Flora of North America species comparison

erect, dichotomously branched, 5–50 cm, retrorsely to spreading- pubescent throughout.

prostrate to ascending or erect, simple or branched.

stipules ovate-lanceolate, 2–6 mm, apex acuminate, entire;

blade linear to linear-oblanceolate or linear-oblong, 3–25 × 1–2.3 mm, herbaceous, apex ± acute, moderately antrorsely puberulent.

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.

terminal or axillary cymes or flowers solitary;

bracts foliaceous or usually scarious;

involucel bracteoles absent.

present or flowers sessile.

5-merous, cylindric to narrowly lanceolate, with enlarged hypanthium and calyx cylindric to tapering distally, 2.3–3.5 mm, pubescent mostly proximal with hooked or usually straight hairs, sometimes with scattered straight hairs distally;

sepals flecked or solid red-brown, white distally, midrib obscure, linear-lanceolate, 1.5–2 mm, papery, margins white, 0.1–0.2 mm wide, papery, apex terminated by mucro, hood obscure, narrowly rounded, mucro short-conic, ca. 0.1 mm, glabrous;

staminodes filiform, widening proximally, 0.5–0.6 mm;

style 1, cleft in distal 1/10.

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.

terminal and lateral, 15–50+-flowered, often forming large, congested clusters 5–30 mm wide.

broadly ellipsoid to ± globose, 0.5–0.7 mm, smooth, glabrous.

= 7, 8, 9.