Halfmoon Milkvetch

Phaca allochroa (A. Gray) Rydb. Fl. Rocky Mts. 487, 1063 1917.
Astragalus allochrous A. Gray, Proc. Am. Acad. 13: 366. 1878.
Perennial, with a caudex; stems eitct, 3-5 dm. high, sparingly strigose; leaves strongly ascending, about 1 dm. long; stipules deltoid, acuminate, pubescent, scarious, 4-5 mm. long; rachis strigose; leaflets 11-19, oblong to obovate, rounded to retuse at the apex, strigose on both sides; peduncles 5-7 cm. long; racemes 310 cm. long, 8-15-flowered; bracts lance-subulate, 2-3 mm. long; calyx strigose, the tube campanulate, 3 mm. long, the teeth subulate, 1.5 mm. long; wings shorter than the banner, the blade longer than the claw, oblong; keel-petals strongly incurved, the blade obliquely obovate, lounded at the apex; pod sessile, strigulose, about 3 cm. long and 1.5 cm. wide, acute, the upper suture nearly stiaight; seeds obliquely reniform, brown,
2 mm. long.
Type locality: Near Wickenburg, Arizona. Distribution: Arizona and southern New Mexico.

Annual, Herbs, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems less than 1 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrate, Stems or young twigs sparsely to densely hairy, Leaves alternate, Leaves pe tiolate, 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, Inflorescences racemes, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Petals separate, Corolla papilionaceous, Petals clawed, Petals white, Petals pinkish to rose, 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 stipitate, Fruit unilocular, Fruit humistrate, lying on the ground, Fruit tardily or weakly dehiscent, Fruit oblong or ellipsoidal, Fruit exserted from calyx, Fruit inflated or turgid, Fruit glabrous or glabrate, Fruit 11-many seeded, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.