L. dalmatica is a robust, glaucous, herbaceous perennial with taproots enlarged above, more or less woody, deeply penetrating (1.8 m or more into the ground), spreading by horizontal roots 5–20 cm below the surface, spreading up to 3.6 m from the plant. Adventitious offshoots from these roots are generally sterile, decumbent to weakly ascending, succulent, 3–40 per crown. Stems from the main crown are annual, 40–100 cm high, ascending to erect, more or less woody near the ground. Leaves are alternate, often in two’s or three’s on lower part of the stem, sessile, reflexed to ascending, entire, acute to acuminate at the tip, obtuse to cordate at the base, sometimes concave above, usually amplexicaul, somewhat leathery, glabrous and sometimes rugose, with 3–7 longitudinal veins on lower surface. The lower leaves are 1-5 cm long, up to 1 cm wide, linear to lanceolate;the upper leaves 3–6 cm long, 1-4 cm wide, lanceolate to very broad-ovate. Bracts are similar to upper leaves, or smaller. Flowers are in erect or nodding, simple racemes, usually loose, sometimes compact;15–55 cm long on pedicels 1–8 mm long. Five sepals, valvate or somewhat imbricate, erect, lanceolate acute to acuminate, 0.7–1.1 cm long, 0.2–0.4 cm wide, margins entire to somewhat undulate. The corolla, including spur 3.3–4.5 cm long, light yellow to yellow, rarely nearly white;tube 6–9 mm long, the upper lip bilobate, often somewhat helmet-shaped, the lower lip trilobate;spur tapered, 1.2–1.8 cm long, straight or slightly curved;four fertile stamens adnate in pairs, didynamous 0.8–1.5 cm long, one reduced staminode;pistil bicarpellate;ovary bilaterally symmetrical ca. 2 mm diameter at anthesis, abruptly narrowed to the terminal style;style filiform, erect, stigma single, terminal, hemispherical;numerous ovules in each locule;capsule long ovoid to nearly spherical, 4–10 mm long, 4–8 mm in diameter, dehiscing terminally on each carpel. Seeds black to purplish-brown, triquetrous or somewhat compressed, muricate-rugose on the surface, 0.7–1.3 mm wide, 30–170 per locule;each seed with narrow wing on the angles. The species is morphologically highly variable (this description simplified from Vujnovic and Wein, 2005, based on original by Alex, 1962).
Related invasive species
- Linaria dalmatica
Related Farm Practice
- Offshoots
- Light
L. dalmatica is a herbaceous plant native to western Asia and south east Europe. It is of particular concern in North America where it was introduced in the late nineteenth century. It has since spread across most of the western areas of the USA and Canada (De Clerck-Floate and Turner, 2013). There it has invaded rangelands, rights-of-way and natural habitats. It is classified as noxious in many of the western states of both countries. It is also classed as invasive in South Africa. Its success may be attributed to its high specific leaf area, aggressive root system, prolific seed production and the presence of alkaloids which discourages grazing by livestock, thus allowing it to become dominant (De Clerck-Floate and Turner, 2013).
The crops affected by L. dalmatica are mainly pasture and rangeland species, but alfalfa (Medicago sativa) and forest species such as ponderosa pine (Pinus ponderosa) may also be affected.