Herbs , 0.8-2.5 cm. Leaf blades linear or nearly so, 1.6-7.4 cm. Inflorescences: scapes 0-0.2 cm. Flowers: sepals indistinctly 3-veined, scarious margins broad; petal claw about as long as blade. Heads of achenes 8-25 × 2-4 mm, immersed among leaves. Achenes: outer face narrowly rhombic or occasionally narrowly oblong, 1.2-2 × 0.4-0.8 mm, 2-4.5 times as high as wide, not bordered; beak 0.8-1.8 mm, 0.6-1.1 times as long as body of achene, diverging from outer face of achene, heads of achenes thus strongly roughened by projecting achene beaks. 2 n =16.

Flowering spring (Mar-May). Vernal pools and alkalai flats; of conservation concern; 10-1600 m; Calif., Oreg.

Myosurus sessilis often grows with M . minimus , and hybrids between the two species are common. Because the plants mostly set seed by self-pollination, these hybrids often give rise to inbred lines showing the characteristics of the two parents in various combinations (D. E. Stone 1959). The names M . alopecuroides Greene and M . sessilis subsp. alopecuroides (Greene) D. E. Stone are based on the hybrid M . minimus × sessilis or on inbred lines descended from this hybrid.