Astragalus lentiginosus var. vitreus

Perennial, with numerous decumbent and ascending stems, the herbage dark green, the leaflets very thinly strigulose beneath with subappressed hairs up to 0.35-0.5 mm. long, glabrous above, commonly ciliate; leaves 4.5-10 cm. long, with (7) 13-19 obovate-cuneate or oblong-obovate, obtuse or commonly truncate-emarginate, rather thick-textured, flat leaflets (5) 7-17 (21) mm. long; peduncles erect, 4-9.5 cm. long; racemes loosely (10) 15-27-flowered, the axis 4-8.5 cm. long (rarely shorter in depauperate, subterminal racemes); calyx 6.5-8 mm. long, the deeply campanulate or cylindric tube 4.6-5.7 mm. long, 2.1-3.4 mm. in diameter, the teeth (1.5) 1.7-2.3 mm. long; petals pink-purple or lavender with white wing-tips, at first drying bluish, the color fugacious in the herbarium; banner 13.2-17 mm. long, 6.4-9.6 mm. wide; wings 11-14.3 mm., the claws 4.3-5.4 (6.6) mm., the blades 7.5-10 mm. long, 1.8-2.8 mm. wide; keel 10-12 (12.5) mm., the claws 4.6-5.4 (6.4) mm., the blades 5.9-6.8 mm. long; pod 1.5-2.5 cm. long, (0.7) 0.9-1.5 cm. in diameter, usually strongly inflated, with broadly ovoid body abruptly contracted into a short, triangular, slightly incurved beak, but rarely less inflated, lunately lance-acuminate in profile, gently incurved from near the base, the papery-membranous, glabrous, unmottled valves pale green turning pallid and lustrous in age; ovules 21-31.—Collections: 16 (ii); representative: Eastwood & Howell 9155 (CAS, RSA); C. L. Hitchcock 3025 (F, POM, WS, WTU); Jones 25,443 (POM); Ripley & Barneby 8514 (CAS, RSA); McClintock 52-179 (CAS, NY), 52-275 (CAS, RSA).

Gullied badlands and desert flats, in sand or clay derived from sandstone, occasionally in volcanic gravel, 2750-4700 (6300) feet, locally plentiful and rather common in the valleys of the upper Virgin River and Kanab Creek, south to the north slope of the Kaibab Plateau, Toroweap Valley, and House Rock Valley, in Washington (? and southern Kane) County, Utah, and northern Mohave and northwestern Coconino Counties, Arizona; possibly in adjoining Nevada (cf. infra).—Map No. 131.—April to June.

Astragalus lentiginosus var. vitreus (shining like glass, of the ripe pod) Barneby in Leafl. West. Bot. 4: 119, Pl. III, figs. 30—33. 1945.—" ... 5 miles west of Leeds, Washington County, Utah, Bassett Maguire & H. L. Blood No. 4413 ... "—Holotypus, collected May 19, 1933, POM! isotypus, UTC!

The var. vitreus might be visualized as a large-flowered version of some glabrescent state of var. Fremontii, or alternatively as a phase of var. diphysus in which the racemes have become drawn out and loose and the pod papery-membranous and transparent rather than stiffly papery or leathery and opaque. In the trough lying between the Zion Escarpment and the Kaibab Plateau, var. vitreus is the only freckled milk-vetch with green leaves and stems and with glabrous ovary and pod. Forms intermediate between var. vitreus and var. stramineus, which occur so close together (although not truly sympatric) in the Virgin Valley, are to be expected but have not yet turned up. A specimen from Star Springs on the south slope of the Henry Mountains (Harrison 11,521, US) has been identified by me as var. vitreus, probably mistakenly, for material collected subsequently in the same area (McVaugh 14,509, CAS, NY) seems better referred to var. diphysus. An indifferent specimen from Mica Spring in eastern Clark County, Nevada (Jones 5272d, POM) is sugestive both of var. vitreus and of var. ambiguus; but as it cannot be identified with any assurance, it has been omitted from the maps.