Flora of North America species comparison

prostrate to erect, simple or branched.

opposite or sometimes appearing whorled, bases connate or not, sometimes petiolate or often sessile, stipulate;

stipules ovate or deltate to lanceolate or bristlelike, scarious;

blade subulate or subtriangular to linear and threadlike or spatulate to ovate or orbiculate, seldom succulent.

terminal or axillary cymes, or flowers solitary;

bracts scarious or absent;

involucel bracteoles absent.

present or flowers sessile.

bisexual or rarely unisexual;

perianth and androecium hypogynous or perigynous;

hypanthium absent or dish- or cup-shaped;

sepals 5, distinct or sometimes connate proximally, hooded (Drymaria, Polycarpon) or not, awned (Polycarpon) or not;

petals absent or (3–)5, blade clawed (Drymaria) or not, auricles absent, coronal appendages absent, blade apex entire, erose, or 2(–4)-fid, sometimes emarginate;

stamens (1–)3–5(–10), in 1 or 2 whorls, usually arising from base of ovary or from rim of hypanthium (Spergula, Spergularia);

staminodes absent;

ovary 1-locular;

styles 1 or 3, occasionally 2 or 5, distinct or sometimes connate proximally;

stigmas 3, occasionally 2 or 5.

capsules, opening by 3 or 5, occasionally 4 valves;

carpophore sometimes present.

3–150+, whitish or tan to often brown or black, ± triangular, pyriform, or reniform to circular, subglobose or laterally compressed to angular (Polycarpon);

embryo peripheral, curved or rarely annular to spirally curved (Spergula).

= [7], 8, 9, (11), 12.