Slickseed Fuzzybean

Annual, Perennial, Herbs, Vines, twining, climbing, Taproot present, Nodules present, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Stems 1-2 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stems hairs pilose or spreading, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules persistent, Stipules free, Leaves compound, Leaves pinnately 3-foliolate, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Stipels present at base of leaflets, Leaflets 3, Leaves hairy on one or both surfaces, Flowers in axillary clusters or few-floweredracemes, 2-6 flowers, Inflorescences globose heads, capitate or subcapitate, Inflorescence axillary, Bracteoles present, Flowers zygomorphic, Calyx 5-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals pinkish to rose, Banner petal suborbicular, broadly rounded, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel abruptly curved, or spirally coiled, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style hairy, Style hairy on one side only, Fruit a legume, Fruit unilocular, Fruit freely dehiscent, Fruit elongate, straight, Fruit exserted from calyx, Valves twisting or coiling after dehiscence, Fruit glabrous or glabrate, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seed surface smooth, Seed surface wrinkled or rugose, Seeds olive, brown, or black, Seed surface mottled or patchy.

Strophostyles leiosperma, known as slickseed fuzzybean, or smoothseed / small-flower wildbean is a species of herbaceous, vining legume native to the central to western U.S. It occurs west to Colorado and New Mexico, east to Louisiana, south to Mexico, and north to Minnesota. It is most easily distinguished from the other two Strophostyles species by the abundance of small silky hairs on its leaves and pods, and small pea-shaped flowers with a much reduced keel that is largely hidden by the wing petals.

This species is an annual to short-lived perennial. All parts tend to be smaller for S. leiosperma in general than its congeners, and it is a more diminutive plant overall. The leaflets are typically thin and rarely lobed (never deeply lobed). Unlike its congeners, its seeds rarely have a waxy, hairy covering, and it tends to occur in drier sites. Likewise, the specific epithet leiosperma means "smooth seed." It is also the most likely of these species to be capable of self-fertilization.

S. leiosperma flower & unripe pod