Mollugo verticillata 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 annual, repeatedly forked, forming mats to 4 dm wide; lvs in whorls of 3–8, narrowly to broadly oblanceolate, 1–3 cm, tapering to a short petiolar base; fls 2–5 from each node, on pedicels 5–15 mm, pale green or white, 4–5 mm wide; stamens 3 or 4; fr ovoid, 3 mm; seeds numerous, arcuate-ridged; 2n=64. Apparently native to tropical Amer., but now a common weed in moist soil and dunes nearly throughout temperate N. Amer. June–Sept.