Flora of North America species comparison

erect, branched, usually (0.3–)0.5–1.5(–3) m;

proximal branches often ascending.

erect, green, branched, 0.3–1 m.

long-petiolate;

blade obovate or rhombic-obovate to elliptic proximally, sometimes lanceolate distally, 1.5–7 × 1–3.5 cm, base broadly to narrowly cuneate, margins entire, plane, apex subobtuse to acute, usually with terminal mucro.

petiole of proximal leaves equaling or longer than blade, becoming shorter distally;

blade rhombic-ovate or ovate to elliptic, 3–12 × 2–8 cm, base broadly cuneate, margins entire, apex slightly acuminate to obtuse and faintly emarginate, mucronate.

of pistillate flowers with long-excurrent midrib, 4–6 mm, longer than tepals, apex acuminate or mucronulate; of staminate flowers, 4 mm, equaling or longer than outer tepals, apex long-acuminate.

lanceolate, shorter than 2 mm, shorter than tepals, apex spinescent.

terminal, linear spikes to panicles, usually drooping, occasionally erect, especially when young, with few axillary clusters, uninterrupted or interrupted in proximal part of plant.

terminal panicles and axillary spikes;

panicles erect or often drooping, green, dense, branched, leafless at least distally.

tepals 5, unequal, 2–4 mm, apex acute;

inner tepals with prominent midrib excurrent as rigid spine, apex long-acuminate or mucronulate;

stamens 5.

usually clustered at tips of inflorescence branches, sometimes gathered in proximal glomerules (as in A. spinosus);

tepals 5, equal or subequal;

stamens 5.

tepals 1.7–3.8 mm, apex acuminate, mucronulate;

style branches spreading;

stigmas 2(–3).

tepals 5, oblong-spatulate to oblong, not clawed, 1.5–2 mm, apex acute, often very shortly mucronate;

style branches strongly spreading, shorter than body of fruit;

stigmas 3.

dark reddish brown to brown, 1–1.2 mm diam., shiny.

dark reddish brown to black, subglobose or lenticular, 0.8–1 mm diam., shiny, smooth.

tan to brown, occasionally reddish brown, obovoid to subglobose, 1.5–2 mm, shorter than tepals, at maturity walls thin, almost smooth or indistinctly rugose.

ovoid or subglobose, 1.5–2 mm, slightly shorter than tepals, smooth to irregularly wrinkled, dehiscence regularly circumscissile.

= 64.