1. Myosurus minimus Linnaeus, Sp. Pl. 1: 284. 1753.
Myosurus lepturus Greene; M. lepturus var. filiformis (Greene) Greene; M. minimus subsp. major (Greene) G.R. Campbell; M. minimus var. filiformis Greene; M. minimus var. major (Greene) K.C. Davis
Herbs , 4-16.5 cm. Leaf blades narrowly oblanceolate or linear, 2.2-11.5 cm. Inflorescences: scape 1.8-12.8 cm. Flowers: sepals faintly or distinctly 3-5-veined, scarious margins narrow or absent; petal claw 1-2 times as long as blade. Heads of achenes 16-50 × 1-3 mm, exserted beyond leaves. Achenes: outer face narrowly rhombic to elliptic or oblong, 0.8-1.4 × 0.2-0.6 mm, 1.5-5 times as high as wide, not bordered; beak 0.05-0.4 mm, 0.05-0.3 as long as body of achene, parallel to outer face of achene, heads of achenes thus appearing smooth. 2 n =16.
Flowering spring (Mar-Jun). Wet fields, vernal pools, banks of streams and lakes; 0-3000 m; Alta., B.C., Man., Ont., Sask.; Ala., Ariz., Ark., Calif., Colo., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Minn., Miss., Mo., Mont., Nebr., N.Mex., N.C., N.Dak., Okla., Oreg., Pa., S.C., S.Dak., Tenn., Tex., Utah, Va., Wash., Wyo.; Mexico (Baja California); Europe; swAsia; nAfrica.
Plants of Myosurus minimus from a few sites in coastal southern California, northern Baja California, and immediately west of Riley, Oregon, sometimes have short scapes, so that the heads of achenes are immersed in the leaves. These plants, which have been called M . minimus subsp. apus (Greene) G. R. Campbell, M . minimus var. apus Greene, or M . clavicaulis M. E. Peck are indistinguishable from some recombinant lines found in M . minimus × sessilis hybrid swarms (see discussion under M . sessilis ), but they occur outside the current range of M . sessilis . D. E. Stone (1959) has suggested that they resulted from past hybridization between the two species, perhaps at a time when M . sessilis had a wider range than it does now.
The Navaho-Ramah used Myosurus minimus medicinally to apply to antbites (D. E. Moerman 1986).