1. Myosurus minimus L. (mousetail)

Pl. 516 n, o; Map 2366

Plants annuals, taprooted. Stems absent. Leaves several to numerous in a basal rosette, lacking well-defined petioles, 2.0–11.5 cm long. Leaf blades simple, unlobed, linear to very narrowly oblanceolate, somewhat flattened but relatively thick, the margins entire, the surfaces glabrous. Inflorescences of solitary flowers at the tips of naked stalks, these erect or ascending, as long as or longer than the leaves. Flowers actinomorphic, perfect. Sepals (3–)5(–8), 1.5–4.0 mm long, green or pinkish- to reddish-tinged, plane, not persistent at fruiting, each with a slender spur 0.7–3.0 mm long, this appressed-descending along the tip of the flower stalk. Petals rarely absent, usually (1–)5, 1.0–2.5 mm long, slender, tapered to a stalklike base, more or less plane, white, not persistent at fruiting. Stamens not showy, the anthers yellow. Staminodes absent. Pistils numerous (to 400) in a dense spiral, each with 1 ovule. Style present. Fruits dense cylindric-tapered aggregates (1–3 mm wide) of achenes, these narrowly rhombic to elliptic or oblong in profile, 3-angled in cross-section; the body 4–5 mm long, the inner angle extended as a minute, appressed-ascending beak, the outer wall thick, not noticeably veined. Receptacle becoming elongated to 15–50 mm at fruiting. 2n=16. March–May.

Scattered nearly throughout the state (nearly throughout the U.S.; Canada, Mexico, Europe, Asia, Africa). Banks of streams and rivers, margins of ponds, lakes, and sinkhole ponds, marshes, swamps, fens, and openings of bottomland forests; also crop fields, fallow fields, old fields, pastures, ditches, gardens, railroads, roadsides, and moist disturbed areas.

Steyermark (1963) noted that the petite plants are winter annuals with seeds that sprout in the fall and that persist through the winter as basal rosettes.