Sagina procumbens L.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Glabrous, branching perennial, prostrate to ascending, the stems 2–10 cm; lvs linear-subulate, 3–10(–15) mm, to about 1 mm wide, mucronate or shortly aristate, sometimes minutely ciliate, frequently subtending short shoots or lf-fascicles; fls solitary or few at the tips of the stem and branches, or some of them on axillary pedicels, often nodding after anthesis, but finally erect; sep 4(5), 2–2.5 mm, spreading after maturity; pet shorter than the sep, or none; stamens as many as the sep; fr about equaling the sep, commonly 2–3 mm; seeds 0.3–0.5 mm, flattened, obliquely triangular, sulcate along the 2 dorsal angles, very finely roughened; 2n=22. Moist soil and rocky places, often a weed in paths or pavements; circumboreal, s. in Amer. to Md., Mich., and Kans. Summer.