Flora of North America species comparison

erect, usually much-branched, 4–30 cm, retrorsely to spreading-pubescent mostly on 1 side.

prostrate to ascending or erect, simple or branched.

stipules subulate to lanceolate, 0.5–4.5 mm, apex acuminate, sometimes fimbriate;

blade usually dotted or blotched, oblanceolate to elliptic or obovate, 2–25 × 0.5–7(–10) mm, herbaceous to leathery, apex subobtuse to acute or cuspidate, glabrous or occasionally with very few scattered trichomes along midrib.

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, short-cylindric, with enlarged hypanthium and calyx ± cylindric, 1.1–1.6 mm, glabrous or with few scattered hairs;

sepals greenish to brownish, veins absent, linear-oblong, 1–1.2 mm, leathery to rigid, margins white to translucent, 0.05–0.1 mm wide, scarious, apex terminated by mucro, hood narrowly rounded, mucro short-conic, 0.05–0.3 mm, ± minutely scabrous;

staminodes absent;

styles 2, 0.07–0.6(–0.7) 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.

terminal, 25–70+-flowered, branched, loose to compact, forming clusters 3–10 mm wide.

obovoid to obconic, 0.7–1 mm, minutely papillate.

= 7, 8, 9.

= 32, 36.