Amaranthus powellii

Erect or decumbent annual to 1.3 m high. Stems angled or grooved, glabrous to sparsely pubescent, sometimes reddish. Leaves long-petiolate, ovate to rhombic, lamina 1–10 cm long, 0.6–5 cm wide, entire; margin sometimes undulate; apex sometimes shortly mucronate. Inflorescence simple or few-branched, terminal and usually upper-axillary, the spikes to c. 8 cm long and 10–15 mm diam. Flowers unisexual; longest bracts and bracteoles, 4–6 mm long, broad and membranous at base, acuminate, strongly spinescent; tepals 3–5, oblong to narrowly oblanceolate, 2.5–3 mm long, acute; stamens as many as tepals. Utricle circumsciss, subequal to or slightly exceeding perianth; style-bases thick; seed discoid, 1–1.5 mm diam., brown, shiny. Flowers Dec.–May.