 1 side. Fruits 0.6-1 mm, not winged. Seeds with 12-15 distinct ribs (Landolt, 1980;Flora of North America, 2008;Armstrong, 2009).
L. minuta is a small free-floating plant, no more than 3 mm in length. It is widely distributed in southern and western North America and is also found in Central and South America. It occurs in lowland ditches, ponds, canals, streams and rivers, and more rarely it is found in lakes (Preston and Croft, 1997). It often forms dense mats on the surface of water, reducing the light penetration and gas exchange, often causing the disappearance of submersed aquatic plants. Outbreaks are usually limited in time and space and are favoured by eutrophication. L. minuta is introduced in Eurasia (Landolt 2000) and it was first recorded in western France in 1965. From there it has spread all over Europe as far as southern Russia and Greece. It is also present in Japan (e.g. Landolt, 1986). It is considered a casual alien by Global Compendium of Weeds (2007). In many areas it is a noxious weed, as in Belgium, and it is included in the watch list with moderate impact (Branquart et al., 2007).
S. minima is a deep-green, free-floating, rootless, aquatic fern (ISSG, 2006). Stems can be up to 6 cm and leaves are from 1-1.5 cm long and almost round to elliptic. They are obtuse or notched at the apex and round to heart-shaped at the base. The upward surfaces of the fronds are covered with stiff hairs, with four separated branches. The under surface of the leaves are brown and pubescent with slender and unbranched hairs (Flora of North America Editorial Committee, 1993). The stiff hairs on the fronds serve to trap air, thus providing buoyancy (Dickinson and Miller, 1998). Obscure veins are areolate and do not quite reach to the leaf edges. Sporocarps occur in groups of four to eight, with up to 25 megasporangia (Flora of North America Editorial Committee, 1993).
S. minima is free-floating, which makes it easier to identify than most submerged aquatic vegetation. Volunteer monitors should be trained on the identity and habit of this potential invader.
S. minima is a very productive free-floating, non-rooted aquatic fern native to South and Central America. It was introduced outside its native range in southern Florida, USA in 1926 (USGS, 2005). The plant is degrading wetland ecosystems in several states of the USA (Tipping and Center, 2005). S. minima has an extremely high reproductive potential;the plants can rapidly colonize bodies of water, forming thick mats that displace native species, impact water quality, impede recreational activities, and clog waterways and irrigation channels (Rayachhetry et al., 2002). S. minima is also resistant to desiccation, allowing it to be transported long distances out of water (ISSG, 2006). The species can act as an annual, dying back when temperatures decrease and causing harmful nutrient pulses and dissolved oxygen crashes (Dickinson and Miller, 1998).
S. minima is a highly competitive species with a very high growth rate. Colonies of S. minima can grow very densely, such that they shade light from valuable native submerged aquatic plant species (USACE-ERDC, 2002). Dense colonies can thus decrease local biodiversity and degrade the habitat (ISSG, 2006). The plant is also highly competitive among other free-floating species. A competition study specifically showed that S. minima had negative effects on the change in cover of the species Azolla caroliniana and Spirodela punctata (Dickinson and Miller, 1998). In Louisiana, USA native Lemna species were completely replaced by S. minima (ISSG, 2005).
The following description is from Flora of Panama (2016)
S. linifolia is an herb or small shrub reported as invasive to Cuba and Hawaii, USA (Oviedo Prieto et al., 2012;PIER, 2016). No details are given on its invasiveness or the effects on habitats and/or biodiversity. Although it is listed as invasive for Hawaii by PIER (2016), it also is noted as “not common”.
The species occurs as a weed in cultivated land and plantations (Fariñas et al., 2011;JIRCAS, 2016). It is one of the species affected by the Okra Mosaic Virus strain, NIN-OKMV, and could be a source of infection for some crops (Igwegbe, 1983).
The species is a creeping annual or short-lived perennial plant. Culms slender, straggling, rooting at lower nodes, 20Ð60 cm tall, nodes pubescent (Flora of China Editorial Committee, 2015). The leaf blades are broadly linear to narrowly lanceolate, loose, glabrous or with tubercle-based hairs or ciliate margins, 2Ð8 cm long, and 3Ð7 mm wide. Leaf base subrounded, margins thicker and scabrous, apexacute or acuminate. Ligule a fimbriated membrane, few long hairs on shoulders. Inflorescences produce 2Ð3 racemes borne on a 0.5Ð2 cm long axis, unilateral, 2-6 cm long. Central inflorescence axis 3-10 cm long. Rachis narrowly winged, glabrous on margins, with very short scabrous hairs. Racemes are 1Ð3 cm long, bearing the spikelets on a narrowly winged rachis. Spikelets are narrowly elliptic, 2.4Ð3 mm long, glabrous, and acute, or 3.3-3.7 mm long, and slightly dorsally compressed. Spikelet packing adaxial, regular, 2 -rowed. Spikelets solitary. Fertile spikelets sessile, comprised of a basal sterile floret and a fertile floret, there is no rhachilla extension, and they fall entire. Rhachilla internodes elongated between glumes. Glumes dissimilar and reaching apex of florets, thinner than fertile lemma. The lower glume is ovate, 1/3Ð1/2 as long as the spikelet, clasping, membranous, without keels, 5-7-veined. Lower glume with obtuse apex, upper glume apex acute, oblong, separated from the lower by a short internode. Upper lemma rugulose, margins involute, bluntly acute. Lemma of lower sterile floret similar to upper glume, oblong, equal length of spikelet, membranous, 5 -veined, acute. Fertile lemma elliptic, 3-3.5 mm long, indurate. Basal sterile florets barren, with palea involute, indurate, surface rugose. Fruit testa glossy, with dense low papillae. Rhizomes absent. Stolons absent or present.
T. fragrans is an herbaceous vine, twining, 2-3 m in length. Stems cylindrical, striate, slender, puberulous. Leaves opposite;blades 6.5-11 × 1.8-6 cm, ovate to lanceolate, chartaceous, the apex acute, the base truncate or subcordiform;margins undulate and ciliate;upper surface dark green, glabrous or somewhat scabrous;lower surface pale green, dull, puberulous, with prominent venation;petiole 2-3.5 cm long, slender, pubescent, sulcate, with the base somewhat dilated. Flowers axillary, solitary or in pairs;pedicels pubescent, 5-7 cm long, striate;bracts green, membranaceous, ovate, pubescent, 1.6-2 cm long, covering the calyx. Calyx green, of 15-20 sepals, lanceolate, 3-5 mm long;corolla white, infundibuliform, with 5 lobes, the tube 2.5-4 cm long, narrow at the base, yellow inside, the limb 4-5 cm in diameter. Capsules 1-2.5 cm long, depressed-globose at the base, the upper half in the form of a beak, dehiscent in two halves;seeds 4, globose, approximately 5 mm in diameter, pubescent, with a depression at the base (Acevedo-Rodríguez, 2005). Variation in the shape, size, pubescence, and margin form of the leaves is extensive in T. fragrans, and taxa have been recognized based on these characters (Flora of China Editorial Committee, 2014).
T. fragrans is an herbaceous fast-growing vine widely cultivated as an ornamental in tropical and subtropical regions of the world, but it is also a common weed in moist disturbed areas, in particular along roadsides (Starr et al., 2003;Randall, 2012). In most cases, this species has been intentionally introduced as an ornamental and it has escaped from cultivation and naturalized in both relatively unaltered and disturbed forests, riversides, roadsides and urban bushland (Starr et al., 2003;Meyer and Lavergne, 2004;Queensland Department of Primary Industries and Fisheries, 2011). T. fragrans is included in the Global Compendium of Weeds where is listed as an “environmental weed,” and it is also listed as invasive in Australia, Japan, Singapore, Cuba, Puerto Rico, Hawaii and French Polynesia among others (Meyer and Lavergne, 2004;Mito and Uesugi, 2004;Chong et al., 2009;Queensland Department of Primary Industries and Fisheries, 2011;Oviedo-Prieto et al., 2012;PIER, 2014).
The following has been adapted from Flora of China Editorial Committee (2016) and Flora of North America Editorial Committee (2016).
B. hyssopifolia is an annual herb mostly found in arid and semi-arid habitats. It is native to Eurasia but has been introduced to North America, South America, Hawaii, Australia and parts of Europe. The species can become dominant on alkaline soils where there is little competition from other plant species. It is especially problematic in the southwestern USA, where it is toxic to some livestock, and is readily dispersed as the hooks on ripened fruit attach to animal fur, and it has proven to be a threat to some endangered plant and animal species in the USA.
Herbs succulent. Stems short, suckering freely to form dense clumps. Leaves sub-basal, slightly distichous in seedlings and new shoots, erect, pale green, sometimes with pale spots in very young plants, linear-lanceolate, 15-35(-50) ? 4-5(-7) cm, margin sparsely spiny-dentate, apex 2- or 3-dentate-pointed. Inflorescence erect, 60-90 cm;peduncle to 2 cm thick;raceme 30-40 ? 5-6 cm, sometimes with 1 or 2 ascending branches, numerous flowered;bracts whitish, broadly lanceolate, 10 ? 5-6 mm, veins 5-7, apex acute. Flowers reflexed;pedicel 1/2 as long as bract. Perianth pale yellow mottled with red, slightly ventricose, 2.5(-3) cm, outer lobes free for 1.8 cm, slightly recurved at apex. Stamens exserted by 4-5 mm. Style conspicuously exserted (Flora of China Editorial Committee, 2017).
The following description of R. laciniata is taken from the Flora of North America (2015)
R. laciniata is a perennial plant native to central and eastern North America that has been introduced around the world for ornamental purposes. In some introduced areas it is considered an agricultural and environmental weed as it can form dense monocultures which can outcompete and reduce native biodiversity. R. laciniata reproduces by producing a large number of seeds which can remain viable in the soil for at least three years and it can also regenerate from rhizome fragments. This makes control of this species difficult. R. laciniata is classified as an Alien Invasive Species under the Japanese Invasive species Act and is also noted as invasive in Europe.
F. benghalensis is a large, evergreen to deciduous tree, up to 20 (-25) m tall, with wide leafy crown and branches spreading up to 100 m or more with pillar-like prop roots and accessory trunks. Trunk massive, fluted, bark grey, smooth, young softly white puberulous. Leaves with stout, (1.5-) 2-6 (-8) cm long, ventrally compressed hairy petiole;lamina coriaceous, ovate or obovate to elliptic, (8-) 10-20 (-25) cm long, (6-) 8-15 (20) cm broad, glabrous above, finely pubescent beneath, base subcordate or rounded, margins apically obtuse, lateral nerves 4-7 pairs, intercostals distinct, ± bulging stipules coriaceous, stout, 1.5-2.5 cm long, acute;cystoliths abundant on side, few or absent below. Hypanthodia sessile, in axillary pairs on young depressed-globose, 15-2 cm in diameter, green, hairy, subtended by 3, reniform c. 3-4 mm long, c. 6-7 mm wide, minutely hairy basal bracts, apical orifice by 3, flat or ± umbonate bracts, internal bristles absent. Male flowers: numerous ostiolar, shortly pedicellate;sepals 2-3;stamen solitary, with shortly mucronate anther. Female flowers: sessile, mixed with gall flowers;sepals 34, small;ovary with an elongated style. Gall flowers numerous, pedicellate;sepal as in female ovary with a short style. Figs globose to depressed-globose, 15-2.5 cm in diameter pinkish-red, hairy (Flora of Pakistan, 2014).
Trees, 15-25 m tall, d.b.h. 30-50 cm, epiphytic when young, crown wide when mature. Bark gray, smooth or longitudinally ± fissured. Branchlets grayish brown, sparsely pubescent when young. Stipules ovate, small, apex acute. Petiole slender, as long as or longer than leaf blade, articulate, leaf blade triangular-ovate, 9-17 x 8-12 cm, leathery, abaxially green, adaxially dark green and shiny, base broadly cuneate to ± cordate, margin entire or undulate, apex acute to caudate with a 2-5 cm cauda, basal lateral veins 2, secondary veins 5-7 on each side of midvein. Figs axillary on leafy branchlets, paired or solitary, red when mature, globose to depressed globose, 1-1.5 cm in diameter, smooth, peduncle 4-9 mm, involucral bracts ovate. Male, gall, and female flowers within same fig. Male flowers: few, near apical pore, sessile, calyx 2- or 3-lobed, margin revolute, stamen 1, filament short. Gall flowers: pedicellate, calyx 3- or 4-lobed, ovary globose, smooth, style short, stigma enlarged, 2-lobed. Female flowers: sessile, calyx 4-lobed, broadly lanceolate, ovary globose, smooth, style thin, stigma narrow. [Flora of China Editorial Committee, 2014]
Perennial subshrub, woody at base, up to 1 m tall, usually with white latex and an unpleasant smell, roots up to 70 cm long, stems narrowly winged, green or red, shortly hairy to glabrous, often woody at base. Leaves decussately opposite, simple and entire, stipules 2Ð4 at each side of the leaf base, petiole 3Ð11 mm long, green or red, blade elliptical to obovate or narrowly obovate, 2.5Ð8.5 cm ? 1Ð4 cm, base cuneate, apex obtuse or acute with a mucronate tip, herbaceous to thinly leathery, glossy green above and pale green below, sparsely shortly hairy to glabrous on both sides. Inflorescence terminal, but apparently lateral, 1Ð2-flowered. Flowers bisexual, 5-merous, regular, almost sessile, sepals slightly fused at base, (2Ð)3Ð5 mm long, erect, green, corolla tube cylindrical, 2Ð3 cm long, widening near the top at the insertion of the stamens, laxly shortly hairy to glabrous outside, with a ring of hairs in the throat and another lower down the tube, greenish, lobes broadly obovate, 1Ð2(Ð3) cm long, apex mucronate, glabrous, spreading, pink, rose-purple or white with a purple, red, pink, pale yellow or white centre, stamens inserted just below the corolla throat, included, filaments very short, ovary superior, consisting of 2 very narrowly oblong carpels, style slender, 15Ð23 mm long, with a cylindrical pistil head provided at base with a reflexed transparent frill and with rings of woolly hairs at base and apex, stigma glabrous. Fruit composed of 2 free cylindrical follicles 2Ð4.5 cm long, striate, laxly shortly hairy to glabrous, green, dehiscent, 10Ð20-seeded. Seeds oblong, 2Ð3 mm long, grooved at one side, black (Flora of China Editorial Committee, 2015, PROTA, 2015).
Trees about 15 m tall;bark grayish brown;branchlets, petioles, and inflorescences densely yellow-brown tomentose. Branchlets slightly 4-angled when young, becoming terete, lenticellate, leaf scars prominent. Petiole terete, 3.5-10 cm;leaf blade broadly ovate, 8-19 X 4.5-15 cm, thickly papery, base broadly cuneate to subcordate, apex acuminate;veins 3-5 pairs, abaxially prominent. Inflorescences terminal, narrow thyrses;peduncle 15-30 cm. Calyx 3-5 mm, with several black discoid gland patches;teeth 5, sharply triangular. Corolla yellow, 3-4 cm, 2-lipped, sparsely glandular;lower lip 3-lobed, outside yellowish brown puberulent, inside glabrous;upper lip entire or slightly 2-cleft. Ovary glabrous, glandular. Stigma unequally 2-cleft. Drupes yellow when ripe and black when dry, ellipsoid to obovoid-ellipsoid, 1.5-2 cm (Flora of China Editorial Committee, 2016).
B. orientalis is a semi-rosette biennial or perennial hemicryptophyte, 25(40) to 100(150) cm tall. The stems are sparsely pilose with simple, stalked, forked trichomes. The stem is covered with multicellular glandular tubercles present throughout except for the flowers, and these can be seen with the naked eye. The stems are usually branched above or rarely basally. The diameter of the leaf rosette reaches up to 100 cm. The lower leaves are up to 15 (20) cm long, lanceolate or with three-cornered edges or sharp-edged;the upper leaves are entire to pinnatifid and always smaller than the lower leaves. The petals are 4-8 mm long, yellow, entire or truncate. The fruit is asymmetrically ovoid and covered with small, irregular protuberances with one or two subglobose, plump, 2.0-2.5 mm diameter seeds per fruit. A detailed description is available from Flora of China (2009).
Tree up to 20 m, usually glabrous. Leaves large, several-foliolate, petiole about 5 cm. long, eglandular, rachis usually 2-4 dm. long, like the petiole, stipules small, caducous, leaflets normally 4-8 pairs, 8-20? 8 cm, ovate to lanceolate, acute apically, very obtuse basally, puberulent to glabrous above, lightly pubescent below, petiolules up to 1 cm. long. Inflorescence a large, graceful, pendent, many-flowered raceme, pedicels slender, usually 3-4 cm. long. Flowers large, showy, yellow, sepals 5, (usually about 6 mm. long), ovate or oblong, puberulent, petals 5, about 2 cm. long or longer, ovate-orbicular, short-clawed, venose, stamens 3-morphic, the 3 lowermost almost 3 cm. long, the anthers ovate-oblong, 4-5 mm. long, glabrous, dehiscent apically and basally, the 4 median stamens about 1 cm. long, the anther ovate-oblong, sagittate, about 4 mm. long, dehiscent from the basal lobes (and apical pores), 3 uppermost stamens shorter and smaller, somewhat unequal, the anthers similar to the median ones, ovary slender, lightly pubescent. Legume reportedly cylindric, about 50 cm. long, indehiscent, with horizontal seeds [Flora of Panama, 2014].
The following description is taken from the Flora of North America Editorial Committee (2016);Perennials, 17Ð100(Ð140) cm, loosely to densely colonial or some??times cespitose, long-rhi?zomatous. Stems 1Ð5+, erect (straight, stout to slender, often reddish), glabrous and hairy in lines distally or sometimes wholly strigoso-pilose (var. villicaule). Leaves thick, firm, ± fleshy, margins scabrous, apices mucronate, faces glabrous, abaxial midveins sometimes villosulous (var. villicaule), basal withering by flowering, petiolate (petioles winged, bases sheathing), blades ovate to ovate-lanceolate or lanceolate, 17Ð60+ ? 6Ð11+ mm, bases attenuate to cuneate, apices obtuse, proximal cauline withering by flowering, sessile or widely winged-petiolate (petioles clasping), blades lance-ovate or -obovate to elliptic to linear-lanceolate, 40Ð200 ? 4Ð40 mm, bases cuneate or sometimes slightly attenuate, sometimes rounded or slightly auriculate, slightly clasping, apices acute to acuminate, distal sessile, blades lance-ovate to linear-lanceolate, 13Ð62 ? 3Ð15 mm, progressively reduced distally, bases cuneate or ± rounded, sometimes slightly auriculate, ± clasping, margins sparsely serrulate or entire. Heads in open to dense, paniculiform arrays, branches ± divaricate to ascending, leafy with remote, small, gradually reduced branch leaves. Peduncles 4Ð41 mm, glabrous or moderately pilose, bracts 1Ð3, lanceolate or ovate to linear-oblanceolate, subtending ones sometimes exceeding involucres, sometimes grading into phyllaries. Involucres campanulate, 6Ð9 mm. Phyllaries in 3Ð4 series, oblong-oblanceolate or -spatulate (outer) or oblong-lanceolate to linear-lanceolate or linear (inner), ± unequal to subequal, bases indurate 1 / 5 Ð 1 / 3, margins hyaline, scarious, erose and sparsely ciliolate distally, green zones lanceolate, sometimes foliaceous, apices spreading to ± squarrose, usually acute to obtuse or ± long-acuminate, mucronulate, faces glabrous. Ray florets 15Ð35, corollas usually blue-violet or purple, rarely pink or white, laminae (6Ð)10Ð19 ? 0.9Ð2.1 mm. Disc florets 28Ð68, corollas yellow becoming reddish brown to purple, 4Ð7.5 mm, tubes shorter than funnelform-campanulate throats, lobes lanceolate, 1Ð1.5 mm. Cypselae tan to brown, obovoid, compressed, 2Ð4 mm, 4Ð6-nerved, faces sparsely strigose to glabrate, pappi sordid to yellowish, 4Ð6 mm.
Deciduous, densely tufted bamboo, culms 7Ð17 m, (3Ð)6Ð10 cm in diameter, internodes 30Ð45 cm, white powdery, wall thick, culm often solid. Branches several, main mid-culm ones 3. Culm sheaths deciduous, orange-brown, approximately 3/4 as long as internodes, thickly papery, margins ciliate, apex rounded, auricles absent, ligule 1Ð3 mm, serrulate, blade erect, narrowly triangular. Leaf sheaths initially sparsely hairy, becoming glabrous, ligule short, serrulate, blade usually narrowly lanceolate, 5Ð30 ? 1Ð3 cm. Pseudospikelet clusters 2.5Ð5 cm in diameter. Spikelets 8Ð15 mm, usually densely pubescent, fertile florets 2Ð4. Glumes 2 or more, 6Ð8 mm, long mucronate, lemma 9Ð10 mm, apex long mucronate, palea 8Ð9 mm. Anthers yellow, approximately 5 mm, connective apically produced. Caryopsis brown, shining, ovoid to sub-globose, about 8 mm long, hairy above, beaked with the persistent base of the style, pericarp coriaceous (Flora of China Editorial Committee, 2015, Flora of Pakistan, 2015).
J. curcas is a shrub or treelet, 2-5 m tall, with watery latex;bark smooth;branches glaucous-gray, glabrous, sparsely lenticellate, pith larger. Stipules small;petioles 6-18 cm;leaf blade rotund to ovate, 7-18 ? 6-16 cm, papery, nitid green and glabrous adaxially, gray-green and along nerves puberulent to glabrous abaxially, base cordate, apex acute;palmate veins 5-7. Inflorescences axillary, 6-10 cm;bracts lanceolate, 4-8 mm. Male flowers: sepals 5, approximately 4 mm, connate at base;petals oblong, green-yellow, approximately 6 mm, connate to middle, hairy inside;disk glands 5, nearly terete;stamens 10;outer 5 filaments free, inner filaments connate in lower part. Female flowers: pedicels elongate;sepals free, approximately 6 mm;petals and disk glands as in male;ovary 3-locular, glabrous;styles bifid at apex. Capsules ellipsoidal or globose, 2.5-3 cm, yellow. Seeds ellipsoidal, 1.5-2 cm, black (Flora of China Editorial Committee, 2015).
Description from Flora of China Editorial Committee (2014): V. fordii is a deciduous tree, up to 10 m tall, monoecious, bark gray, nearly smooth, branches verticillate, stout, glabrous, prominently lenticellate. Petiole as long as leaf blade, glabrescent, with 2 compressed and sessile glands, leaf blade ovate, 5-18 ? 3-15 cm, puberulent when young, dark green and glabrous adaxially, gray-green and pubescent abaxially at maturity, base truncate to shallowly cordate, margin entire, rarely shallowly 1-3-fid, apex acute, palmate veins 5(-7). Inflorescences flat-topped paniculate cymes, appearing generally before new leaves, usually bisexual, calyx ca. 10 mm, 2(or 3)-fid, densely brown puberulent outside, petals obovate, 2-3 ? 1-1.5 cm, yellow at base, pink to purplish, pink-veined, base clawed, apex rounded, stamens 8-12, outer filaments free, inner filaments connate to below middle, ovary 3-5(-8)-locular, pubescent, styles 3-5(-8), bifid. Drupe subglobose, 4-6(-8) cm in diam., exocarp smooth, not grooved, 3- or 4(-8)-seeded. Seed coat woody.
E. japonicus grows as an evergreen shrub or small tree that can reach up to 3 m, sometimes dwarfed. Branches are grey-green to grey-brown, terete glabrous and sturdy. Twigs are green to light green, glabrous, and not evidently striate, especially when fresh. The petiole is 3-10 mm long. Leaf blades are leathery or thickly leathery, ovate, obovate, orbicular-ovate or long ovate, measuring (3-)5-10(-12) x (2-)3-5(-5.5) cm, base orbicular or semiorbicular, margin crenulate distally, nearly entire proximally, apex orbicular or semiorbicular;lateral veins 6-8 pairs, slightly visible or unclear, especially when dry. Leaves are often variegated in cultivated varieties. Cymes usually axillary, sometimes terminal, many branched with many flowers;peduncle up to 8 cm, sub-branches 2-4 cm;pedicel 4-7 mm. Flowers are 4-merous, 5-6 mm in diameter;sepals nearly orbicular;petals greenish white or yellowish green, sometimes cream, nearly orbicular. Capsule globose or subglobose, brown or yellow-brown to red-brown, 6-9(-12) mm in diameter, 4-lobed. Seeds 2 per locule, 5 x 3.5 mm, dark brown, globose;aril orange-red (Flora of China Editorial Committee, 2017).
Stems to 15 m tall, 20-30 cm in diameter, rough with leaf scars. Leaves are palmate;petioles to 1.8 m, with green or black recurved spines along margins, spines denser proximally, fewer distally on petioles;hastula to 3 cm;blades almost circular in outline, 1.2-1.8 m wide, green on both surfaces, regularly divided to c. half their length into 50-90 segments, these split and pendulous at apices. Inflorescences are 1-1.2 m, branched to three orders, with six or seven partial inflorescences;rachillae 10-18 cm;flowers hermaphroditic, borne in clusters of 4-7, white or yellow, 2-2.5 mm. Fruits are green or blue-green, globose to ellipsoid or pear-shaped, 1.5-2.6 x 0.9-1.8 cm (Flora of China Editorial Committee, 2016).
L. chinensis negatively impacts Acanthophoenix rubra, a critically endangered palm endemic to Mauritius (Maunder et al., 2001).
The following description is taken from Flora of China Editorial Committee (2015);Plants 3-12(-15) m tall, densely branched, young parts finely pubescent or glabrous. Leaves 7-25 cm, petiole 2-8 cm, leaflets (3-)5-13, petiolules 1-2.5 mm, leaflet blades ovate to elliptic, 3-8 ? 1.5-4.5 cm, abaxially pubescent to nearly glabrous, base obliquely rounded, apex acute to acuminate. Inflorescences axillary or rameal, panicles or cymes, branches and flower buds crimson. Flowers numerous, small. Sepals narrowly elliptic, 3-5 mm, base sparingly pubescent. Petals white with purple markings or pink to red with darker markings, 6-9 ? 3-4 mm. Shorter stamens sterile, occasionally 1 or 2 fertile. Ovary pubescent. Berry yellow to yellow-brown, oblong, 7-13 ? 5-8 cm, deeply (3-)5(or 6)-ribbed, stellate in cross section, very fleshy. Seeds numerous, blackish brown.
Trees to 20 m tall;trunk to 2 m dbh. Bark brownish black, longitudinally peeling. Branches spreading, forming tiers. Branchlets densely brownish yellow tomentose near apex, densely covered with conspicuous leaf scars. Leaves alternate, crowded into pseudo-whorls at apices of branchlets;petiole 0.5Ð2 cm, stout, tomentose;leaf blade obovate to oblanceolate, narrowed in proximal half, 12Ð30 ? 8Ð15 cm, both surfaces glabrous or abaxially sparsely softly hairy when young, base narrow, cordate or truncate, apex obtuse or mucronate;lateral veins in 10Ð12 pairs. Inflorescences axillary, simple, long, slender spikes, 15Ð20 cm, numerous flowered;axis shortly white tomentose. Flowers fragrant. Calyx tube distally cupular, 7Ð8 mm, abaxially white tomentose, densely so on ovary, sparsely so on cupular part, adaxially glabrous;lobes 5. Stamens 10, exserted, 2Ð3 mm. Fruit not stipitate, red or blackish green when ripe, ellipsoid, slightly to strongly compressed, strongly 2-ridged to narrowly 2-winged (wings to 3 mm wide), 3Ð5.5 ? 2Ð3.5 cm, glabrous;pericarp woody, rigid (Flora of China Editorial Committee, 2017).
Shrub or suffrutescent herb to 1.5 m tall, stem striate, strigulose. Leaves trifoliolate, the terminal leaflets narrowly elliptic to elliptic, the apex acute, acuminate or mucronulate, the base cuneate, 4.5-5.5 cm long, 1.1-1.5 cm broad, the margins entire, above glabrous, beneath sparsely strigulose, the veins 8-10 on each side of the mid-vein, the lateral leaflets similar, but slightly smaller;petiole 3-4 cm long, the stipules absent. Inflorescences terminal, lax racemes bearing up to 20 flowers;bracts linear triangular, 1-2 mm long, caducous;pedicels 5-6 mm long;bracteoles linear, 1 mm long, strigulose, located at the base of the calyx tube, caducous. Flowers yellow, 15-18 mm long;calyx 8-9 mm long, the tube truncate, the lobes about 1.5 times as long as the tube, strigulose;corolla yellow or tinged with violet, 15-18 mm long, the standard 13-14.5 mm long, 14.0-15.5 mm broad, retuse, the wings 13-14 mm long, the claws 2-3 mm long, oblong obovate, oblique, the keel 14-15 mm long, the non-twisted beak prolonged;stamens dimorphic, the long anthers 3.3-3.5 mm long, the short anthers 0.7-0.8 mm long;style with a pubescent stigma, curved geniculate, 9.5-12.0 mm long. Legume inflated, 2.5-3.1 cm long, strigulose;seeds approximately 20, brown, oblique, 3 mm long (Flora of Panama, 2015).
C. maypurensis is a shrub or herb listed as invasive in Cuba by Oviedo Prieto et al. (2012), although other databases regard it as native on this island (Acevedo-Rodríguez and Strong, 2012;USDA-ARS, 2015). Within its native distribution range in tropical America, this species is associated with disturbed vegetation and grows in open ground, secondary forests and riparian sites (Gómez-Sosa, 2000;Avendaño, 2011).
Leafy shrubs or small trees 1-5 (-6.5) m tall. Leaflets 3-4 (5) pairs, the distal ones larger, broadly ovate to lanceolate, (3.5-) 4.5-10.5 cm long, (1.1-) 1.4-3.5 cm wide, glabrous, lower surface pale, apex acuminate or caudate, base obliquely rounded or cuneate, petiolar nectaries between all pairs or all but the distal pair of leaflets, none contiguous to pulvinus, the lowest one 1-2 mm long, stipules submembranous, narrowly lanceolate, 3-7 mm long, caducous. Flowers in racemes (1.5-) 2.5-8 cm long, pedicels (12-) 15-25 mm long, bracts sub-membranous, linear, lanceolate, or subulate, (1.5-) 2-4.5 mm long, caducous as pedicels begin to elongate;calyx lobes yellowish green, yellowish brown, or completely yellow, the outer ones relatively firm, ovate-elliptic, 4-6.5 mm long, the inner ones submembranous, oblong-obovate or suborbicular, 6.5-10 mm long;petals bright yellow, the standard obovate to obovate-flabellate, deeply emarginate, the others obovate, the longest petal 12-16 mm long;staminodes 3, obovate or suborbicular, (1.7-) 2-2.6 mm long;filaments of 4 median stamens 1.3-2.2 mm long, those of 2 abaxial stamens dilated, ribbon-like, 7-10.5 mm long, that of abaxial central stamen 2-4 mm long. Pods ascending on a stiff pedicel, chartaceous, cylindrical or obtusely quadrangular, 6-10.5 cm long, 0.8-1.1 cm wide, cavity moderately pulpy, divided into 2 parallel rows of of cells. Seeds oriented with broad face to the septum, olive or brown, compressed-obovoid, 3.6-4.9 mm long, constricted at the hilum, smooth or minutely pitted, without an areole (Wagner et al., 2014).
S. septemtrionalis is a leafy shrub or small tree which abundantly produces seeds that are easily dispersed by humans (machinery and vehicles), birds and animals, and by water (West, 2003). Once established in new areas, this species matures quickly, negatively impacting native flora. The species is listed in the Global Compendium of Weeds as an “agricultural weed, cultivation escape, environmental weed, garden thug, naturalized, weed” with records of occurrences in North and Central America, South America, Asia, Asia-Pacific, Africa, Australia, and Europe (Randall, 2012;DAISIE, 2014;USDA-ARS, 2014). It is considered invasive in Fiji, Australia, Ecuador, Hawaii, New Zealand, and a weed in South Africa and the United States (see Distribution Table;Randall, 2012;PIER, 2014). It is also recorded as invasive in Burundi, Ethiopia, Kenya, Malawi, Rwanda, Tanzania and Uganda. The species was given an Australian rating of 4, indicating it is “naturalised and known to be a major problem at 3 or fewer locations within a State or Territory” (Groves et al., 2003);according to the Global Compendium of Weeds, the species is indeed invasive in some parts of the country (Randall, 2012).
Tree to 10 or more metres high, the branchlets usually tomentose when young. Leaves moderately large, an average leaf about 20-foliolate;petiole short, pubescent, eglandular;rachis usually about 2 dm. long, eglandular and otherwise like the petiole;leaflets several to many pairs, lanceolate, 3-8 cm. long and usually about 2 cm. wide, acute apically, obtuse basally, pubescent below, especially along the veins, puberulent to subglabrous above and less dull than below, opposite on the rachis, with 10 or more pairs of prominent lateral veins;petiolules 2-3 mm. long, pubescent. Inflorescence of several terminal or subterminal several-flowered racemes;bracts lanceolate, a few mm. long, caducous. Flowers yellow;sepals 5, obovate-orbicular, markedly unequal, up to 1 cm. long and broad, glabrous to lightly puberulent;petals 5, mostly obovate, markedly unequal, up to 2.5 cm. long and 1.5 cm. broad, subglabrous, venose, short-clawed;stamens 10, 3-morphic;the 3 lowermost the largest, their anthers oblong, about 7 mm. long, short-rostrate apically and dehiscent by terminal pores, the loculi somewhat converging terminally;anthers of 4 median stamens 5-6 mm. long, similar to the 3 lowermost except the rostrum reflexed and the loculi divergent terminally;3 uppermost stamens markedly dissimilar, more or less rudimentary, the anthers distinctly bilobed, each lobe reniform and dehiscent the length of its outer margin;ovary linear, glabrous. Legume linear, turgid-quadrangular, up to 2 dm. long and 1 cm. wide, transversely multiseptate, tardily dehiscent along one margin (Missouri Botanical Garden, 2014).
S. spectabilis is a medium to large tree from tropical America, listed in the Global Compendium of Weeds as an ‘environmental weed’, ‘garden thug’, and ‘naturalised weed’ (Randall, 2012). The species is extremely fast-growing, flowers and sets seed profusely, and re-sprouts readily when cut (Mungatana and Ahimbisibwe, 2010). In Australia it is considered naturalized, has been recorded as a weed of the natural environment and an escape from cultivation, and is labelled an invasive species, indicating its high negative impact on the environment due to its ability to spread rapidly and often create monocultures (Randall, 2007). In Uganda, the species is considered an invasive alien species with high risk to the native flora (Mungatana and Ahimbisibwe, 2010). In Singapore S. spectabilis has been identified as a casual, spontaneous exotic species that survives outside cultivation but does not form self-replacing populations, and relies on repeated introductions or limited asexual reproduction for persistence (Chong et al., 2009). The species is a cultivation escape in Trinidad and Tobago (Irwin and Barneby, 1982) and is considered an invasive species in Cuba (Oviedo-Prieto et al., 2012).
Agroforestry experiments in Kenya showed that while S. spectabilis is useful as hedges for cropping systems, if grown in semi-arid conditions S. spectabilis will out-compete crops for water uptake and suppress crop yields;in the cases recorded, grain yields of maize grown with S. spectabilis or Leucaena leucocephala were reduced by between 39% and 95% (Noordwijk et al., 2004).
The following description is from Flora of China Editorial Committee (2015)
A. indicum is a common weed, found in open, sunny and warm areas, from sea level to ca. 1600 m altitude. It is listed as an invasive mostly in Asia and Oceania (PIER, 2015;PROTA, 2015). It is not considered a threat at high elevations (PIER, 2015). The species is used widely in its native range as a traditional medicinal plant (Mohite et al, 2012;Vadnere Gautam et al., 2013), and was probably introduced for cultivation outside its native range for medicinal purposes. For some of the countries where it is reported as invasive, it is also listed as cultivated, making it probable that the species escaped from cultivation into suitable habitats, as it is listed as found in disturbed areas near dwellings and roadsides (PIER, 2015). No published details are available about the extent of invasiveness or the impacts of the species in the regions where it is reported as invasive.
Leaf residue extracts of A. indicum have been evaluated for their effect on the germination and growth of the wheat cultivars, Sind-81, Sind-83 and Sarsabz, and chickpea cv. CM-72. The extracts did not inhibit germination, but stimulated the shoot length of all the cultivars. Root inhibition was found for all, except Sind-81 and chickpea (Alam and Azmi, 1990).
The following information is provided by the Flora of Australia (2015)
A. longifolia is a shrub or small tree native to Australia that has been deliberately introduced in various countries, mainly for dune stabilization and soil improvement (Dennill and Donnelly, 1991;Marchante et al., 2008;Stellatelli et al., 2014). It is recognized as an aggressive invasive weed in parts of its native range in Australia, and in some of the countries where it has been introduced;such as in South Africa, Spain and Portugal. Although is reported by PIER (2015) as invasive in California, USA, and was stated by Whibley and Symon (1992) as having established naturalized populations, it is reported as uncommon by Baldwin et al. (2012) and it is not listed in the California Invasive Plant Inventory (California Invasive Plant Council, 2016). It has a prolific seed production, and fast growth, facilitating its spread in suitable habitats (Rodríguez-Echevarria, 2010;Marchante et al., 2011). A. longifolia is associated with invasion events in New Zealand (Haysom and Murphy, 2003), and is recorded as invasive in Brazil (Instituto Horus, 2011).
A. longifolia affects the biodiversity and ecosystems by altering the microbial communities and by its high resource utilization, outcompeting native species (Marchante et al., 2008;Werner et al., 2010). It is included in the IUCN Global Invasive Species Database (GISD, 2015) and is reported as being costly to eradicate (EFSA Panel on Plant Health, 2015).
The following description is from Flora Zambesiaca (2016): Erect or ascending, bushy perennial herb (commonly cultivated as an annual), c. 5–45 cm tall, stem and branches villous when young but soon glabrescent, older parts terete, younger bluntly quadrangular. Leaves narrowly or more broadly elliptical to oblanceolate or rhomboid-ovate, acute to acuminate at the apex, attenuate into a slender, indistinctly demarcated petiole below, thinly furnished with fine, whitish hairs to subglabrous, often reddish or purple suffused and not rarely variegated. Heads axillary, sessile, usually solitary, globose to ovoid, 4–6 mm in diam.;bracts pale, deltoid-ovate, c. 2 mm long, glabrous, lacerate-margined, aristate with the excurrent midrib;bracteoles similar but slightly shorter. Tepals white, lanceolate to oblong-elliptic, 3.5–4 mm long, acute, mucronate with the excurrent midrib;outer 2 prominently 3-nerved below and darker in the nerved area, with a line of whitish, minutely barbellate hairs on each side of this area, the hairs becoming denser towards the base of the tepal;inner 2 slightly shorter, narrower and less rigid, mostly 1–2-nerved;central tepal intermediate. Stamens 5, at anthesis much exceeding the ovary and style, the alternating pseudostaminodes subequalling the filaments plus anthers, narrowly oblong, laciniate at the apex. Ovary strongly compressed, obpyriform, 0.6 mm long, style about the same length. Ripe fruits and seeds usually not seen.
There are no published reports about the invasiveness of A. bettzickiana, a cultivated herb not known from the wild other than where escaped from cultivation. In most of the countries where it occurs, it is reported as an ornamental species (Missouri Botanical Garden, 2016). In Palau, although is listed as only planted near the Capitol, it is listed as a species of possible threat without further information (Space et al., 2009). In Texas it is not considered as a threat to native plant communities, although occasionally escaping to disturbed areas near where planted (Nesom, 2009). It is reported as a short-term escape for India (Sankaran et al., 2014) and common and not invasive in Taiwan (Wu et al., 2004). It is also escaped and naturalized in the British Virgin Islands, Costa Rica, Colombia, Dominican Republic, Peru and St. Lucia (D’ Arcy, 1967;Graveson, 2012;Missouri Botanical Garden, 2016), but without further details.
Procumbent or decumbent sericeous perennials, the sparingly branched stems to 20 cm long. Leaves densely pubescent with stellate hairs, rarely glabrate, elliptic to ovate, apically rounded and mucronate, basally rounded to cuneate, 1-5 cm long, 0.5-2.5 cm broad;petioles 2-10 mm long. Inflorescences of stramineous ovoid heads, 4-12 mm long, 3-5 mm broad, sessile in the axils. Flowers perfect;bracts and bracteoles subequal, ovate, acuminate to aristate, 1-3 mm long;sepals 5, the outer 3 broader, 3-ribbed, basally indurate and hispidulous, 3-5 mm long;stamens 5, united below into a tube, the pseudo-staminodia lacerate and exceeding the filaments;ovary globose to obovoid;style 1, about twice as long as the capitate stigma. Fruit an indehiscent globose utricle 1-1.5 mm long;seeds reddish brown, cochleate-orbicular, 0.8-1.1 mm broad (Correa et al., 2004).
Alternanthera halimifolia is a pioneer species typically growing in disturbed and coastal areas. Its native range encompasses the majority of the Caribbean in addition to Central and South America. This species has been listed as introduced and invasive in Cuba, although some authors regard it as native to this island. It has also been listed as introduced in Puerto Rico and the United States Virgin Islands (St Croix and St Thomas). In Chile it has been previously listed as introduced but most recently included within a list of native flora. It behaves as a weed in ruderal sites, sea beaches, coastal sites, and thickets in areas both within and outside its native distribution range.
The following description has been modified from the Flora of North America (2014). Annual, (10–)20–60(–180) cm high. Leaves: petioles 10–40(–60) mm long;blades deltate to lance-ovate overall, 30–80(–150+) × 20–60(–100+) mm long, 3(–5)-foliolate, leaflets petiolulate, lanceolate to lance-ovate, (15–)35–60(–120) long × (5–)10–20(–30) mm across, bases cuneate, margins dentate to serrate, sometimes ciliate, apices acuminate to attenuate, faces glabrous or hirtellous. Heads usually borne singly, sometimes in 2s or 3s or in open, corymbiform arrays. Peduncles 10–40(–80+) mm long. Calyculi (subsidiary circle of small bracts outside the involucral phyllaries) of (5–)8(–10) ascending to spreading, spatulate or oblanceolate to linear, sometimes ± foliaceous bractlets or bracts 5–20(–60) mm, margins usually ciliate, abaxial faces glabrous or hirtellous. Involucres campanulate to hemispheric or broader, 6–9 × 7–12 mm. Phyllaries (bracts surrounding the capitulum) 6–12, oblong or ovate to lance-ovate, 5–9 mm. Ray florets 0 or 1–3+;laminae golden yellow, 2–3.5 mm. Disc florets 20–60(–120+) mm long;corollas ± orange, 2.5–3+ mm. Cypselae (fruits) blackish to brown or stramineous, ± obcompressed, obovate to cuneate, outer 5–7 mm, inner 7–10 mm, margins antrorsely or retrorsely barbed, apices ± truncate to concave, faces usually 1-nerved, sometimes tuberculate, glabrous or sparsely hirtellous;pappi of 2 ± erect to spreading, antrorsely or retrorsely barbed awns 2–5 mm.
B. frondosa is a herbaceous annual native to North America. It has been introduced widely in Europe and to other parts of the world and is mostly found in temperate climates. The majority of introductions into new countries are intentional, due to the medicinal, herbal and decorative properties ascribed to the species. However, seeds can be accidentally dispersed into new areas as they can adhere firmly to animal fibres such as wool. In Europe B. frondosa has been reported to outcompete and interbreed with native plant species in particular those of the same genus. B. frondosa is classified as an environmental weed in New Zealand.
C. capitatum is an annual or short-lived perennial (Sukhorukov et al., 2018). The following description is based on the one given in the Flora of North America (e Floras, 2008). Herbaceous, glabrous stems, 150–100 cm long, erect to ascending or decumbent, branching from the base. Leaves: blades lanceolate, ovate, triangular or triangular-hastate, 2.5–10 x 1–9 cm, base cuneate, truncate, or hastate, margins sharply dentate or entire, apex acute to acuminate;petiole 1.5–10 cm. Inflorescences: glomerules (dense clusters of small sessile flowers) borne on unbranched terminal spikes;spikes 5–20 cm;glomerules globose, 3–10 mm diameter;bracts leaf-like, present only at base of inflorescence;flowers maturing from apex to base. Flowers: perianth segments three, joined only at base, lobes lanceolate to ovate, 0.6–0.9 x 0.4–0.5 mm, apex acute, not keeled, glabrous, covering fruit at maturity, becoming fleshy and red in fruit;stamens three;stigmas 2, 0.1–0.4 mm. Achenes ovoid, may or may not be fleshy;pericarp adherent, bright red to dark reddish brown or greenish red, smooth. Seeds 0.7–1.2 mm in diameter, margins rounded;seed coat black, reticulate-punctate.
Chenopodium capitatum is a chenopod herbaceous plant found across parts of North America (where it is native), and also in Europe and New Zealand. It is sometimes cultivated as a horticultural crop;it has the potential to become an invasive species in some areas.
C. terniflora is a climbing, semi-evergreen, woody vine (Swearingen and Bargeron, 2016). Stems are 3-6 m, climbing with tendril-like petioles and leaf rachises (Flora of North America Editorial Committee, 2018). Leaves are shiny, green and leathery (Missouri Botanical Garden, 2018), and are opposite, compound, with 3-5 leaflets of 5-7.5 cm and margins entire (Swearingen and Bargeron, 2016). Leaflets are ovate or broadly lanceolate to narrowly deltate (Flora of North America Editorial Committee, 2018). Inflorescences are axillary 3-12-flowered cymes (or compound cymes or paniculate with cymose subunits) (Flora of North America Editorial Committee, 2018). Flowers are 1.4-3.0 cm in diameter (Flora of China Editorial Committee, 2018), bisexual often with some unisexual flowers in the same inflorescence, with pedicels of 1-3.5 cm (Flora of North America Editorial Committee, 2018). Flowers are fragrant with four slender white petal-like sepals (Swearingen and Bargeron, 2016) that are obovate-oblong and measure 5-15 x 2-6 mm (Flora of China Editorial Committee, 2018). Flowers have up to 50 stamens and 5-10 unicarpellate pistils (Flora of North America Editorial Committee, 2018). The ovary is superior (Burnham, 2013). Seeds are enclosed in flattened achenes, production is prolific, and seed heads have long, silvery-grey, feather-like hairs (Swearingen and Bargeron, 2016). Each achene has a plume attached (Mahr, 2017), and this helps with wind dispersal (Burnham, 2013). The mature bark is light brown and shreds longitudinally (Burnham, 2013).
Clematis terniflora is a perennial woody vine, native to Asia and introduced to North America as an ornamental. It can self-seed, and has escaped cultivation and naturalized in many parts of the USA. It is reported to be invasive in a number of eastern states. It grows in forest margins, scrub, grassy areas on hills and slopes, and in disturbed areas such as roadsides, thickets and urban green spaces. Seeds are widely dispersed by wind. It grows rapidly, forming dense clumps that outcompete and cover young native trees, shrubs and herbs at ground level and suppress seed germination. It can also climb to nearly 10 m, smothering trees and pulling down telephone poles. C. terniflora is difficult to control. Removal by hand can help encourage the growth of native species, but is unlikely to eliminate C. terniflora entirely due to root re-sprouting and prolific seed production. Some herbicides have proven effective in controlling the spread of this species;however, repeated applications are necessary.
Short, evergreen shrubs growing 20 – 70 cm tall. Leaves opposite, narrowly lanceolate, 10-35 × 1-8 mm. Solitary flowers grow from the leaf axils along the branches. Each flower has 6 pink, purple or white petals (3-3.5 mm long) emerging from a green floral tube (5-8 mm long). The calyx teeth are triangular and the calyx may be glabrous or with a few stiff hairs. Fruits are 3-lobed capsules containing 5-8 seeds, each about 1 mm in diameter (Flora Mesoamericana, 2016).
Considered a transformative invasive plant in Cuba by Oviedo Prieto et al. (2012);however, no information could be found on this species’ environmental impacts. It is considered a potentially serious weed in Hawaii (HEAR, 2016). Naturalized in tropical regions around the world where it has been widely planted as an ornamental (HEAR, 2016).
E. atrovirens is a caespitose perennial grass. Rhizomes absent. Culms loosely tufted, erect or geniculate at base, 15–100 cm tall, approximately 4 mm in diameter, 4–8-noded. Leaf sheaths glabrous but pilose along summit;ligules a ciliolate membrane, 0.2–0.3 mm;leaf blades flat or involute, 4–17 × 0.2–0.4 cm, adaxial surface scabrous, near base pilose, abaxial surface glabrous. Panicle open, 5–20(–25) × 2–15 cm;branches one to several per node. Spikelets plumbeous and purplish, narrowly oblong, 5–15(–25) × 1.5–2.5 mm, 8–40-flowered, pedicels 0.5–5(–15) mm;rachilla persistent. Glumes 1-veined, 1–2.3 mm;lower glume ovate, 1–1.3 mm, apex acute, upper glume narrowly ovate, 1.3–2.3 mm, apex acuminate. Lemmas broad ovate, 1.8–2.2 mm, apex acute, lower lemma 2–2.2 mm, deciduous with palea. Palea loosely ciliate along keel, 1.6–1.8 mm. Stamens 3;anthers 0.7–0.9 mm. Caryopsis approximately 1 mm (Barkworth et al., 2004;Flora of China Editorial Committee, 2016).
Eragrostis atrovirens is a C 4 grass cultivated for pasture and hay in tropical and subtropical regions (USDA-ARS, 2016). It has escaped from cultivation and once naturalized it behaves as a weed in roadsides, disturbed sites, waste areas, riparian areas, and grasslands (Barkworth et al., 2004;Flora of China Editorial Committee, 2016;PIER, 2016;PROTA, 2016). This perennial grass has the capability to tolerate drought and high saline conditions as well as seasonally waterlogged conditions. Thus, it can be found growing in floodplain grassland and swampy grassland (Flora of Pakistan, 2016). Currently, it is listed as invasive in Australia, Micronesia, Palau, Chagos Islands, Cuba, and Mexico (Villaseñor and Espinosa-Garcia, 2004;Oviedo Prieto et al., 2012;Simon and Alonso, 2016;PIER, 2016).
Trees or shrubs, producing abundant milky latex when injured, 2-6 m tall, dioecious, eventually forming a trunk 10-25 cm DBH with rugose, gray or light bark. Stems green, succulent, finely, longitudinally striate. Leaves alternate, present only on new growth;stipules very small, caducous;petiole ± absent;leaf blade oblong-linear, 7-15 × 0.7-1.5 mm, base attenuate, margin entire, apex obtuse. Cyathia clustered at apex of branches, pedunculate, unisexual;involucral leaves minute, membranous, caducous;involucre turbinate, approximately 2 × 1.5 mm, shortly pubescent inside;glands 5, peltate-ovate or subrounded. Male flowers many, exserted from involucre. Female flower: ovary glabrous, exserted from involucre;styles connate below middle;stigma 2-lobed. Capsule 3-lobed, 8 × 8 mm, smooth, sparsely pilose or glabrous. Seeds ovoid-globose, 4 × 4 mm, smooth;caruncle small (Flora of China Editorial Committee, 2016).
E. tirucalli is a many-branched succulent plant widely commercialized as an ornamental, hedge plant, potted plant and for soil conservation (Orwa et al., 2009;USDA-ARS, 2016). It has escaped from cultivation and once naturalized, it often grows forming thickets mostly in disturbed sites, abandoned gardens, deciduous forests, semiarid sites, and along roadsides (Little et al., 1974;PIER, 2016). This species grows very fast, and produces a lot of biomass even under very marginal soil and extreme climatic conditions (Mwine and Damme, 2011). In invaded areas, it is propagating vegetatively by cuttings and stem fragments (Little et al., 1974;PIER, 2016). Currently, this species is listed as invasive in Hawaii and Cuba (Oviedo Prieto et al., 2012;PIER, 2016), but is listed as potentially invasive on many islands in the Pacific and in tropical and subtropical areas of Asia (Nguyen and Sosef, 1999;Flora of China Editorial Committee, 2016;PIER, 2016).
The following description is from the Flora of China Editorial Committee (2016)
Euphorbia tithymaloides is a succulent, perennial shrub widely cultivated as an ornamental plant. Native to the Americas, this species has been introduced in Africa, Asia and Oceania, occurring on rocky soils in dry, sunny habitats such as hillsides, wastelands and roadsides. Currently it is listed as invasive in New Caledonia, Wake Island, the British Indian Ocean Territory and Cuba. Despite being classified as high risk in the Hawaii-Pacific Weed Risk Assessment, its environmental impact on native species and habitats is unknown.
The following description from is from Flora of China Editorial Committee (2016)
L. virginicum is an annual herb that has been reported as capable of causing ecological or economic damage in the Pacific Islands, the Western USA and as spreading in Grand Cayman in the Cayman Islands (GISD, 2016). It is a noxious weed causing economic losses in cultivated fields due to reduced crop yields (Romm, 1938;Jones Jr. and Davis, 1963;Coelho et al., 2009), and is a weed of turf in the USA. It is invasive in Cocos Island, China, Philippines, Hawaii (USA), Cuba, Ecuador, French Polynesia, Guam, New Caledonia, New Zealand, Niue, Palau and Tonga (Kim and Ewing, 2006;Oviedo Prieto et al., 2012;PIER, 2016). It is specifically listed as an invasive species of the sand dunes in South Korea (Kim and Ewing, 2006). In China it is a Group II Species, referring to species that occupy a large area and/or have a strong negative influence over the habitat (Liu et al., 2006). In Cuba it is invasive in citrus orchards, being one of the most problematic weeds (Otero-Pujol et al., 2015). A Weed Risk Assessment adapted for Hawaii gave the species a High Risk score of 17 (PIER, 2016).
L. microphyllum is a climbing fern, with long-creeping stems. Leaves to ca. 10-15 mm on petioles borne 2-5 mm apart, 7-25 cm long, with sterile and fertile pinnae. Sterile pinnae on 0.5-1.5 cm stalks, oblong, 1-pinnate, 5-12 × 3-6 cm;ultimate segments triangular-lanceolate to oblong-lanceolate, truncate to shallowly cordate or somewhat auriculate proximally, usually not lobed, but if lobed, lobes rounded at apex and not directed toward leaf apex;segment apex rounded-acute to obtuse;segments articulate to petiolules, leaving wiry stalks when detached;blade tissue glabrous abaxially. Fertile pinnae on 0.5-1.0 cm stalks, oblong, 1-pinnate, 3-14 × 2.5-6 cm;ultimate segments ovate to lanceolate-oblong, fringed with fertile lobes, otherwise similar to sterile segments (Flora of North America Editorial Committee, 2015).
L. microphyllum is a species of climbing fern native to large parts of tropical and subtropical Africa, Asia and Oceania. This species was originally introduced into the USA for ornamental purposes in the mid-1900s. However, it has aggressively invaded forest dominated wetlands, notably in southern and central Florida, USA where it is one of the most important invasive species. This climbing fern causes significant ecological impacts, forming thick mats which climb over and smother undergrowth, shrubs and even tall trees and modify fire regimes so that ground fires are carried into the forest canopy.
The following description is from e Floras (2013)
Medicago polymorpha is a herbaceous legume that is native to western and central Asia and countries around the Mediterranean, and has been introduced widely around the world. It is found in particular in regions with a Mediterranean climate, but is by no means confined to them. Introduction has been a result of accidental transport of the spiny seed pods and probably also of deliberate introduction as a fodder plant;the relative importance of these two means of spread cannot be determined. The species can be a useful pasture plant, in particular because of its nitrogen-fixing ability, but in other places it is considered to be an invasive weed;it can sometimes be toxic to livestock, and the seed pods can be a serious contaminant of wool.
M. heterophyllum is an aquatic plant that has submerged vegetation with emergent flowering spikes. Plants hermaphroditic, occasionally monoecious. Stem stout, to 100 cm;internodes crowded. Submerged leaves 4- or 5-whorled or scattered, pectinate, oblong in outline, (1.5-)2-4 × 1-3 cm;segments in 5-12 pairs, filiform, 0.5-1.5 cm. Inflorescence a terminal spike of 4-whorled flowers, 5-35 cm, in monoecious plants lowermost flowers female, uppermost ones male;bracts persistent, eventually reflexed, lanceolate to oblong or obovate, 4-18 × 1-3 mm, margin sharply serrulate;bracteoles ovate, ca. 1.2 × 0.6 mm, margin serrate. Petals 1.5-3 mm. Stamens 4. Fruit 4-loculed, subglobose, 1-1.5 mm;mericarps with 2 finely tuberculate ridges abaxially, apex beaked (Flora of China Editorial Committee, 2012).
Morphological keys (such as Aiken, 1981) are available but rely mostly on characters of flowers and fruits, which may not be present, as M. heterophyllum rarely flowers. It can best be recognised by its dense underwater growth and undivided, serrate emergent leaves (Q-bank, 2015).
Genetic identifications using the nuclear ribosomal DNA internal transcribed spacer regions (ITS) have become common (Moody and Les, 2002;Thum et al., 2006).
M. heterophyllum is an aquatic plant native to southeast USA. It is considered invasive throughout New England and northwest USA and as an emerging invader in Europe because of its tendency for uncontrolled growth and subsequent formation of dense mats of submergent vegetative material throughout the water column and at the water surface. These mats prevent water flow, reduce sunlight, reduce oxygen availability, and impede swimming, boating and fishing. M. heterophyllum is banned from sale in some New England states and Washington state.
Branchlets terete, glabrous;tendrils 5-9-branched, young apex curving, later developing into suckers. Leaves palmately 5-foliolate;petiole 5-14.5 cm, petiolule short or nearly absent, glabrous;leaflets obovoid, obovate-elliptic, or elliptic, 5.5-15 × 3-9 cm, glabrous or veins abaxially sparsely pilose, lateral veins 5-7 pairs, veinlets inconspicuously raised, base cuneate or broadly cuneate, margin with rough teeth, apex cuspidate. Paniculate polychasium pseudoterminal, with conspicuous rachis, 8-20 cm;peduncles 3-5 mm. Pedicel 1.5-2.5 mm, glabrous. Buds elliptic, 2-3 mm, apex rounded. Calyx entire. Petals elliptic, 1.7-2.7 mm, glabrous. Filaments 0.6-0.8 mm;anthers elliptic, 1.2-1.8 mm. Disk inconspicuous. Ovary coniform;stigma not expanded. Berry 1-1.2 cm in diameter, 1-4-seeded. Seeds obovoid, base with short, acute rostrum, apex rounded (Flora of China Editorial Committee, 2017).
Specimens with 7-foliolate leaves have been collected from sandy areas in Dare County, North Carolina (Flora of North America, 2015).
P. quinquefolia is a woody, deciduous vine widely cultivated as an ornamental that has escaped from gardens to become naturalized and invasive in natural habitats. It is a fast-growing plant that climbs to a height of 15-20 m on trees, poles or other structures. The tendrils of this vine end in small adhesive pads which stick firmly to stone or bark. This vigorous vine grows forming dense blankets of foliage that shading-out herbs, shrubs, and trees in the canopy and understory. Currently it is regarded as an environmental weed in Australia and it is listed as invasive in several countries in Europe, China and in Cuba (Oviedo and Gonzalez-Oliva, 2015;DAISIE, 2017;Flora of China Editorial Committee, 2017;GRIIS, 2017;Weeds of Australia, 2017). Within the UK it is listed as an invasive non-native species on Schedule 9 in the UK Wildlife and Countryside Act.
P. densum is a perennial grass;culms 0.8-2 m high, robust, thick and succulent at the base, compressed, the nodes glabrous to densely appressed-hirsute;sheaths much longer than the internodes, keeled, broad and loose, glabrous or hirsute on the collar, the margins sometimes ciliate toward the summit, the lower ones equitant, purplish, spongy, reticulate in drying;ligule 1.5-3 mm long;blades 50-100 cm long, 1-2 cm wide, firm, folded at the base, long-acuminate, glabrous with a few hairs just above the ligule, the margins sharply serrate;panicles 12-40 cm long, rather narrow, tapering, dense, composed of 50-100 crowded, finally spreading racemes, the lower ones 5-9 cm long with conspicuous tufts of hairs in the axils;rachis 1.2-1.5 mm wide, sharply serrate, the margins papillose-ciliate with rather stiff hairs 2-5 mm long;spikelets 1.9-2.2 mm long, paired, on slender scabrous pedicels, suborbicular or obovate, sometimes tinged with purple;glume and sterile lemma equal, thin, glabrous;fruit covered or slightly exposed, 1.8 mm long, pale, minutely striate (Flora of Panama, 2016).
P. densum is a fast-growing grass species naturally distributed across Central and South America and the West Indies (Brummitt, 2013). Within its native distribution range, P. densum is described as a weed of roadsides, disturbed moist places, moist savannas, low open grounds, marshes, swamps and drainage ditches (Hitchcock, 1971;Quattrocchi, 2006). It is listed as invasive only in Cuba (Oviedo Prieto et al., 2012) and as a noxious weed in the region of Bahia in Brazil (Mori et al., 1980).
The following description of P. quadrifida is taken from Flora Zambesiaca (2014).
P. quadrifida is a succulent, annual, mat-forming species. The native range of this species is not clearly defined and many describe it as pantropical. P. quadrifida has been introduced into a number of new countries around the world. There are no records of P. quadrifida behaving as an invasive weed outside its native range, where it acts as an agricultural weed. This species is not particularly competitive but, as a halophyte, it is resistant to drought and areas of low soil fertility and therefore readily becomes dominant under such circumstances. There is also a large amount of variation within this species enabling it to adapt to new environments. As a plant with food and herbal properties, there are possibilities for deliberate introduction of this species into new areas where it could be problematic.
In its native range of India, P. quadrifida is a significant weed in maize (Zea mays) (Subbulakshmi, 2009) and onions (Allium cepa) (Kachare et al., 2005). It is also a major weed of green gram (Vigna radiata) in the ‘summer’ season in India but less in black gram (V. mungo) in the monsoon season (Singh et al., 1991). It also occurs in pigeon pea (Cajanus cajan), cabbage (Brassica oleracea var. capitata), cauliflower (Brassica oleracea var. botrytis), cucurbits (Cucurbitaceae family) and teosinte (Zea species) in India and in coffee (Coffea species) in Kenya and sorghum (Sorghum bicolor) in Sudan.
P. crispus is an herbaceous, submersed aquatic species that typically grows with stem up to 1m long. Its sessile, linear leaves are light to dark-green. They are typically from 1.2-9 cm long, 4-10 mm wide and are spirally arranged on flattened cauline stems. Leaves are homophyllous, often undulate, with obtuse apices and 3-5 veins. Margins are finely serrate. Lacunae are conspicuous and occur in rows of 2-5 along the midrib of the leaf. Stipules are not fused to the leaf and persistent, though inconspicuous. Leaves and stem are lax;the plant is either entirely submersed or nearly entirely submersed with some leaves floating at the surface. Nodal glands in this species are entirely absent. Inflorescences are unbranched and emersed, generally terminal (Flora of North America Editorial Committee, 1993). Flowers are tiny, with four petal-like lobes on spikes 1-3 cm long on stalks up to 7 cm long (Washington State Department of Ecology, 2008). Sessile reddish-brown single-seeded fruits are unkeeled and measure 6 x 2.5 mm. Fruits have a small recurved beak that measures 2-3 mm. Embryo has full spiral. Short, bur-like hardened turions, in which internode length is extremely shortened, measure 1.3-3 by ~2 cm, are common and can be either apical or axillary (Flora of North America Editorial Committee, 1993;USACE, 2002).
Formal aquatic plant surveys are generally necessary for the early detection of this species.
Similarities to Other Species/Conditions
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P. crispus is easily distinguished from other pondweeds by leaf and fruit morphology, phenological characteristics, and turion production (Iida et al., 2004). P. crispus is unique in that its leaf margins are finely serrate. Difficulties in identification may occur very early or late in the growing season, when turions are germinating. At these times, the plant develops a winter growth form with very slender, limp, blue-green leaves (Bolduan et al., 1994). Serrations are present in the winter growth form, though are not as conspicuous. However, members of the genus Potamogeton hybridize readily, and produce individuals with intermediate morphological characteristics (Kaplan and Fehrer, 2004).
Prevention and Control
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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
The vegetative propagules of this species are very easy to spread. Therefore, educational programs are usually necessary to decrease this form of human-mediated spread. Teaching users how to clean equipment in a way that decreases the chance of transmission is one way to lessen the impact of the human vector. Several of the USA states have legislated regulation of the purchase, transportation, and introduction of this species.
This species produces turions prolifically, and because the turions can stay dormant yet viable for at least 2 years (Tomaino, 2004), rapid response to decrease turion deposition is integral to successful management.
Numerous educational campaigns have been directed at informing the public about the danger of aquatic invasive species. Agencies in areas in which P. crispus is particularly problematic commonly distribute informational materials about its identity as well as how to report new invasions. Other educational campaigns have been directed towards informing the public about how to clean equipment in order to prevent the transportation and spread of invasive species.
No reports of eradication exist in the literature.
Cultural control and sanitary measures
Turions are easily transportable and can remain dormant for up to 2 years. Thus, it is extremely important to decrease the instances of accidental introduction by addressing humans as a vector. By establishing guidelines on how to properly clean equipment, dispose of water, and identify target plants, it is likely that instances of accidental transportation and release will be fewer.
Mechanical harvesting may be used to obtain some nuisance relief, but reviews of efficacy of control are mixed. In Michigan, USA the dominance of P. crispus was only reinforced by harvesting at the expense of natives (Bolduan et al., 1994), whereas it has been shown elsewhere that early season cutting at the sediment surface prevented turion production (ISSG, 2006). Some have used winter drawdowns as a means of control, but the literature reports no significant impact of overwinter drawdown on P. crispus (Nichols and Shaw, 1986). Shallow dredging also has mixed reviews, at times there seems to be little effect, and in some cases lasting control has been achieved (Tobiessen and Snow, 1984;Tomaino, 2004).Other mechanical methods including benthic barriers, hand removal, rotovation and shading have been reported as successful (USACE, 2002).
Screening has been used to stop the movement of turions. However, because plants can spread via fragments, much attention has been given to decreasing human-mediated dispersal. The plant is on a number of state noxious lists. Some states have put in place legislation to regulate the sale, transportation and introduction of P. crispus.
P. crispus is sensitive to 2,4-D, especially during early spring (Wolf and Madsen, 2003;Belgers et al., 2007). P. crispus is susceptible to endothall-based herbicides (Skogerboe and Getsinger, 2002). It is also suggested that treatments occur in early spring in order to lessen the impacts on the native plant community (ISSG, 2006). The herbicides fluridone and diquat have also been used and in general, chemical treatments provide relief for one growing season (ISSG, 2006).
P. crispus is a productive, submersed macrophyte that is non-native and invasive in temperate areas of North America, New Zealand, and southern South America (Kaplan and Fehrer, 2004). The species is listed as a noxious or prohibited weed in several areas of the USA (USDA-NRCS, 2008). The species is a cold weather strategist, which allows it to establish early in the growing season (Nichols and Shaw, 1986). Unlike most macrophytes, P. crispus plants typically die back by early summer and lie dormant until temperatures decrease again in autumn (Bolduan et al., 1994). It is also a productive species that tends to form monocultures, thereby decreasing the amount of light available to other species (Engelhardt, 2006). However, its impact on native species is disputed in the literature. Some authors state that early emergence helps P. crispus out-compete natives, while others aver that its characteristic summer die-back removes it from such competition (Bolduan et al., 1994). However, this documented summer senescence is problematic, as the inevitable decay of organic material and resultant nutrient release can stimulate algal blooms and lead to dissolved oxygen crashes. Additionally, this species is particularly hard to control due to its prolific production of turions (Yeo, 1966).
Given this species’ tendency to grow in monocultures with high productivity, it has been reported to cause decreases in biodiversity by out-competing native plants (Tomaino, 2004). However, it should be noted that the impact of this species on the native community is disputed, with some authors concluding that because the plant acts like a winter annual it does not negatively impact native species (Bolduan et al., 1994). It can be productive, but is not generally reported as a nuisance in its native range.
R. rosifolius is an erect or spreading shrub, 1–3 m long. Branchlets grayish brown or dark reddish brown, terete, soft hairy or subglabrous, with straight to curved prickles and yellowish glands. Leaves imparipinnate, usually 5–7-foliolate;petiole 2–3 cm, petiolule of terminal leaflet 0.8–1.5 cm, lateral leaflets subsessile, petiolule and rachis with soft hairs and sparse, minute prickles, sometimes subglabrous, with yellowish glands;stipules linear or lanceolate to ovate-lanceolate, 0.8–1.2 cm × 1.5–3.5 mm, sparsely soft hairy;blade of leaflets ovate or ovate-elliptic to lanceolate, 4–7(–10) × 1.5–5 cm, both surfaces pilose, glabrescent, with yellow glands, abaxially with sparse, minute prickles along the midvein, base rounded, margin sharply incised doubly serrate or coarsely doubly serrate, apex acuminate. Inflorescences terminal or in leaf axils, 1- or 2-flowered;bracts linear or lanceolate, 5–9 mm, puberulous. Pedicel (1–)2–3.5 cm, with ± soft hairs and sparse, minute prickles, sometimes glandular. Flowers 2–3(–5) cm in diameter. Calyx abaxially soft hairy and glandular;sepals triangular-lanceolate or ovate-lanceolate, 0.8–1.2(–1.4) cm × 4–6 mm, apex long caudate. Petals white, oblong, narrowly obovate, or suborbicular, 0.8–1.5 × 0.8–1.2 cm, abaxially shortly hairy, base clawed, apex obtuse. Stamens many, shorter than petals;Pistils to 2 mm, shorter than stamens;ovary glabrous, sometimes glandular;styles glabrous.. Aggregate fruit red, ovoid-globose or narrowly obovoid to oblong, 1–1.5 × 0.8–1.2 cm, glabrous, with few glands;pyrenes deeply foveolate (Flora of China Editorial Committee, 2014).
R. rosifolius is a shrub which occurs naturally in forest margins, disturbed areas, landslide-affected land, abandoned fields, pastures, and roadsides. This species can invade the understory of moist and montane forests, especially areas in natural and artificial openings in primary and secondary forests. It is included in the Global Compendium of Weeds (Randall, 2012) and it is also listed as invasive in Brazil, Tanzania, Puerto Rico, Cuba and Hawaii (see distribution table for details;Oviedo Prieto et al., 2012;I3N-Brazil, 2014;PIER, 2014;Rojas-Sandoval and Acevedo-Rodríguez, 2014). In St. Lucia and Hawaii, it can completely cover wet open areas and exclude native species (Motooka et al., 2003;Graveson, 2012). In Brazil, this species invades principally wet and sunny habitats with more than 1800 mm of mean annual precipitation, displacing desirable plants and interfering with passage and use of the land (I3N-Brasil, 2014). In Africa, it invades savanna, coastal bush, disturbed grassland, forest margins, roadsides and riverbanks (BioNET-EAFRINET, 2014).
Adapted from the Flora of North America Editorial Committee (2015)
Many tumbleweeds (genus Salsola, section Kali) are important roadside, rangeland and agricultural weeds native to much of Europe, North Africa, the Middle East, Central Asia, China and Australia. Species have also been widely introduced accidentally as contaminants of crop and pasture seeds, and tumbleweed has become a widespread weed in Canada, USA, Mexico, Chile, China, Indonesia, Japan, Australia and New Zealand. S. kali and it many confused synonyms (including S. tragus and others which are disputed, such as S. iberica and S. australis) are common agricultural, rangeland and environmental weeds with multiple and important impacts. Major efforts have been made regarding mechanical, chemical and, more recently, biological control.
S. kali is common weed of a very wide range of agricultural crops, as well as grassland plants.
The following description is from Flora of China Editorial Committee (2016)
S. alata is a shrub or small tree that is used as an ornamental and a cultivated plant throughout its range (Irwin and Barneby, 1982;PROTA, 2016). The species is reported as escaping from cultivation and becoming a weed in pastures, disturbed areas, orchards, plantations and shrublands (Irwin and Barneby, 1982;ILDIS, 2016). Livestock do not eat it, so the species has the potential to spread rapidly without control (ILDIS, 2016). It is reported as invasive in Asia (Hong Kong, Philippines, Singapore), East Africa and Oceania (Australia, Cook Islands, Federated States of Micronesia, Fiji, French Polynesia, Galapagos Islands, Guam, Hawaii, Palau, Papua New Guinea, Samoa and Tonga) (PIER, 2016). It is regarded as a significant environmental weed in the Northern Territory of Australia (Weeds of Australia, 2016). Risk assessments prepared for both Australia and the Pacific classed it as high risk (PIER, 2016).
The following description is taken from The Flora of China Editorial Committee (2017).
S. hirsuta is an herbaceous plant native to the Americas. It has been introduced into several countries in Asia, Africa and Oceania where it has naturalized. S. hirsuta typically colonises areas of disturbed land such as roadsides, waste land and riparian areas. Very little information is available with regards to the environmental impacts of this species, although it is listed as invasive in Queensland (Australia), South Africa and Eastern Africa. The closely related species S. obtusifolia and S. tora are both serious weeds worldwide. and S. hirsuta possesses similar attributes to those which make these species invasive.
Shrubs, small trees, or trees, 7-20(-40) m tall. Young parts generally puberulent;branchlets reddish brown when dry. Leaves 12-20 cm;stipules early caducous, linear;rachis and petiole puberulent, with a long, ovoid gland on rachis between lowest pair of leaflets (often early caducous);leaflets 10-26(-50) pairs, linear-oblong or oblong, 1.2-4 × 0.6-0.8 cm, both surfaces puberulent or adaxially glabrous, apex obtusely rounded, mucronate, slightly oblique. Racemes several, arranged in a terminal, leafy panicle 10-20(-40) cm;peduncle and pedicels puberulent. Flowers 2.5-4 cm in diam.;bracts ovate, ca. 2 mm, tomentose. Sepals greenish yellow when mature, slightly unequal, 5-6 mm. Petals yellow, ovate-oblong, 1-2(-3) cm, glabrous. Fertile stamens 7, 3 larger, with filament ca. 10 mm and anthers 6-7 mm, staminodes 3, tiny. Ovary linear, glabrous. Legume dark brown, flat, broadly linear, obtuse. Seeds 30-60, flattened, ca. 6 mm (Flora of China Editorial Committee, 2014).
S. multijuga is a shrub or tree which is native to the northern part of South America but has naturalized in tropical regions around the world, where it has been introduced for cultivation as an attractive ornamental (Flora of China Editorial Committee, 2014;PIER, 2014). The species has escaped from cultivation and is listed in the Global Compendium of Weeds as a weed, cultivation escape, and garden thug (Randall, 2012). In addition to its ability to tolerate many soil types, it forms a persistent seed bank and its seeds are easily dispersed both by humans and wind. Once established in new areas, the species has been known to naturalize quickly. The species is known to be invasive in Hawaii (PIER, 2014).
The following description comes from Flora of China Editorial Committee (2015)
S. sesban is a deciduous, short-lived perennial shrub or tree, indigenous to north-east Africa and often also described as native to parts of southern Asia. It is cultivated widely for fodder and forage, and is reported as an invasive species in Israel and the U.S. state of Hawaii (PIER, 2012;Dufour-Dror, 2013). It has become naturalized in many of the countries where it is cultivated, and is characterized by very rapid early growth.
Herb or shrub to 1.5 m tall;twigs viscid-villous with long simple hairs, armed with yellow or green, acicular spines which in age become flattened, recurved, woody, 2.5 cm long;stems fistulose. Leaves 6-20 cm long, broadly ovate, pin- natifidly lobed, the base truncate to deeply cordate, both sides villous with long, simple, glandular hairs, short-stalked glands and sessile, long-radiate stellae with ascending radii, armed with flattened acicular spines to 3 cm long;petioles 3-7 cm long, sparingly armed. Inflorescence lateral, several-flowered, a short raceme on a short (to 10 mm long) peduncle;pedicels 5-12 mm long, becoming stout and somewhat longer in fruit, viscid-villous to lanate, armed or not. Flowers with the calyx unarmed, deeply lobed, the lobes lanceolate, pubescent outside, 3-6 mm long;corolla violet, showy, exceeding the calyx 2-3 times in bud, 3-4 cm across, lobed about halfway;filaments very short, the anthers 10-12 mm long, linear-oblong and tapering. Fruit orange or yellow, 4-7 mm long, ovoid, often with a 2 cm long, nipple-like apex, and sometimes.bearing one or more nipple-like protrusions at the base;seeds compressed-lenticular, 5-7 mm across, not winged, finely rugose, shiny [Flora of Panama, 2014].
S. mammosum is an annual or tender perennial plant with poisonous fruit, reported as invasive in Cuba (Oviedo Prieto et al., 2012) as well as in the Philippines (Merrill, 1923), Fiji, Tonga, and parts of Hawaii (Space and Flynn, 2002;PIER, 2014). It is listed as an ‘agricultural weed’, ‘causal alien’, ‘naturalised’ and ‘weed’ in the Global Compendium of Weeds (Randall, 2012). The species is considered native to Central and South America (Acevedo-Rodriguez and Strong, 2012) and possibly the Caribbean (Nee, 1979;PBI Solanum Project, 2014), but has been introduced to the Old World tropics for ornamental use as well as medicinal and food purposes (Lim, 2013), and has potential to escape cultivation (PBI Solanum Project, 2014). It is an annual or short-lived perennial (PBI Solanum Project, 2014) that reproduces by seeds, which may be dispersed by both biotic and abiotic factors, as they are encased in bright yellow-coloured, large, spongy fruit that can float on water (Chiarini and Barboza, 2007;2009). The species is a known weed in Jamaica (Holm et al., 1979), Java (Randall, 2012), and Florida (Medal et al., 2009), and is spontaneous where it occurs in Brazil (Forzza et al., 2010).
Although it is frequently used as an ornamental, S. mammosum is known to be poisonous to mammals (USDA-ARS, 2014) and is included in the FDA Poisonous Plant Database (US-FDA, 2014).
Plants acaulescent or short-stemmed, commonly suckering, trunks less than 2 m;rosettes not cespitose, 10–20 × 20-37 dm. Leaves erect, spreading to ascending, occasionally reflexed, 80–200 × 15-25 cm;blade light green to green or glaucous-gray, sometimes variegated or cross-zoned, narrowly to broadly lanceolate, smooth, rigid;margins nearly straight or undulate to crenate, armed, teeth single, 5-10 mm, 1-4 cm apart;apical spine dark brown to grayish, conical or subulate, 2-6 cm. Scape 5-9 m. Inflorescences paniculate, not bulbiferous;bracts persistent, triangular, 5-15 cm;lateral branches 15-35, horizontal to slightly ascending, comprising distal 1/3-1/2 of inflorescence, longer than 10 cm. Flowers erect, 7-10.5 cm;perianth yellow, tube funnelform to cylindric, 8-20 × 12-20 mm, limb lobes erect, subequal, 20-35 mm;stamens long-exserted;filaments inserted above mid perianth tube, erect, yellow, 6-9 cm;anthers yellow, 25-35 mm;ovary 3-4.5 cm, neck constricted, 3-6(-8) mm. Capsules short-pedicellate, oblong, 3.5-8 cm, apex beaked. Seeds 6-8 mm (Flora of North America Editorial Committee, 2016).
A. americana is a large, rhizomatous succulent that grows in a wide range of habitats and soil types. Additionally, it is tolerant to salt spray, high temperatures, and extreme drought. Because this species spread by seeds, but also vegetatively by bulbils and rhizomes, it has the potential to escape from cultivation and rapidly colonize disturbed sites, roadsides, bare sand and coastal areas (ISSG, 2016). Currently, A. americana is considered a serious environmental weed by the IUCN (ISSG, 2016) and it is listed as invasive in many countries in Europe as well as in China, Japan, South Africa, Namibia, Tanzania, Bermuda, Australia, New Zealand, and New Caledonia among others (BioNET-EAFRINET, 2016;ISSG, 2016;DAISIE, 2016;PIER, 2016;Weeds of Australia, 2016). It is also known to have become invasive in Ethiopia, Kenya, Malawi, Rwanda, and Uganda.
A. americana negatively impacts populations of native and endangered plant species such as Cheirolophus crassifolius and Cremnophyton lanfrancoi on Malta and species such as Crambe wildpretii, Crambe pritzelii, and Asparagus arborescen s on the Canary Islands (ISSG, 2016).
A. capillaris is a low-growing, rhizomatous, perennial grass. It forms dense swards of quite fine leaves that taper almost directly from the ligule down to the finely pointed tip. The flowering panicle is finely branched with numerous very small spikelets forming a reddish-purple haze over the mat of leaves. Culms are tufted, geniculate or decumbent and rooting at base, 20-70 (occasionally 100) cm tall. Leaf sheaths are smooth with linear blades, flat or inrolled, 2-15 cm x 1-4 mm, scabrous or nearly smooth with acuminate apex. The ligule on non-flowering shoots is 1-2 mm, shorter than wide and truncate. The panicle is elliptic in outline, up to 20 cm long, open and very lax with 2-5 spreading branches per node. Branches of the panicle are capillary, 1.5-3.5 cm, with purplish brown spikelets (1.5-2.5mm). Glumes are elliptic-lanceolate, subequal or lower glume slightly longer, lower glume scabrid along keel, the upper glume often smooth with acute apex. The entire plant is hairless. Seeds are small and brown;roots have scaly rhizomes and occasionally stolons (Edgar and Forde, 1991;Zheng et al., 2006;Quattrocchi, 2006;Gateley, 2015;Flora of China Editorial Committee, 2016;Garry Oak Ecosystems Recovery Team, 2016;New Zealand Plant Conservation Network, 2016).
Common bent, Agrostis capillaris, is a typical and often abundant species in grasslands on acidic or neutral soils. It is native and widespread throughout most parts of Europe, western and southwestern Asia and North Africa. Within its native range the species is often abundant in nutrient poor pastures, along roadsides or on disturbed ground. A. capillaris has been intentionally introduced as a pasture grass and as a turf grass for lawns, in particular for golf courses, into a number of countries and has become widespread in North America, Australia, New Zealand and parts of South America. It has been recorded as invading native grasslands in part of its exotic range, including prairies in North America.
A. capillaris has not been reported as a weed in specific cropping situations, but can invade pastures and other grasslands.
Adapted from Flora of North America Editorial Committee (2014)
O. engelmannii is a species of cactus, and one of many Opuntia species that have been introduced from their native ranges in the Americas and become naturalized and invasive, particularly in Australia, southern and eastern Africa, and the Mediterranean region. However, O. engelmannii is also reported as a noxious weed in Texas and elsewhere in its native range, where it has undergone control for almost a century. Contrastingly, in other US states such as Arizona it is noted as potentially endangered. Noting new records (e.g. Saudi Arabia), further occurrences not yet reported in other countries are possible, and further spread is likely. However, where it is invasive in Australia and South Africa, it has been successfully brought under control, as with other Opuntia species, with the use of biological control agents.
The following description is from the Flora of China (Flora of China Editorial Committee, 2010)
Amorpha fruticosa is a fast-growing, deciduous shrub that grows in wetlands and disturbed habitats. It is native to North America but has spread across Asia and Europe, likely through its use as an ornamental plant. It is now generally accepted to be among the most invasive alien species in Europe. It has a high reproductive capacity, forms dense thickets and outcompetes native flora, changing successional patterns and reducing biodiversity. Repeated cutting and mowing can help to control populations of this species and in disturbed habitats, some herbicides have been successful in controlling its spread.
Plants glabrous or sparsely pubescent in the distal younger parts of stems and branches. Stems erect or sometimes ascending proximally, much-branched and bushy, rarely nearly simple, 0.3-1(-2) m;each node with paired, divergent spines (modified bracts) to 1.5(-2.5) cm. Leaves: petiole ± equaling or longer than blade;blade rhombic-ovate, ovate, or ovate-lanceolate, 3-10(-15) × 1.5-6 cm, base broadly cuneate, margins entire, plane or slightly undulate, apex acute or subobtuse. Inflorescences simple or compound terminal staminate spikes and axillary subglobose mostly pistillate clusters, erect or with reflexed or nodding tips, usually green to silvery green. Bracts of pistillate flowers lanceolate to ovate-lanceolate, shorter than tepals, apex attenuate. Pistillate flowers: tepals 5, obovate-lanceolate or spatulate-lanceolate, equal or subequal, 1.2-2 mm, apex mucronate;styles erect or spreading;stigmas 3. Staminate flowers: often terminal or in proximal glomerules;tepals 5, equal or subequal, 1.7-2.5 mm;stamens 5. Utricles ovoid to subglobose, 1.5-2.5 mm, membranaceous proximally, wrinkled and spongy or inflated distally, irregularly dehiscent or indehiscent. Seeds black, lenticular or subglobose, 0.7-1 mm diameter, smooth, shiny (Flora of North America, 2015).
A. spinosus is a serious weed in tropical and subtropical regions of the world. For instance, it is a troublesome weed in agricultural areas, pastures, and orchards in Africa, Asia, Europe, Australia, and the Pacific region. In those regions, it is also a serious environmental weed in disturbed sites, secondary forests, along forest edges, and around water troughs (Lemmens and Bunyapraphatsara, 1999;Motooka et al., 2003;PIER, 2015;PROTA, 2015;USDA-ARS, 2015). The plant has large thorns which make it unpalatable for grazing livestock and make weeding difficult in parts of the world where hand weeding and harvest are done by hand. Like other amaranths, it produces large numbers of seeds, which can mature after the plant has been cut, and remain viable for long periods.
The following description is taken from the Flora of China (Chen and Pipoly, 1996). Shrubs 1-2 m tall, with angular branchlets, 3-4.5 mm in diameter, glabrous, conspicuously black, punctate-lineate, longitudinally ridged. The petiole is marginate, 5-10 mm long;and the leaf blade is 6-12(-16) cm long and 3-5(-7) cm broad, oblanceolate or obovate in shape, subleathery, dull and densely punctate abaxially, especially along the margin, base cuneate, margin revolute, entire, apex obtuse or acute;with lateral 12-34 veins on each side of the midrib, marginal vein present. Inflorescences are axillary or subterminal on basally thickened lateral branches, subumbellate or umbellate. Flowers are leathery, pink or white, 6(-8) mm. Pedicel ca. 1-2 cm, minutely and densely white verruculose, densely punctate. Sepals broadly ovate, ca. 1 mm, densely black punctate, base rugose and subauriculate, margin subentire, scarious, minutely ciliate, apex rounded. Petals almost free, broadly ovate, densely punctate, glabrous, margin hyaline, scarious, entire, apex long attenuate. Stamens subequalling petals;anthers linear-lanceolate, punctate dorsally, longitudinally dehiscent, transversely septate-lobed, apex apiculate. Pistil as long as petals;ovary glabrous, pellucid punctate;ovules numerous, multiseriate. Fruit subglobose, red or purplish black, ca. 8 mm in diameter, minutely punctate, fleshy.
A. humilis is a perennial shrub, 1-2(-5) m tall, glabrous. Branchlets terete, 5-7 mm in diameter, glabrous. Petiole canaliculate, 6-10 mm;leaf blade obovate, elliptic, or rarely oblanceolate, 15-18 × 5-7 cm, leathery, glabrous, inconspicuously pellucid punctate, scrobiculate, base cuneate and minutely decurrent, margin entire, apex broadly acute to obtuse;lateral veins ca. 12 on each side of midrib, marginal vein absent. Inflorescences terminal, rarely terminating lateral branchlets, subumbellate or cymose in pyramidal panicles, 8-17(-20) cm. Flowers leathery, pink or purplish red, 5-6 mm. Pedicel 6-10 mm, approximately 1.5 cm in fruit. Sepals broadly ovate, 1-2 mm, glabrous, punctate, base subauriculate, margin entire, apex acute. Petals nearly free, broadly ovate or ovate, glabrous, inconspicuously pellucid or orange punctate, glabrous. Stamens subequalling petals;filaments about half of anther length;anthers oblong-lanceolate, punctate dorsally, apiculate. Pistil equaling petals;ovary punctate, glabrous;ovules numerous, in 3 series. Fruit dull red or purplish black, globose, approximately 6 mm in diameter, densely punctate (Flora of China Editorial Committee, 2015).
Ardisia humilis is an ornamental shrub that is native to southern China, the Philippines and Vietnam. It has been intentionally introduced in some tropical and subtropical regions of the world where it may escape from cultivation, becoming a potential problem in moist lowland areas. Currently, this species is only listed as invasive in Cuba and Florida, USA. Most Ardisia species (including A. humilis) produce fleshy fruits that are consumed and dispersed by birds and small mammals, and are shade tolerant species with the potential to form monospecific stands in moist areas displacing native vegetation.
Herbs hermaphroditic. Stems climbing, much branched, to several metres, slightly woody near base;branches spreading horizontally, with branchlets and cladodes arranged in one plane, frond-like. Cladodes in fascicles of 10-13, 4-5 mm, very slender, slightly trigonous. Leaf spur short, occasionally spinescent on main stems. Inflorescences developing after cladodes. Flowers solitary or in clusters of 2 or 3;pedicel short, articulate at middle. Perianth white;segments widely spreading, lanceolate-oblong, approximately 7 mm. The fruit are small rounded berries (4-5 mm across) and are initially green in colour. These berries turn black or bluish-black as they mature and contain one to three seeds (2.5-3.5 mm across) that are also black in colour (Flora of China Editorial Committee, 2016).
A. setaceus is a fast-growing climber species widely introduced throughout the tropics where it has become naturalized and invasive. Its extensive climbing habit, thorny stems, enlarged storage roots, and small black, bird-dispersed berries combine to make this a particularly difficult weed to eradicate (Imada et al., 2000). Currently, it is included in the Global Compendium of Weeds, where is listed as an environmental weed (Randall, 2012). It is also listed as invasive in Australia, New Zealand, Cuba, and Hawaii and on many islands in the Pacific Ocean (Healy and Edgar, 1980;Starr et al., 2002;Oviedo Prieto et al., 2012;PIER, 2016;Weeds of Australia, 2016).
In Australia, this species is regarded as an environmental weed and it was recently listed as a priority environmental weed. It is ranked among the top 100 most invasive weeds in Queensland where it is of particular concern in natural forests (Weeds of Australia, 2016). It Cuba it is considered an invasive species with the capability to “transform” natural habitats (Oviedo Prieto et al., 2012). PIER (2016) lists risk assessments prepared for Australia (Reject: score=16) and the Pacific (High risk: score=13).
The following description is taken from Flora of China Editorial Committee (2015):
B. cristata is a perennial subshrub to 2 m tall. Stems terete, branched, covered with soft trichomes. Petiole (0-)0.3-1 cm;leaf blade elliptic to oblong to ovate, 2-10 × 1-4 cm, both surfaces villous especially along veins, secondary veins 4-7 on each side of midvein, base cuneate and decurrent onto petiole, apex acute to sometimes acuminate. Inflorescences axillary short and dense cymes, shortly pedunculate;bracts absent;bracteoles variable, linear to linear-lanceolate, 2.4-6.5 × 0.5-1.5 cm, 3-7-veined, base cuneate, margin usually spiny but sometimes bristly pilose and becoming spinescent with age, apex acuminate. Outer calyx lobes ovate to narrowly elliptic to lanceolate, 1.2-2.5 × 0.5-1.3 cm, pilose, reticulately veined, margin spiny, apex mucronate;inner calyx lobes linear to lanceolate, 6-12 mm, 1-veined, margin scarious. Corolla purplish blue, 4.5-6.5 cm, outside pilose;tube basally narrowly cylindric then gradually widened;lobes oblong-elliptic, approximately 1.5 cm, equal. Stamens 4, didynamous;filaments pilose especially toward base;staminode 1, filament sparsely pilose. Ovary oblong-ellipsoid, glabrous;style linear, ca. 2.5 cm, glabrous;stigma slightly inflated. Capsule 1.2-1.8 cm, glabrous, 4-seeded. Seeds subglobose to ovoid, 4-5 × 4 mm.
While flowers are generally purple-blue, a white-flowered cultivar ‘Alba’ is present among both cultivated and naturalized populations (Weeds of Australia, 2015).
B. cristata is a fast growing perennial plant often cultivated in gardens for its showy flowers. This species has repeatedly escaped from cultivation and naturalized in disturbed sites, abandoned gardens, riverbanks, and along roadsides (Daniel, 2001;Flora of China Editorial Committee, 2015). B. cristata has the potential to tolerate a remarkable range of habitats including human-disturbed sites, wastelands, and xeric vegetation (Meyer and Lavergne, 2004). Currently, it is listed as an invasive plant species in Australia, Fiji, Hawaii, French Polynesia, Mauritius, Réunion, and Puerto Rico (Smith, 1991;Meyer and Lavergne, 2004;PIER, 2015;Rojas-Sandoval and Acevedo-Rodriquez, 2015). In Australia, it is listed as an environmental weed (Weeds of Australia, 2015).
The following description is taken from Flora of China Editorial Committee (2015).
B. prionitis is a small, erect, spiny shrub, up to 1.8 m tall with spines in lower leaf axils, branched. Stems and branches terete, smooth, lenticellate, glabrous. Petiole 1-2.5 cm;leaf blade elliptic to ovate, 4-10.5 × 1.8-5.5 cm, both surfaces pubescent when young but soon glabrescent, sparsely strigose along midvein, base attenuate and decurrent onto petiole, margin entire, apex acute. Flowers clustered in axils of upper leaves and/or bracts;bracts linear-oblong, 1.2-2.2 × 0.2-0.8 cm, margin ciliate, apex abruptly acuminate;bracteoles linear-lanceolate, to 1.4 × 0.2 cm, spine-tipped. Outer calyx lobes ovate-oblong, approximately 1.5 × 0.4 cm, apex mucronate;inner calyx lobes linear-lanceolate, approximately 1.3 × 0.2 cm, apex mucronate. Corolla yellow to orange, 2.4-4 cm, outside pilose;tube with narrow basal portion slightly shorter than throat;lobes ovate-oblong to orbicular, 8-10 × 6-7 mm, recurved. Stamens 4, longer pair approximately 1.1 cm with anthers approximately 3.2 mm, shorter pair approximately 1.5 mm with anthers approximately 1 mm. Ovary ovoid;stigma slightly enlarged, 2-cleft, exserted. Capsule ovoid, approximately 1.8 cm, contracted gradually at tip forming a beak, 2-seeded. Seeds ovate in outline, approximately 7 × 5 mm.
B. prionitis is a fast growing perennial plant widely commercialized as an ornamental to be planted in open sunny areas in gardens, yards, and parks. This species has frequently escaped in many tropical areas where it grows as a weed in disturbed areas, forest edges, rocky outcrops, near streams, along roads, and in overgrazed pastures (Francis, 2004). B. prionitis has the potential to grow in a wide range of climates and soil types. Additionally, it is adapted to grow in open, full sunny areas and in highly disturbed sites as well as in the understory of secondary forests.
B. prionitis has a great dispersal capability. It spreads sexually by seeds and vegetatively by stem fragments (PIER, 2015;PROTA, 2015;Weeds of Australia, 2015). Currently, B. prionitis is listed as invasive in Australia, Puerto Rico, Mauritius, the Seychelles and Reunión Island (Meyer and Lavergne, 2004;PIER, 2015;Rojas-Sandoval and Acevedo-Rodriguez, 2015;Weeds of Australia, 2015). B. prionitis has the potential to cause economic and environmental damage by forming dense thickets that displace native vegetation and prevent revegetation by native plants. Thickets and large infestations can impede the movement of stock, restrict access to waterways and reduce the aesthetic values of natural areas (Weeds of Australia, 2015). It is on an alert list for environmental weeds in Australia (Waterhouse et al., 2003), as it is suggested that the species has the potential to seriously degrade ecosystems.
Perennial, prostrate, slender, creeping herb, the often purplish stems rooting at the nodes and often forming mats. Leaves are ovate, 1-4 cm long;1-2 cm broad, acute at apex, rounded to sub-cordate at base, sessile, sub-succulent, glabrous except for ciliate margins;pale green;sheath tubular, 3-3.5 mm long, with a few long hairs at apex. Flowering in branches often somewhat ascending with leaves progressively smaller;flowers-clusters barely exserted beyond the sheaths in leaf-axils;bracts filiform, ciliate, 6-7 mm long. Sepals 3, linear lanceolate, greenish, 2-5 mm long, minutely pubescent;petals 4, oblong, whitish hyaline, slightly shorter than or equaling the sepals;stamens exserted, typically 3, but may vary in number from 0 to 6;filaments minutely ribbon-like, coiled at first, to 10 mm long;anthers rounded-elliptic or elliptic, basal on a reniform white connective ca. 0.5 mm long. Ovary 2-locular, pilose at apex, style filiform, up to 4.5 mm long, the stigma trifid (Howard, 1979) or penicillate (Hunt, 1983), 2 ovules per locule. Fruit is a lenticular capsule, approximately 1.7 mm long, splitting from apex to base;seeds 2 per valve, brown, approximately 1 mm, rugose (Acevedo-Rodríguez and Strong, 2005).
C. repens is an herbaceous species which has been widely cultivated as an ornamental in gardens and yards in tropical and subtropical regions from where it has escaped into natural areas. C. repens spreads vegetatively by cuttings, plant fragments, and/or discarded plants (Acevedo-Rodríguez and Strong, 2005). Once established, this species grows forming dense groundcover or “beds” on the forest floor preventing the germination and establishment of native plants. C. repens is listed as an invasive in South Africa, China, and Cuba (Foxcroft et al., 2007;Flora of China Editorial Committee, 2012;González-Torres et al., 2012), and it is also a common weed in Puerto Rico and US Virgin Islands (Más and Lugo, 2013).
C. pubescens is a large, erect, rapidly growing evergreen tree;up to 30 m tall, but most frequently reported as 4-10 m in height, attaining heights of 15 m on Santa Cruz, Galapagos (Shimizu, 1997);sparsely branched as lower branches shed, with young branches glabrous or pubescent. Bark brown, smooth;inner bark reddening when cut. Leaves deciduous, opposite, large, broadly elliptic-ovate to broadly oblong, 20-40 (-50) x 10-30 (-40) cm;upper surface light green, puberulent or glabrate, rather thin, membranous to papery, conspicuously veined (9-11 lateral pairs), margins entire, apex rounded, base broadly to narrowly cuneate, petioles 1.5-4.5 cm long, stipules ovate, caducous;lower surface with tufts of hairs in axils of lateral veins;old leaves reddish-orange. Flower numerous, in large panicles, rose-pink, fragrant;calyx densely appressed, pubescent, teeth deltate: heterostylous;in microstyled plants 5 exerted anthers alternate with corolla lobes and bifid stigma reaches half length of corolla tube;in macrostyled plants the situation is reversed with the stigma being exserted and the stamens hidden in pale pink corolla tube (1.0-1.2 cm long), which is villous within and comprising 5 spreading lobes, 4-5 mm long. Capsules ovoid-fusiform to oblong, 2-3 cm long;dehiscent from base to apex. Seeds 7-10 x 2-3 mm, with a broad ciliate wing. Note that this species description is a composite from several sources which vary considerably, especially in dimensions of the tree, leaves and seeds, emphasizing the variability of this species.
C. pubescens has been widely introduced throughout the tropics over the past 150 years because of its medicinal properties. However, it is only in small island systems, notably the Galapagos and Hawaii, that it has become invasive, after a relatively long period of adaptation. In the moist upland regions of these islands, it is beginning to have a significant impact on biodiversity affecting endemic species in both the flora and fauna.
C. pubescens is not a weed of agricultural crops, although there are reports of it invading Eucalyptus plantations in Hawaii (Wagner et al., 1999;Starr et al., 2003). In the Galapagos, it has invaded two of the upper vegetation zones (500-700 m), posing a threat to the endemic flora (Macdonald et al., 1988;Cronk and Fuller, 1995).
The following description is taken from Flora of China Editorial Committee (2016):
Herbs. Stems twining, slender, densely deciduous adpressed shortly villous. Leaves 2.5–5 cm, pinnately 5- to 7-foliolate, usually 5-foliolate;stipules small, linear, 2–5 mm;petiole 1.5–3 cm;stipels small, bristlelike;petiolules 1–2 mm;leaflets broadly elliptic or almost ovate, 2.5–5 x 1.5–3.5 cm, thinly papery or almost membranous, adpressed shortly villous or sometimes glabrous on both surfaces, lateral veins 4 or 5 pairs, base obtuse, apex obtuse, slightly emarginate, usually with mucro. Flowers large, solitary in axil;bracteoles green, small, suborbicular or obovate, membranous, with obvious reticulate veins. Calyx membranous, 1.5–2 cm, 5-lobed;lobes lanceolate, less than 1/2 of tube, apex acuminate. Corolla sky blue, pink, or white, to 5.5 cm;standard faintly white or orange in middle, broadly obovate, ca. 3 cm, base shortly clawed;wings and keels much shorter than standard, both clawed;wings obovate-oblong;keels elliptic. Ovary villous. Legume brown, linear-oblong, 5–11 x 0.7–1 cm, compressed, with long beak. Seeds 6–10, black, oblong, ca. 0.6 x 0.4 cm, with obvious strophiole.
There are varieties with double flowers and white flowers (Flora of Panama, 2016).
C. ternatea is a pasture legume also commercialized as a garden ornamental that has been widely introduced in agroforestry systems in tropical and subtropical regions of the world. Traits such as its high growth-rates, drought tolerance and adaptation to heavy clay soils suggest that this species could be used to improve natural grasslands (Staples, 1992). However, these traits have also helped this species to escape from cultivation and become an invasive species in river banks, creek lines, the margins of waterholes, irrigation channels, disturbed sites, roadsides and disturbed open woodlands and grasslands in Australia, Hawaii, the Galapagos Islands, Fiji, and on many islands in the Pacific region (Smith, 1985;Wagner et al., 1999;PIER, 2016;Weeds of Australia, 2016). C. ternatea is an aggressive colonizer of disturbed sites and open areas with the capability to displace and completely outcompete native vegetation (Weeds of Australia, 2016). Past risk assessments have given it a score of 7 (reject) for Australia and 9 (high risk) for the Pacific (PIER, 2016).
Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. The corresponding term for animal life is fauna. Flora, fauna, and other forms of life, such as fungi, are collectively referred to as biota. Sometimes bacteria and fungi are also referred to as flora, as in the terms gut flora or skin flora.
The sum total of the kinds of plants in an area at one time.