Flora of North America species comparison

usually slender, perennial taxa often rhizomatous, rooting at nodes.

prostrate, branched, 4-sided, 3–23 cm, internodes equaling or longer than leaves, glabrous, rarely pilose.

prostrate to ascending or erect, simple or branched, terete or 4-angled.

sessile or short-petiolate;

blade broadly ovate to elliptic, 0.2–1.2 cm × 0.9–7 mm, base round or cuneate, margins entire, apex acute, shiny, glabrous or ciliate near base.

sometimes connate basally into sheath, often sessile;

blade 1-veined, linear or lanceolate to ovate or deltate, succulent (S. crassifolia [gemmae], S. fontinalis, S. humifusa, and S. irrigua) or not, apex acute or obtuse.

with flowers solitary, axillary;

bracts absent.

terminal, open cymes, rarely axillary (S. alsine, S. americana) or umbellate (S. umbellata), or terminal or axillary solitary flowers;

bracts paired (1 in S. dicranoides), foliaceous, scarious and reduced, or absent.

spreading, 3–12 mm, glabrous.

erect, sometimes reflexed in fruit, glabrous or pubescent, not glandular.

1.5–2 mm diam.;

sepals 4–5, veins obscure, midrib sometimes apparent, ± ovate, 1.5–3.5 mm, margins narrow, scarious, apex ± obtuse, glabrous;

petals absent;

stamens 10 or fewer;

styles 3(–4), curled, shorter than 0.5 mm.

usually bisexual (S. dicranoides unisexual);

perianth and androecium hypogynous or weakly perigynous;

hypanthium cup- or disc-shaped;

sepals (4–)5, distinct, green, occasionally purple tinged (S. irrigua) or red proximally (S. pallida), lanceolate to ovate-triangular, 2–12 mm, herbaceous (rarely coriaceous), margins often white, scarious, apex acute, acuminate, or obtuse, not hooded;

petals (1–)5 or absent, white (sometimes translucent in S. borealis), not clawed, blade apex 2-fid usually for 2/3–4/5 its length (S. holostea occasionally laciniate);

nectaries at base of filaments opposite sepals usually present, disc sometimes prominent;

stamens (1–)5 or 10 or absent, arising from nectariferous disc (prominent in S. dicranoides and S. irrigua) at ovary base;

filaments distinct;

staminodes absent;

styles [2–]3(–5), capitate to clavate, 0.2–7 mm, glabrous proximally;

stigmas [2–]3(–5), terminal or subterminal, papillate (30x).

green to pale straw colored, translucent, globose to broadly ovoid, 2.3–3.5 mm, 1.9–2 times as long as sepals, apex obtuse, opening by 6 valves;

carpophore absent.

globose to conic, opening by 3 or 6, occasionally 4, 8, or 10 ascending to recurved valves;

carpophore present or absent.

grayish black, broadly elliptic, 0.5–0.7 mm diam., finely reticulate.

(1–)3–20+, yellow-brown to dark brown, globose to ellipsoid, laterally compressed, rarely shiny, papillate or rugose, rarely smooth, marginal wing absent, appendage absent.

= 10, 11, 12, 13, 15.

= 26, 52, ca. 65, ca. 78.