Plants annual or short-lived perennial, delicate, 4-25 cm, stipi-tate-glandular in inflorescence. Taproots slender to ± stout. Stems erect to ascending or prostrate, usually much-branched proximally; main stem 0.3-0.5 mm diam. proximally. Leaves: stipules conspicuous, shiny white, lanceolate, 3.5-5 mm, apex long-acuminate; blade filiform to linear, 0.4-1.5 cm, scarcely fleshy, apex apiculate to spine-tipped; axillary leaves 2-4+ per cluster. Cymes simple to 3+-compound or flowers solitary and axillary. Pedicels ascending to reflexed. Flowers: sepals connate 0.5-0.7 mm proximally, lobes often 3-veined, lanceolate, (2-)2.5-3.2 mm, to 4 mm in fruit, margins 0.1-0.3 mm wide, apex obtuse to acute; petals pink, obovate to ovate, 0.9-1 times as long as sepals; stamens 6-10; styles 0.6-0.8 mm. Capsules greenish to tan, 3.5-5 mm, 1-1.2 times as long as sepals. Seeds red-brown to dark brown, with submarginal groove, broadly ovate or ± truncate, angular at broad end, plump, 0.4-0.6 mm, sculpturing of parallel, wavy lines, margins with peglike papillae (30×); wing absent. 2n = 18, 27, 36, 54 (all Europe). Flowering spring-fall. Open forests, gravelly glades, meadows, mud flats, roadsides, disturbed places; 0-2400 m; introduced; St. Pierre and Miquelon; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., P.E.I., Que., Yukon; Alaska, Calif., Colo., Conn., Del., D.C., Idaho, Ill., Ind., Ky., Maine, Md., Mass., Mich., Minn., Mont., Nev., N.H., N.J., N.Mex., N.Y., Ohio, Oreg., Pa., R.I., Utah, Vt., Va., Wash., Wis., Wyo.; Europe; Asia; introduced in South America, Australia. Spergularia rubra was collected in 1901 on ballast in Alabama (Mohr, DS), the only record in the southeastern United States. It is the most widely distributed Spergularia species found outside of saline areas in the flora and has been in North America since at least the 1860s.
Annual or short-lived perennial herb with a taproot 4 - 30 cm tall Stem: prostrate to ascending, unbranched or much-branched, sometimes sparsely glandular-hairy above. Leaves: opposite, stalkless, 0.4 - 3.5 cm long, 0.4 - 1.2 mm wide, thread-like to linear, often bristle-tipped, one-veined, not very fleshy. Stipules conspicuous, two per node, fused at the base, shiny white, 2.5 - 5 mm long, lance-shaped with a long-pointed tip, scarious (dry, thin, and membranous). Inflorescence: an axillary, solitary flower or a terminal, widely branched cluster (cyme) of flowers, subtended by bracts. Flowers: pink. Stamens six to ten. Styles three. Sepals: five, fused at the base, green, 2.5 - 3.2 mm long, to 5 mm in fruit, lance-shaped, often three-veined, scarious-margined (dry, thin, and membranous). Petals: five, pink, egg-shaped to reverse egg-shaped. Fruit: a dehiscent capsule, opening by three spreading valves, greenish to tan, 3.5 - 5 mm long, egg-shaped. Seeds many, reddish brown to dark brown, about 0.5 mm long, broadly egg-shaped, angular at wide end, plump, bumpy.
Similar species: The similar Spergularia marina differs by having less stamens per flower (two to five) and fleshy leaves. Spergularia media is also similar but has fleshy leaves and winged seeds.
Flowering: May to September
Habitat and ecology: Introduced from Europe. Very rare in waste places. Has been found in sandy nursery rows, in a wooden planter, and on the shore of a lake.
Occurence in the Chicago region: non-native
Etymology: Spergularia refers to the genus Spergula (which comes from the Latin word spargo, meaning sow or scatter, referring to the discharge of seeds). The Latin -aria means "pertaining to." Rubra means red.
Simple or much-branched annual or short-lived perennial, prostrate or ascending, 5-30 cm, glabrous or sparsely glandular-hairy above; lvs linear-filiform, mucronate, scarcely fleshy, 3.5-35 נ0.4-1.2 mm; stipules triangular-acuminate, 2.5-5 mm; sep 3.5-5 mm, lanceolate; pet consistently pink, shorter than the sep; stamens (6-)10; fr 3.5-5 mm; seed 0.4-0.6 mm, papillate, wingless; 2n=36, 54. Native of Europe, intr. as a weed in sandy or gravelly soil from Nf. to Mich., Wis., and B.C., s. to Md., Ala., N.M., and Calif. May-Sept. (Tissa r.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.