Compilation
Amaranthus tuberculatus

Stems erect to sometimes ascending or rarely prostrate, branched, rarely simple, usually (0.5–)1–2(–3) m. Leaves: petiole 1/4–1/2 length of blade; blade ovate or obovate proximally, oblong or elliptic to narrowly lanceolate distally, 1.5–15 × 0.5–3 cm, base cuneate, margins entire, plane, apex obtuse or rounded to acute. Inflorescences terminal, linear spikes to panicles, occasionally interrupted-moniliform, remote, globose glomerules. Bracts: of pistillate flowers 1–2 mm; of staminate flowers with inconspicuous to prominent midrib, 1–2 mm, apex acuminate to short-subulate. Pistillate flowers: tepals absent or 1–2, often rudimentary, 1–3 mm; style branches ± erect; stigmas 3. Staminate flowers: tepals 5, inner tepals with prominent midribs excurrent as rigid spines or not, equal to unequal, 2–3 mm, apex obtuse to acute or acuminate or indistinctly mucronulate; stamens 5. Utricles dark brown to reddish brown, not ribbed, obovoid to subglobose, 1.5–2 mm, thin, almost smooth or irregularly rugose, indehiscent, irregularly dehiscent, or dehiscence regularly circumscissile. Seeds dark reddish brown to dark brown, 0.7–1 mm diam., shiny.