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).
Related invasive species
- Amaranthus spinosus
Related Farm Practice
- Flora
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.