Cobblestone Milkvetch

Xylophacos nudisiliquus (A. Nelson) Rydb. Bull. Torrey Club 52: 368. 1925.
Astragalus nudisiliquus A. Nelson, Bot. Gaz. 54: 410. 1912.
A cespitose perennial, with a much branched eaudex; stems very short, less than 1.5 dm. long; leaves 3-6 dm. long, spreading ; stipules lanceolate, 3-5 mm. long; leaflets 9-19, obovate, more or less densely white-villous, 5-10 mm. long, rounded at the apex; peduncles 2-4 cm. long; racemes 5-8-flowered ; bracts subulate, 3-5 mm. long; calyx whitevillous, the tube 9-10 mm. long, about 3 mm. broad, the teeth subulate, 2 mm. long; corolla ochroleucous or slightly tinged with purple; banner obovate, retuse; wings slightly shorter, the blade linear; keel-petals slightly shorter than the wings, the blade short and broad, strongly arched and rounded at the apex; pod 2-2.5 cm. long, 1 cm. thick, and 5 mm. wide, slightly sulcate on the upper suture, rather sparingly villous, strongly incurved above the middle; seeds obliquely reniform, 3 mm. long, 2 mm. broad.
Type locality: King Hill. Elmore County, Idaho. Distribution: Type locality and Malheur County. Oregon.

Perennial, Herbs, Stems woody bel ow, or from woody crown or caudex, Taproot present, Nodules present, Stems or branches arching, spreading or decumbent, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stems silvery, canescent, tomentose, cobwebby, or wooly, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules membranous or chartaceous, Stipules persistent, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 10-many, Leaves hairy on one or both surfaces, Flowers in axillary clusters or few-floweredracemes, 2-6 flowers, Inflorescences racemes, Inflorescences globose heads, capitate or subcapitate, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Petals separate, Corolla papilionaceous, Petals clawed, Petals pinkish to rose, Petals blue, lavander to purple, or violet, Banner petal narrow or oblanceolate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel petals auriculate, spurred, or gibbous, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style persistent in fruit, Fruit a legume, Fruit unilocular, Fruit humistrate, lying on the ground, Fruit tardily or weakly dehiscent, Fruit oblong or ellipsoidal, Fruit strongly curved, falcate, bent, or lunate, Fruit fleshy, Fruit coriaceous or becoming woody, Fruit exserted from calyx, Fruit beaked, Fruit glabrous or glabrate, Fruit hairy, Fruit 11-many seeded, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.