Plants glabrous or densely pubescent or glandular. Stems often branched proximally, 5-35 cm. Leaf blades usually flat, 0.3-1.5(-2) cm, usually not channeled abaxially. Pedicels erect to ascen-ding, spreading or sometimes reflexed in fruit, sometimes secund. Flowers: sepals 3-4 mm; petals ovate, 3- 8 times as long as sepals in flower, apex obtuse; stamens usually 10. Capsule valves 3.5-6 mm. Seeds winged, lenticular, 0.9-1 mm wide, surface minutely roughened or low-tuberculate (50×), with marginal ring of tan, club-shaped papillae; wings light brown to brownish black, 0.2-0.3 mm wide. 2n = 18 (Europe). Flowering spring-early summer. Sandy roadsides, disturbed areas; 10-100 m; introduced; Md., Mass., N.J.; Europe. Spergula morisonii was first reported for North America from New Jersey in 1966; the earliest collections date from 1917 (D. B. Snyder 1987). It should be expected elsewhere in the flora area; the collections from Maryland and Massachusetts date from 2002 and 2000 respectively, with the Maryland population described as including 'thousands of plants' (B. W. Steury 2004).
Much like no. 1 [Spergula arvensis L.], but the lvs not channelled and the seeds compressed, with a brownish, striate wing barely or scarcely half as wide as the body; pet ovate, contiguous or slightly overlapping, obtuse; 2n=18. European weed, occasionally intr. in our coastal states and fully established at least in s. N.J.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.