Flora of North America species comparison

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

proximal branches often ascending.

prostrate or weakly ascending, erect when young, branched mostly from base, 0.1–0.6 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 nearly 1/2 as long as blade;

blade broadly elliptic, obovate, orbiculate, or oblanceolate, (0.5–)1–3(–4.5) × 0.3–2(–2.5) cm, base cuneate, margins entire, plane to undulate, apex broadly rounded or emarginate.

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.

of pistillate flowers keeled (only A. scleropoides and A. crassipes have keeled bracts), deltate, 0.5–0.9 mm.

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

axillary clusters borne from base to apex, axes much thickened, appearing inflated, becoming indurate at maturity (only in A. scleropoides and A. crassipes).

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

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

stamens 5.

intermixed with pistillate;

tepals 5, membranaceous;

stamens 3(–5).

tepals 1.7–3.8 mm, apex acuminate, mucronulate;

style branches spreading;

stigmas 2(–3).

tepals (4–)5, narrowly spatulate, clawed, with small expanded blade, equal or subequal, 2–3 mm, apex rounded and apiculate;

claws becoming indurate and scarious at maturity;

style branches spreading;

stigmas usually 2(–3), almost sessile.

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

dark brownish or reddish black to black, compressed-ovoid to broadly lenticular, 1–1.4 mm diam., shiny.

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.

obovoid to compressed-obovoid, 1.4–2 mm, shorter than tepals, prominently muricate (especially in distal 1/2), indehiscent.