Giant Milkvetch

Astragalus giganteus S. Wats. Proc. Am. Acad. 17: 370. 1882
Astragalus yaquianus S. Wats. Proc. Am. Acad. 23: 270. 1888.
Astragalus texanus Sheldon. Minn. Bot. Stud. 1: 65. 1894.
Astragalus giganteus yaquianus M. E. Jones, Rev. Astrag. 234 (as to type). 1923.
A perennial, with a rootstock; stem 3-15 dm. high, flexuose, silky, in age with brownish, tangled, appressed hairs; leaves short-petioled, 1.5-2 dm. long, ascending; stipules deltoid, herbaceous, 5-8 mm. long; leaflets 21-31, oval or elliptic, acute or obtuse, 1.5-3.5 cm. long, silky-tomentose with loosely appressed, tangled hairs; peduncles 1-2 dm. long, strict; racemes dense, 5-15 cm. long; bracts lance-subulate, 5 mm. long; calyx silky-tomentose, the tube 7-8 mm. long, 3 mm. broad, the teeth subulate, 3 mm. long; corolla ochroleucous, about 2 cm. long; banner narrowly obovate, nearly straight, slightly retuse at the apex; wings shorter, narrow, the blade linear-oblong, with a large reflexed basal auricle; keel-petals much shorter, about 1.5 cm. long, the blade strongly lunate, rounded at the apex, with a large broad auricle; pod oblong-ovoid, abruptly acuminate, glabrous, 15-20 mm. long, 8 mm. thick, and 6 mm. wide, somewhat reticulate, slightly sulcate on both sutures.
Type locality: Fort Davis, Western Texas.
Distribution: New Mexico, Chihuahua, and western Texas.

Perennial, Herbs, Stems woody below, or from woody crown or caudex, Taproot present, Nodules present, Stems erect or ascending, Stems less than 1 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stem hairs hispid to villous, 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, Inflorescences racemes, Inflorescence axillary, Bracts very small, absent or caducous , Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Petals separate, Corolla papilionaceous, Petals clawed, Petals ochroleucous, cream colored, Petals orange or yellow, 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 freely dehiscent, Fruit oblong or ellipsoidal, Fruit or valves persistent on stem, Fruit exserted from calyx, Fruit inflated or turgid, Fruit beaked, Fruit glabrous or glabrate, Fruit 11-many seeded, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.