Duration: Perennial

Nativity: Native

Lifeform: Forb/Herb

General: Prostrate to decumbent perennial from a tough taproot. Many stems, more or less flexuous, 10-50 cm long, finely white-strigose, stipules broadly deltoid, 1.5-3 mm long, usually as wide.

Leaves: Compound pinnate, 5-10 cm long, ascending, leaflets 9-17, linear, oblong, or lance-oblong; 2-3 mm wide, 8-15 mm long, canescent.

Flowers: Racemes 3-8 cm long, lax, several to many flowered, bracts lanceolate, 2.5-3 mm long, villous without; calyx tube cylindro-campanulate, 3-4 mm long, white-strigose; teeth deltoid, subulate-acuminate, about 2 mm long, corolla white, more or less suffused with greenish yellow, purplish, or maroon, 9-11 mm long; banner obovate, arched but not reflexed; wings slightly shorter than banner and keel, falcate, obtuse at apex; keel broadly lunate, apex blunt, strongly arcuate; flowers March-May.

Fruits: Pods linear, ascending, 1.5-3 cm long, about 3 mm wide, slightly arcuate, flat to slightly sulcate along lower suture, finely white-strigose.

Ecology: Grassy hillsides and in flats, on plains and mesas from 4,500 ft (1372 m) and lower.

Distribution: AZ, NM; south to n MEX.

Notes: Astragalus is the most species-rich genus in the world and is especially speciose in the southwest. There are over 200 taxa in Arizona alone. Many species are notoriously difficult so its best to voucher to be sure. This species is fairly distinct as a prostrate-decumbent perennial with radiating stems and silvery herbage with copious, appressed, stiff hairs which are attached at the middle; linear leaflets; dingy-purple flowers; and 2-celled pods which are compressed, appearing linear.

Ethnobotany: Astragalus spp. used medicinally for chest cough, colds.

Etymology: Astragalus is from Greek astragalos meaning ankle bone and is an early name applied to the genus because of the shape of the seeds, arizonicus is named for Arizona.

Synonyms: None

Editor: SBuckley 2010, FSCoburn 2014