Astragalus umbraticus

Title

Astragalus umbraticus

Authors

Rupert C. Barneby

Scientific Name

Astragalus umbraticus E.Sheld.

Description

122. Astragalus umbraticus

Rather tall but often quite slender, appearing nearly glabrous but bearing a few scattered, straight, appressed or narrowly ascending hairs up to 0.3-0.7 mm. long on the stems distally and on the margins and midribs of the deep or pale green leaflets, the inflorescence thinly black-strigulose; stems several, diffuse or ascending from the knotty root-crown or shortly forking caudex, (2) 2.5-5 dm. long, pale green becoming stramineous, striate, simple or nearly so, stipules 3.5-9.5 mm. long, the lowest early becoming papery and brownish, embracing 3/4 to nearly the whole stem’s circumference, the upper ones submembranous, longer and narrower, triangular or lance-acuminate, thinly ciliate; leaves 4-12 cm. long, the uppermost shortly petioled or subsessile, with (11) 15-23 broadly oblong, ovate, or obovate, or (in some lower leaves) suborbicular, retuse or abruptly short-acuminate, flat, thin-textured leaflets (4) 6-16 (20) mm. long; peduncles erect or incurved-ascending, 5-12 cm. long, ± equaling the leaf; racemes loosely but shortly 10-25- flowered, the flowers early horizontal, at length declined, the axis little elongating, (1.5) 2-5 cm. long in fruit; bracts membranous, narrowly lanceolate, (1.7) 2-4 mm. long; pedicels at anthesis ascending or a little arched outward, 0.6-1.2 mm. long, in fruit ascending or more strongly arched, a little thickened, scarcely longer; bracteoles 0; calyx 5.2-7 mm. long, strigulose or pilosulous with dark hairs, the somewhat oblique disc 0.7-1.2 mm. deep, the campanulate tube 3.1-4 mm. long, 2.1-3.2 mm. in diameter, the subulate or lance-subulate teeth 2.1-3.2 mm. long; petals greenish-white, often drying cream-color, immaculate; banner recurved through 40-60°, narrowly to broadly ovate-cuneate or rhombic-elliptic, 10-14 mm. long, 5-8 mm. wide; wings 8.4-11 mm. long, the claws 3.5-4.8 mm., the claws 3.5-4.8 mm., the oblong-oblanceolate, obtuse, obliquely truncate and erose, or shallowly emarginate, slightly incurved blades 6-7.6 mm. long, 2-2.9 mm. wide; keel 7.7-10 mm. long, the claws 3.7-5.6 mm., the half-obovate or lunately half-elliptic blades 3.8-5 mm. long, 2.1—3 mm. wide, incurved through 95-100° to the bluntly deltoid apex; anthers (0.35) 0.4—0.55 mm. long; pod spreading or declined, stipitate but the obscure stipe only 0.8-1.9 mm. long, concealed by the calyx, the body lunately or falcately linear-lanceolate or linear in profile, evenly incurved through ¼-½ circle, 1.4—2.4 cm. long, 2.6—3.6 mm. in diameter, cuneate at base, acuminate and cuspidate at apex, laterally compressed- triquetrous, with low-convex lateral and narrower, narrowly but deeply grooved dorsal faces, keeled ventrally by the salient suture, the firmly papery, glabrous valves at first green becoming stramineous and ultimately blackish, delicately cross- reticulate, inflexed as a complete septum 1.5—2.3 mm. wide; ovules 10—15; seeds compressed-quadrangular, brown, smooth but dull, 2.2-2.6 mm. long.—Collections: 15 (o); representative: Jones (from Glendale) in 1902 (CAS, NY, POM); C. L. Hitchcock 19,381 (UC, WS); W. H. Baker 858 (ID, RSA); Tracy 4575 (UC); Peck 8209 (WILLU); Quick 57-24 (CAS).