Astragalus Williamsii

Commonly rather tall, sparsely and sometimes only minutely strigulose with filiform or somewhat flattened and scalelike, appressed or subappressed hairs up to 0.2-0.65 mm. long, the herbage green or perhaps somewhat glaucescent when fresh, of thick texture, the leaflets glabrous above and often almost so beneath, the stems sometimes more densely pubescent at base than distally; stems several, erect and ascending in clumps from the knotty root-crown, 1.8-3.5 (5) dm. long, simple, at base leafless, purplish, becoming stramineous and striate upward, floriferous from 1-4 nodes beyond the middle, the inflorescences projected well beyond the leafy part of the plant; stipules 3—9 mm. long, dimorphic, the lowest oblong- obovate, several-nerved, united to the suppressed petiole, fully amplexicaul, either free or shortly connate, the median and upper ones narrower, less strongly amplexicaul, the uppermost lanceolate or narrowly triangular, membranous or thinly herbaceous distally, the blades often deflexed, all glabrous dorsally but commonly thinly ciliate and beset with a few marginal processes; leaves 2.5-8.5 (10) cm. long, the lowest shortly petioled, the rest subsessile, with (3) 5-15 firmly petio-lulate, linear-oblong, narrowly oblanceolate or lanceolate, more rarely oblong-obovate or even broadly obovate, retuse or sometimes obtuse, flat or loosely folded, dorsally keeled leaflets 6-34 (40) mm. long, the terminal one often a little longer than the last pair; peduncles stiffly erect, (3) 4-16 (20) cm. long, the earliest and stoutest greatly surpassing the leaf; racemes at first anthesis compactly 12-30 (35)-flowered, the flowers at first ascending, then nodding, the axis early elongating, 3-11.5 (14) cm. long in fruit; bracts membranous, pallid, triangular-lanceolate, lance-acuminate, or linear-caudate, (1.5) 2.5-9 mm. long; pedicels straight and ascending or a little arched outward, at anthesis 1-2.4 mm., in fruit a trifle thickened and 1.4—3.5 mm. long, subpersistent; bracteoles 0; calyx 4.3-6.7 mm. long, densely but shortly strigulose with black mixed with a few (rarely many) white hairs, the slightly oblique disc (0.6) 0.9-1.2 mm. deep, the tube 3.4-4.8 mm. long, 2.8-3.5 mm. in diameter, the broadly subulate or triangular-subulate teeth 0.9-2.8 mm. long, the ventral pair broadest but either longest or shortest, the ventral sinus very broad, the orifice oblique, the whole becoming papery, ruptured, marcescent; petals whitish or ochroleucous, often drying yellowish, the keel- tip maculate; banner obovate- or ovate-cuneate, -oblanceolate, or spatulate, deeply notched or subentire, (10) 11-14.6 mm. long, (5.4) 6-7.4 mm. wide; wings (8.1) 9.3-11.5 mm. long, the claws 3.3-4.5 mm., the oblong-oblanceolate, obliquely bidentate or emarginate, nearly straight blades (5.9) 6.8-8.6 mm. long, 2-3.3 mm. wide; keel (7) 7.7-9.1 mm. long, the claws (3.2) 3.6—4.5 mm., the half-obovate blades (4.4) 5.2-6.2 mm. long, 2.4-3 mm. wide, abruptly incurved through 85—95° to the rounded apex; anthers 0.4—0.6 mm. long; pod erect, sessile but elevated on an incipient gynophore 0.4—0.6 mm. long, the body obliquely ovoid or lance-ovoid, somewhat inflated but not bladdery, (7.5) 8.5-16 mm. long, 3.5-6.5 mm. in diameter, rounded at base, contracted at apex into a shortly conical, erect or commonly slightly declined beak, carinate ventrally by the rather prominent but filiform suture, deeply and openly sulcate dorsally, the thin, green, minutely black- and white-strigulose valves becoming brownish-stramineous, papery-membranous, delicately reticulate, inflexed in the lower ½—2/3 as a complete, hyaline, lenslike septum 1.2—2.3 mm. wide; ovules 6—8 (10); seeds purplish- green or -brown, smooth but dull, 2.6—3.1 mm. long.—Collections: 18 (o); representative: Porsild & Breitung 9668 (NY, UC); Tarleton 92a, 92b (NY); Eastwood 595 (CAS); Cody & Webster 4986, 5956 (DAO, NY), 5959 (DAO); Calder & Gillett 25,009, 25,838 (DAO).

Turfy creek banks and about aspens, in open woodlands and on sandy or gravelly river bluffs, locally plentiful along the upper Yukon and its tributaries in Yukon and eastcentral Alaska.—Map No. 5.—June and July.

Astragalus Williamsii (Robert Statham Williams, 1859-1945, distinguished bryologist) Rydb. in Bull. N. Y. Bot. Gard. 2: 175. 1901.—"The type was collected by R. S. Williams near Big Salmon, Yukon, August 22, 1899."—Holotypus (2 sheets), NY! isotypus, US!— Atelophragma Williamsii (Rydb.) Rydb. in Bull. Torr. Club 55: 132. 1928.

Astragalus Gormani (Martin Woodlock Gorman, 1853—1927, gifted amateur botanist, active chiefly in Oregon) Wight ex Jones, Rev. Astrag. 132, Pl. 26. 1923.—"In moist ground on creek banks near Fort Selkirk ... Gorman."—Holotypus, collected near Fort Selkirk on July 8, 1899, US! isotypi, ND, NY, ORE!

The Williams milk-vetch is an interesting and rather handsome species, resembling some of the coarser and greener forms of A. aboriginum in its stipules, mostly sessile leaves composed of about three to seven pairs of leaflets, and emarginate or bidentate wing-petals, but easily distinguished by the erect, sessile pod of papery-membranous texture which disjoints when ripe and separates into two halves. Some variation is found in the size of the flowers and the length of the calyx-teeth, which tend to be crowded toward the dorsal side of the calyx and away from the broad, deeply cut-back ventral sinus. The pod varies from shortly and plumply ovoid to lance-ovoid, but despite the variation in length the ovules remain almost constantly either three or four, exceptionally five pairs. The plants of Yukon Territory are very thinly pubescent, the stems and leaves appearing almost glabrous to the naked eye, but populations around Big Delta in the Tanana Valley, Alaska, are decidedly strigulose throughout except for the upper leaf-surface. According to Porsild (in Nat. Mus. Canad. Bull. 121: 239) the stems are slightly glutinous when fresh and the foliage somewhat fleshy. The fresh petals have been described by collectors as white, cream-colored, or yellow; they appear ochroleucous in dried specimens, but the bluish-purple keel-tip remains conspicuous.