Flora of North America species comparison

prostrate to erect, dichotomously branched, 3–20 cm, retrorsely to spreading- pubescent throughout.

prostrate to ascending or erect, simple or branched.

stipules ovate-lanceolate, 0.5–7 mm, apex acuminate, entire;

blade elliptic to oblong or ovate, or basal ones spatulate, 2–18 × 1–6 mm, herbaceous to leathery, apex mucronate to short-spine-tipped, moderately antrorsely pubescent.

opposite, distalmost or all sometimes alternate, bases connate or not, sometimes petiolate, stipulate;

stipules ovate or deltate to lanceolate or spatulate, scarious;

blade needlelike or often spatulate to elliptic or suborbiculate, seldom succulent.

diffuse, flowers solitary (paired) in axils of leafy bracts.

terminal or axillary cymes or flowers solitary;

bracts foliaceous or usually scarious;

involucel bracteoles absent.

present or flowers sessile.

5-merous, broadly ovoid, with enlarged hypanthium and calyx tapering distally, 2–2.3 mm, glabrous to strigose;

sepals brownish to yellowish, veins absent, subulate to lanceolate, 1–1.7 mm, leathery to rigid, margins whitish, 0.03–0.1 mm wide, papery, apex terminated by awn, hood obscure, small flange, awn straight to slightly divergent, yellow, 0.3–0.4 mm, scabrous to antrorsely strigose, spinose;

staminodes narrowly triangular, 0.2–0.3 mm;

style 1, cleft in distal 1/8, 0.7–0.9 mm.

bisexual or sometimes unisexual (the plant then dioecious or polygamodioecious);

perianth and androecium perigynous;

hypanthium usually cup-shaped or cylindric or conic to urceolate;

sepals (3–)5, distinct or rarely connate proximally, apex often hooded or awned (awn often subapical);

petals absent;

stamens absent or 1–5, in 1 whorl arising from hypanthium rim;

staminodes absent or 5 (16–19 in Achyronychia);

ovary 1-locular;

styles 1–3, distinct or sometimes connate proximally;

stigmas 2 or 3.

utricles, indehiscent or sometimes opening by 3 or 8–10 valves;

carpophore absent.

1, white to tan or brown to black, ovoid to reniform, not or slightly laterally compressed;

embryo peripheral or central, curved or straight.

ellipsoid to subglobose, 0.5–0.8 mm, essentially smooth, glabrous.

= 7, 8, 9.