Astragalus Sheldoni

Title

Astragalus Sheldoni

Authors

Rupert C. Barneby

Scientific Name

Astragalus sheldonii (Rydb.) Barneby

Description

156. Astragalus Sheldoni

Usually stout and rather coarse, with a thick, woody taproot and shortly forking suffruticulose caudex, strigose-pilosulous with fine, ascending and incumbent hairs up to 0.5-0.9 mm. long, the pale green or stramineous, striate stems thinly so, the herbage greenish or cinereous on the lower surface, the leaflets glabrous above; stems several, erect and ascending in clumps, simple above the immediate base, (3) 5-38 cm. long, composed of 3-7 developed internodes up to 2.5-12 cm. long, the whole commonly shorter, sometimes a little longer than the longest inflorescence; stipules 3-10 mm. long, the lowest adnate (sometimes through 4 mm.) to the petiole-base, papery-scarious or early becoming so, ovate or ovate- acuminate, amplexicaul-decurrent around half or a little more of the stem s circumference, the upper ones narrower, more shortly adnate, with lance-acuminate, mostly erect, subherbaceous blades, their margins commonly beset with a few minute processes; leaves 7-19 cm. long, the lowest long-petioled, the upper more shortly so, with (17) 23-35 (39) oblong-obovate, elhptic, or narrowly oblanceolate, retuse, obtuse, or sometimes subacute, flat leaflets 5—22 mm. long, peduncles stout, stiffly erect, (11) 16-30 cm. long; racemes loosely 10-30 (35)-flowered, the flowers nodding and at early anthesis retrorsely imbricated, the axis early elongating, (3) 6-16 cm. long in fruit; bracts submembranous, linear- or lance- acuminate, 2.5-9 mm. long; pedicels at anthesis arched outward, 1.3-2 mm. long, in fruit clavately thickened, erect, 2.5-6 mm. long; bracteoles 0-2; calyx 8.5-12.6 mm. long, thinly strigulose-pilosulous with black or mixed black and white hairs, the oblique disc 0.9-1.4 mm. deep, the membranous, pallid, deeply campanulate tube 5.6-7.5 mm. long, 3.5-4.S mm. in diameter, the subulate or linear-subulate teeth 2-5.2 (6) mm. long, either erect or arcuately spreading or recurved the whole becoming papery-scarious, ruptured but marcescent; petals white or creamy-white immaculate; banner gently recurved through about 45°, rhombic-oblanceolate or -obovate, shallowly notched. 15.5-21.5 mm. long. 7-11 mm. wide; wings 13.4-19 mm. long, the claws 6.2-9 mm. the nearly straight, obliquely oblong-oblanceolate, obtuse or emarginate blades 8-11.8 mm. long. 2.5-4.2 mm. wide; keel 11.5-14.4 mm. long. the claws 5.9-8 4 mm., the lunately half-elhptic blades 5.6-7.6 mm. long. (3.2) 3.7-4 mm. wide, gently or rather abruptly incurved through 75-85 (90°) to the sharply deltoid apex; anthers 0.7-0.9 mm. long, pod erect, sessile or elevated on an obscure, stout stipe up to 1.5 mm. long, the body narrowly oblong-ellipsoid, (1.5) 1.7-2.3 cm. long, (4) 4.5-6.3 mm. in diameter, straight or a trifle incurved, abruptly obtuse or truncate at base, contracted distally into a triangular-acuminate, sharply cuspidate, laterally compressed beak, otherwise obcompressed, keeled ventrally by the prominent thick ventral suture, openly grooved dorsally, the green, fleshy, at length leathery and stramineous transversely rugulose-reticulate valves either minutely strigulose with black complete septum 1-1.6 mm. wide; ovules (20) 24-31; seeds brown, smooth but dull, 2.3-2.6 mm. long.-Collections: 22 (i); representative; Maguire & Holmgren 26,711 (CAS, WS); J. R. Murphy 73 (NY, SWU, WS); J. & C. Christ 16,553, 16,576 (NY, RSA); Ripley & Barneby 10,744 (CAS, RSA); W. H. Baker 6720 (ID, RSA).