Plant: annual; stem prostrate to decumbent, 2-25 cm Leaves: generally alternate, generally 0.5-4 cm, ± linear, strigose to sharp-bristled INFLORESCENCE: cymes, pedicel in fruit ascending, 1.3-2.5 mm Flowers: sepals generally < fruit, upper 2 in fruit generally > others; corolla 0.8-3 mm, white; style attached to receptacle, unbranched, generally persistent, stigma 1, head-like Fruit: nutlets 4, straight, 1.1-3.3 mm, oblanceolate; margins erect to incurved, ± entire, all in a flower ± equal in width, bristled only above ± middle, marginal prickles hooked at tip, not barbed Misc: Disturbed sites, roadsides in many communities; 90-2100 m.; Mar-May