Plants annual or perennial; rhizomes, when present, without tuber-like thickenings.
Stems erect to prostrate.
Leaves opposite, linear to ovate; petioles present (basal leaves) or 0; stipules 0.
Inflorescences terminal or axillary cymes, or flowers solitary; bracts present; usually pedicellate.
Flowers bisexual; sepals (4)5, free, glabrous to glandular-hairy; petals (0)1–5, white, tips 2-lobed > 20% length or often divided nearly to base; stamens (1)5 or 10, borne on nectariferous disk, staminodes 0; styles 3(4–5).
Fruits capsules, ovoid or spherical to cylindric-oblong, opening by 6(8, 10) ascending to recurved valves.
Seeds 3–20+, globose to compressed-ellipsoid, 0.5–1.3 mm, yellowish to dark brown, papillate or tuberculate, rarely smooth.
Worldwide, especially in north temperate regions. ~190 species; 11 species treated in Flora.
The hybrid S. borealis × S. longifolia has been collected once in Oregon along a stream in Klamath County in 1928. As expected, this sterile hybrid exhibits some features of both parents; the combination of lanceolate to lance-linear leaves, a lateral inflorescence, the lowermost flowers subtended by large, leafy bracts and all others subtended by much reduced scarious bracts, and an absence of capsules can be used to recognize this plant. Two additional species closely resembling, and related to, Stellaria media are to be expected in Oregon. Stellaria neglecta (greater chickweed) has been collected in California and from Whidbey Island, Washington in 2004. It resembles a large S. media plant and is most consistently distinguished by having sepals 5–6 mm and seeds with conical, rather than rounded, tubercles, especially on the marginal face. Stellaria pallida (lesser chickweed) is also known from California and from several sites in Washington that have been made since 2000. This species resembles a smaller S. media with apetalous flowers with sepals 2–3 mm and seeds that are 0.7–0.8 mm and yellow-brown.
as described under Stellaria
Plants annual, winter annual, or perennial. Taproots usually slender, perennial taxa often rhizomatous, rooting at nodes. Stems prostrate to ascending or erect, simple or branched, terete or 4-angled. Leaves 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. Inflorescences 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. Pedicels erect, sometimes reflexed in fruit, glabrous or pubescent, not glandular. Flowers 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 3- 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 (30×). Capsules globose to conic, opening by 3 or 6, occasionally 4, 8, or 10 ascending to recurved valves; carpophore present or absent. Seeds (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. x = 10, 11, 12, 13, 15.