Flora of North America species comparison

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

proximal branches often ascending.

ascending to prostrate, erect when young, or main stems ± erect, branched proximally, 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 equaling or 1/2 as long as blade;

blade elliptic, oblanceolate to lanceolate, (0.5–)1–3(–3.5) × 0.3–2 cm, base tapering, margins entire, plane to slightly 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), ovate-triangular, minute.

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 top, axes thickened and 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.

tepals 1.7–3.8 mm, apex acuminate, mucronulate;

style branches spreading;

stigmas 2(–3).

tepals 5, narrowly spatulate, slightly clawed, with expanded blade, equal or subequal, (1.2–)1.5–2.5 mm, apex acute to apiculate;

claws indurate at maturity;

style branches spreading;

stigmas 2–3.

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

dark brownish black to black, compressed-ovoid to broadly lenticular, 0.9–1.1 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.

orbicular to compressed-obovoid, 1.1–1.5 mm, shorter than tepals, smooth to tuberculate in distal 1/2, dehiscence regularly circumscissile.