Plant: annual; stem ascending to erect, 4-25 cm Leaves: generally alternate, generally 0.5-4 cm, ± linear, strigose to sharp-bristled INFLORESCENCE: cymes; pedicels in fruit 2.5-4 mm, generally free from nutlets, generally recurved 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: Fruit: nutlets 4, slightly to moderately recurved ± throughout, 2.5-4.5 mm, oblanceolate to narrowly obovate; margin teeth fused at base, width at base ± = length, marginal prickles hooked at tip, not barbed Misc: Washes, roadsides in creosote-bush scrub, Joshua-tree woodland; 150-1500 m.; Mar-May References: J.C. Hickman. The Jepson Manual. Kearney & Peebles. Arizona Flora. W.B. McDougal. Seed plants of Northern Arizona. ASU specimens.