Herbs , 3.3-16 cm. Leaf blades linear or very narrowly oblanceolate, 1.8-9.5 cm. Inflorescences: scapes 2.2-12 cm. Flowers: sepals faintly 3-veined, scarious margins narrow or absent; petal claw 1-3 times as long as blade. Heads of achenes 13-42 × 2-3 mm, long-exserted from leaves. Achenes: outer face orbiculate or sometimes square, 0.8-1.2 × 0.6-1 mm, 0.8-1.2 times as high as wide, bordered by prominent ridge; beak 0.6-1.2 mm, 0.6-1.2 times as long as body of achene body, weakly divergent from outer face of achene, heads of achenes thus roughened by projecting achene beaks. 2 n =16.
Flowering late winter-spring (Mar-May). Dry hillsides or canyon bottoms in shrubland; 350-1800 m; Ariz., Calif., Colo., Nev., N.Mex., Tex., Utah; Mexico (Baja California and Sonora).
The Navaho-Ramah used Myosurus cupulatus medicinally both externally and internally as an aid for ant bites or swallowing an ant (D.E. Moerman 1986).
FNA 1997, Wiggins 1964, Kearney and Peebles 1969
Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Dwarf annual, 3.3-16 cm tall. Leaves: Narrowly linear to narrowly linear-spatulate, 1.8-9.5 cm, 1-2 mm wide, faintly 3-5 nerved. Flowers: Scapes 2.2-12 cm long, slender, sepals faintly 3-nerved, scarious margins or absent, about 2.5 mm long, slender spur 1.5 mm long; petals about equaling sepals, narrowly linear with claw 1-3 times as long as blade; spikes 1.5-5 cm long, 2-2.5 mm in diameter at maturity. Fruits: Achenes, outer face orbiculate or sometimes square, 1-1.3 mm long, base of beak surrounded by thickened ridge, light yellow. Ecology: Found on dry hillsides and canyon bottoms in shrubland and in moist ground along streams from 2,500-5,000 ft (762-1524 m); flowers February-April. Notes: The achene is the character that separates the Myosurus, in M. cupulatus the outer face of the achene is bordered by prominent ridge. Ethnobotany: Taken internally or as a lotion for ant bites or the effects of swallowing an ant. Etymology: Myosurus translates to mouse- tail, pertaining to receptacle when mature, while cupulatus means cup-shaped. Synonyms: None Editor: SBuckley, 2010