Astragalus Beckwithii var. Beckwithii

Stems usually slender, (0.2) 1-3 dm. long; stipules 2-7 mm. long; herbage green or pale green; leaflets commonly suborbicular or broadly oval, truncate or retuse, rarely ovate or obovate, 3-13 (17) mm. long; bracts 2.5-4 mm., bracteoles 0.2 mm. long; calyx nearly always black-strigulose, 7.2-8.2 (9) mm. long, the tube 3.5-5.3 mm. long, 3.2—4 mm. in diameter, the teeth 2.5-3.7 mm. long; pod (1.5) 2-3 cm. long, 7-12 mm. in diameter, the valves nearly always, though sometimes only faintly, mottled.—Collections: 25 (v); representative: Jones 1725 (NY, POM, TEX, UTC, WS, WTU); Eastwood & Howell 9334 (CAS, RSA); Train 3693 (NA, NY); Ripley & Barneby 4763 (CAS, RSA).

Dry hillsides and canyon banks, in alkaline, gravelly soils of various origins but preferring limestone, often among sagebrush or bud-sage (Artemisia arbuscula or A. spinescens), 4200-6450 feet, common and locally abundant in and around the Great Salt Lake Desert in northwestern Utah and northeastern Nevada, south, becoming rarer, to the middle Sevier Valley and Escalante Desert in central and southwestern Utah.—Map No. 106.—Late April to June.

Astragalus Beckwithii (Edwin Griffin Beckwith, 1818-1881, Lieut. U. S. A. in command of Gunnison’s Expedition after the latter’s death in 1853) T. & G. in Pac. R. R. Rep. 2: 120. 1855.—"On the Cedar Mountains, west of Lone Rock, and south of Great Salt Lake... "— Holotypus, collected by Beckwith in 1854, GH!—Tragacantha Beckwithii (T. & G.) O. Kze., Rev. Gen. 943. 1891. Phaca Beckwithii (T. & G.) Piper in Contrib. U. S. Nat. Herb. 11 (Fl. Wash.): 371. 1906. Phacomene Beckwithii (T. & G.) Rydb. in Amer. Jour. Bot. 16: 205. 1929.

The typical variety of the Beckwith milk-vetch is a relatively slender plant with almost round, emarginate or very obtuse leaflets rarely surpassing 12 mm. in length. To the north of Great Salt Lake the plants tend to become coarser in growth, with larger obovate leaflets, and on the Smoke River watershed these probably pass gradually into var. weiserensis. It differs perceptibly from var. purpureus only in having creamy-white petals without any trace of purple.