Plants annual, glandular-pubescent. Stems ascending to decumbent, much-branched, filiform, glabrous or sometimes glandular-pubescent. Leaves: axillary fascicles absent; basal sometimes in rosettelike whorl, withering early; cauline leaves connate basally, proximal blades linear, 4-8(-12) mm, not fleshy, apex aristate, with hyaline portion of leaf base long-ciliate, cilia occasionally occurring length of leaf (sometimes lacking cilia), distal blades linear to subulate, 1-3 mm toward apex. Pedicels filiform, glandular-pubescent. Flowers axillary, sometimes terminal, 4-merous, very rarely 4- and 5-merous; calyx glandular-pubescent; sepals ovoid to elliptic, sometimes lanceolate, 1.5-2 mm, hyaline margins white, apex somewhat acute, glandular-pubescent, divergent at capsule dehiscence; petals nearly always absent, minute if present; stamens 4(-5). Capsules 1.5-2(-2.5) mm, equaling or barely longer than sepals, dehiscing to base. Seeds brown, obliquely triangular with abaxial groove, 0.3-0.4 mm, smooth, pebbled, or frequently papillose. 2n = 12.

Flowering spring-early summer. Open places, hard-packed soils around buildings, paths, roadsides, sidewalk cracks, grassy hillsides, streambanks; 0-1300 m; introduced; B.C.; Calif., Kans.; Europe.

Historical collections of Sagina apetala are known from Illinois, Louisiana, Maryland, New Jersey, Oregon, and Washington.