Astragalus Osterhouti

Title

Astragalus Osterhouti

Author(s)

Rupert C. Barneby

Scientific Name

Astragalus osterhoutii M.E.Jones

Description

118. Astragalus Osterhouti

Stout and coarse, with a heavy, multicipital taproot, appearing almost glabrous, but the extremities of the stems, the lower surface of the upper leaves, and the inflorescence thinly strigulose with fine, sometimes flattened, appressed and narrowly ascending hairs up to 0.2-0.5 mm. long, the stems and herbage somewhat succulent, dark green; stems several or numerous, erect and ascending from the root-crown or shortly forking, shallowly buried caudex in dense bushy clumps, 2.5-4.5 dm. long, simple or few-branched, leafless at base, hollow and commonly zigzag distally; stipules 2-8 mm. long, dimorphic, those at the lowest (leafless) and sometimes the first leafy nodes the longest, connate into a scarious, subtruncate or shortly bidentate sheath, the median and upper ones shorter, becoming upwardly more nearly or quite herbaceous and progressively less connate, the uppermost deltoid or deltoid-acuminate, connate only at the very base, united by a stipular line, or free; leaves 3-8.5 cm. long, subsessile, with (5) 7-15 linear- oblong or oblanceolate, or (in the uppermost leaves) sometimes filiform, obtuse leaflets (0.6) 1-4 cm. long, not involute but with elevated margins, mostly narrowed at base into a short, pallid pseudopetiolule but not jointed, the terminal one decurrent into the rachis; peduncles stout, erect, (6) 8-14 cm. long, 1-3 from the upper axils, often appearing subterminal; racemes loosely 12-25-flowered, the flowers early spreading horizontally and then declined, the axis (2.5) 4.5-10 cm. long in fruit; bracts submembranous, ovate or lanceolate, 1-3.5 mm. long; pedicels at anthesis 2.5-5 mm. long, in fruit arcuate-recurved, not greatly thickened, 3-6 mm. long; bracteoles usually 1-2, minute; calyx 8.5-12 mm. long, strigulose with black or mixed black and white hairs, the oblique disc 0.8-1.6 mm. deep, the cylindro-campanulate or cylindric tube 7-10 mm. long, 3.5—4.7 mm. in diameter, strongly convex ventrally, the triangular-subulate teeth 0.8-2 mm. long, the ventral pair sometimes broadest and deltoid, all approximate on the lower side of the calyx, the ventral sinus thus very broad and deeply cut back, the orifice oblique, the whole becoming scarious, marcescent unruptured; petals white; banner gently recurved through 40-45°, 17—23.5 mm. long, the narrow, long-cuneate claw expanded into a lance-ovate or ovate, shallowly retuse blade 8.2-11.5 mm. wide; wings 16—21.3 mm. long, the claws 7.3-9.3 mm., the oblong-oblanceolate, obtuse, nearly straight blades 9.5-13 mm. long, 3-3.6 mm. wide; keel 12.3-14.8 mm. long, the claws 7.3—8.6 mm., the half-obovate blades 5.7—6.8 mm. long, 3— 3.7 mm. wide, rather abruptly incurved through 85—95° to the obtuse, deltoid or triangular, sometimes obscurely porrect apex; anthers 0.7-0.85 (0.9) mm. long; pod pendulous, stipitate, the stipe 2-6.5 mm. long, the linear-ellipsoid body 2.5-4.5cm. long, 3-4 mm. in diameter, straight or gently incurved either way, tapering at both ends, cuspidate at apex, strongly compressed laterally, bicarinate by the prominent sutures, low-convex on the faces, the fleshy, glabrous, shining green valves becoming stiffly papery, greenish-stramineous, reticulate but not rugulose, not inflexed; ovules 12-17, rarely 7-8; seeds brown, smooth but scarcely lustrous, 3.2—4 mm. long.—Collections: 5 (i); representative; W. A. Weber 4914 (SMU, TEX, WS), 4915 (CAS, SMU, TEX, WS); Ripley & Barneby 10,516 (CAS, NY, RSA, RM).

Forming colonies along gulches in denuded clay hills, on barren knolls, and at the foot of gullied bluffs, in stiff alkaline clay or shaley clay soils, sometimes growing up through sagebrush, 7500—7700 feet, very local, known only from the valley of the upper Grand River and affluent creeks in Grand County, Colorado (near Hot Sulphur Springs; north of Kremmling).—Map No. 49.—June to August.

Astragalus Osterhouti (George Everett Osterhout, 1858-1937, active in n. Colorado from 1893 onward) Jones, Rev. Astrag. 251, Pl. 64. 1923.-"Sulphur Springs, Grand Co Colorado. Nos. 3038 and 3235, July [17], 1905 and June [9], 1906, Geo. E. Osterhout. —Cotypi, from "about 4 miles below Sulphur Springs," POM! isotypi, NY, RM! Lonchophaca Osterhouti (Jones) Rydb. in N. Amer. Fl. 24: 313. 1929 ("Osterhoutii ).