Silky Prairie Clover

Petalostemon villosus Nutt. Gen. 2: S5. 1818
Dalea rillosa Spreng. Syst. 3: 326. 1826. Kuhnistcra villosa Kuntze, Rev. Gen. 192. 1891.
A perennial, with a woody tap-root and caudex, branched at the base, bushy; stems ascending or decumbent, 3-6 dm. high, densely villous; leaves very numerous and crowded, 3-5 cm. long, often with fasciculate ones in their axils; stipules subulate; leaflets 9-17, approximate, oblong or oblanceolate, acute or obtuse, 5-10 mm. long, 2-4 mm. wide, densely villous; spikes terminating the branches, usually subsessile, .sometimes clustered, cylindric, in fruit 8 mm. thick, 2-10 cm. long, dense; bracts lanceolate, caudate-attenuate, longer than the calyces, deciduous, villous; calyx about 3 mm. long, densely villous, 10-ribbed; lobes lanceolate, acute, shorter than the tube; corollas rose-purple, rarely white; blade of the banner cordate, 2 mm. long and as broad, the claw 2.5 mm. long; blades of the other petals elliptic, 2.5 mm. long, the claws 0.5 mm. long; pod obliquely obovate, somewhat lunate, 3 mm. long, villous.
Type locality: Banks of Knife River, near Fort Mandan, North Dakota.
Distribution: Michigan to Missouri. Texas. Montana, and Saskatchewan.

Pere nnial, Herbs, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Plants gland-dotted or with gland-tipped hairs, Stems solid, Stems or young twigs sparsely to densely hairy, Stems silvery, canescent, tomentose, cobwebby, or wooly, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 5-9, Leaflets 10-many, Leaves glandular punctate or gland-dotted, Leaves glabrous or nearly so, Leaves hairy on one or both surfaces, Inflorescences spikes or spike-like, Inflorescence terminal, Bracts conspicuously present, Bracts very small, absent or caducous, Calyx 5-lobed, Calyx hairy, Petals separate, Petals clawed, Petals blue, lavander to purple, or violet, Banner petal narrow or oblanceolate, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel tips obtuse or rounded, not beaked, Fertile stamens 5, Stamens monadelphous, united below, Filaments glabrous, Style terete, Fruit a legume, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit enclosed in calyx, Fruit hairy, Fruit 1-seeded, Seeds reniform, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.