Astragalus Webberi

  • Title

    Astragalus Webberi

  • Author(s)

    Rupert C. Barneby

  • Scientific Name

    Astragalus webberi A.Gray

  • Description

    174. Astragalus Webberi

    Rather robust, diffuse, leafy, densely strigulose nearly throughout with fine, straight, appressed (and often a few narrowly ascending) hairs up to 0.35-0.6 (0 7) mm long, the herbage greenish-canescent and often satiny, sometimes becoming silvery in age, the leaflets equally pubescent on both sides, the inflorescence ± dark hairy; stems numerous, decumbent and weakly ascending, (1.5) 2.5-5 dm. long, slender, leafless, purplish at base, subterranean for a space of (0) 1-5.5 cm. stouter upon emergence, simple or rarely spurred at 1-2 nodes preceding the first peduncle, floriferous from near or below the middle; stipules (1.5) 2-7 mm. long, dimorphic, those at the lowest nodes amplexicaul and connate into a campanulate papery-scarious, bidentate sheath (sometimes ruptured in age), the median and upper ones herbaceous and longer, ovate- or triangular-acuminate, or lanceolate, the squarrose or deflexed blades pubescent both within and ciliate and often beset with a few minute processes; leaves (2.5) 4-13 (15) cm. long, shortly petioled or the upper ones subsessile, with (9) 15-21 (25) broadly to narrowly oblanceolate or elliptic-oblanceolate, obtuse, shallowly retuse, truncate and mucronulate, or subacute, flat leaflets (0.5) 1-2.5 (3.5) cm. long; peduncles rather stout, (4.5) 6-15 cm. long, incurved-ascending at anthesis, reclinate in fruit; racemes loosely 6-12 (14)-flowered, the flowers ascending or somewhat spreading in age, the axis 2.5-10 cm. long in fruit; bracts submembranous, pallid or rarely purplish, lanceolate or ovate-acuminate, 1.3-4.5 mm. long; pedicels rather stout, ascending or a little arched outward, at anthesis (1) 1.2-2 mm., in fruit thickened, 2.2-3.5 mm. long; bracteoles 0-2; calyx 8.8-11.8 mm. long, loosely strigulose with mixed black or fuscous and pallid hairs, the strongly oblique or subsymmetric disc 1.3-2.2 mm. deep, the membranous, deeply campanulate or subcylindric tube 6.3-7.5 mm. long 2.9-4 mm. in diameter, the lance-subulate teeth 2.5-4.3 mm. long; petals ochroleucous, immaculate; banner evenly but quite strongly recurved (through 50-75°), narrowly to broadly rhombic-elliptic or -oblanceolate, notched or subentire at apex, 15.4—18.8 mm. long, 6-8.6 mm. wide; wings 13.2-16.8 mm. long, the claws 6.4-8.1 mm., the oblong-oblanceolate or linear-oblong, obtuse, truncate, or erose-emarginate, slightly incurved blades 7.7-10.4 mm. long, 2.5-3.8 mm. wide; keel 11.4—13.7 mm. long, the half-obovate blades 5.4—7 mm. long, 2.8-3.8 mm. wide, abruptly incurved through 90-95° to the rounded or sharply deltoid apex; anthers (0.6) 0.7-1.05 mm. long; pod ascending or loosely spreading-ascending (humistrate), sessile, obliquely oblong-ellipsoid, slightly incurved, (2) 2.5-3.5 cm. long, (7) 8-12 mm. in diameter, rounded or broadly cuneate at base, contracted distally into a short, triangular- or deltoid-acuminate, stiffly short- cuspidate, laterally compressed beak, otherwise a little obcompressed, obtusely carinate ventrally by the salient, cordlike suture, the dorsal face low-convex, flat or a trifle depressed, also carinate by a more slender, often undulate suture, the thick, fleshy, green or red-spotted, glabrous valves becoming brownish-stramineous, stiffly leathery or almost woody, reticulate and often rugulose on the angles, wrinkled lengthwise, not inflexed, or inflexed as a rudimentary septum up to 1.5 mm. wide; ovules 20-26; seeds brown or greenish-brown, sparsely pitted, dull, 3.1-4 mm. long.—Collections: 8(ii); representative: Mrs. Clemens (from Taylorville) in Sept. and May, 1920 (CAS, NY); Barneby & Howell 11,478 (CAS, NY, POM, RSA); W. G. Follett (from Virgilia) in 1930 (CAS).

    Open brushy slopes and flats in xeric pine forest or mixed pine and oak forest, 2700-3550 feet, possibly higher (to 5000 feet acc. Jepson), local but locally plentiful about the headwaters of the Feather River in Plumas and perhaps adjoining Sierra County, California.—Map. No. 70.—May to July, the fruit long persisting.

    Astragalus Webberi (a friend of Lemmon, perhaps connected with the California Geological Survey) Gray ap. Brew. & Wats., Bot. Calif. 1: 154. 1876.—"Indian and Sierra Valley, in the northeastern part of the Sierra Nevada, Lemmon, Mrs. Pulsifer-Ames"—Holotypus (Lemmon, from Sierra County in 1874), GH (2 sheets); paratypus (Mrs. Ames from Plumas County), GH!—Collections of Lemmon and of Mrs. Ames at NY and US, dated 1875, are authentic but perhaps no more than topotypi.—Tragacantha Webberi (Gray) O. Kze., Rev. Gen. 949. 1891. Xylophacos Webberi (Gray) Rydb. in Bull. Torr. Club 52: 151. 1925.

    The Webber milk-vetch is a rather coarse astragalus, one which might easily be passed off as commonplace until the finer points of its structure are appreciated. It is one of very few members of the genus native to the west slope of the northern Sierra Nevada, and since the others have papery inflated fruits borne on a long stipe, there should be no difficulty in identifying mature specimens. However, on account of the toughness of the woody root and the o en unwieldy length of the stems, the basal parts bearing the characteristic stipule-sheaths are seldom collected; and since the fruits come to maturity slowly, after all flowers are past, the herbarium material is mostly incomplete. A feature to look for in poor specimens of A. Webberi is the fine, appressed, lustrous vesture of the leaves, which is not very noticeable in the living plant but imparts to the dried foliage an instantly recognizable satiny sheen.

    The accompanying map shows only those stations for A. Webberi that have been recorded and identified precisely, all in Plumas County. Some early collections of the species were labeled Sierra County or Sierra Valley, but both terms (the second especially) were used with considerable vagueness by Lemmon and his associates in the northern Sierra settlements. There is no modern collection from east of the Sierra crest.