Slimleaf Bean

Perennial, Herbs, Taproot present, Nodules present, Stems or branches arching, spreading or decumbent, Stems less than 1 m tall, Stems 1-2 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrate, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules green, triangulate to lanceolate or foliaceous, 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 glabrous or nearly so, Flowers in axillary clusters or few-floweredracemes, 2-6 flowers, Inflorescences racemes, Inflorescence axillary, Bracts conspicuously present, Bracteoles present, Flowers zygomorphic, Calyx 5-lobed, Calyx 4-lobed, Calyx glabrous, Petals sep arate, Corolla papilionaceous, Petals pinkish to rose, Petals blue, lavander to purple, or violet, Banner petal suborbicular, broadly rounded, Banner petal auriculate, Wing petals narrow, oblanceolate to oblong, Keel abruptly curved, or spirally coiled, Keel tips obtuse or rounded, not beaked, Keel petals fused on sides or at tip, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style spirally coiled, Style hairy, Fruit a legume, Fruit unilocular, Fruit freely dehiscent, Fruit oblong or ellipsoidal, Fruit strongly curved, falcate, bent, or lunate, Fruit exserted from calyx, Fruit explosively or elastically dehiscent, Valves twisting or coiling after dehiscence, Fruit beaked, Fruit glabrous or glabrate, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seed surface wrinkled or rugose, Seeds olive, brown, or black.

Phaseolus angustissimus (common name slimleaf bean) is a perennial, herbaceous vine of the Fabaceae (legume) family, native to the American Southwest (particularly, Arizona, New Mexico, and Texas), as well as northern Sonora, Mexico. It is a close relative of the cultivated tepary bean (P. acutifolius), also native to the same region.