Proc. Amer. Acad. Arts 17: 362. 1882.
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. 2n=16.
Phenology: Flowering spring (Mar–May).
Habitat: Vernal pools and alkalai flats
Elevation: 10-1600 m
Of conservation concern.
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.