Flora of North America species comparison

often forming dense mats, 5–30+ cm, often obscured by stipules and dense pubescence.

prostrate to ascending or erect, simple or branched.

stipules 1–8 mm, often nearly as long as leaves, lobes acuminate;

blade 2-grooved, 5–13 mm, apex finely spinose, glabrous.

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.

densely woolly, hairs 0.5–1.5 mm;

sepals 5, margins fimbriate, awn 1.5–4 mm;

staminodes white, 0.3–0.5 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.

1.4–1.6 mm.

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

embryo peripheral or central, curved or straight.

apex apiculate.

= 7, 8, 9.