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Williams' Milkvetch

Astragalus williamsii Rydb.

Comprehensive Description

provided by North American Flora
Atelophragma williamsii Rydb. Bull. Torrey Club 55: 132. 1928.
Astragalus Williamsii Rydb. Bull. N. Y. Bot. Gard. 2: 175. 1901. Astragalus Gormaui Wight; M. E. Jones, Rev. Astrag. 132. 1923.
A perennial, with a cespitose caudex; stems ascending or erect, 2-4 dm. high, more or less 4-angled, glabrous, light-green, in age straw-colored; leaves 5-10 cm. long, ascending; stipules ovate or lanceolate, 3-6 mm. long, free; leaflets 9-11, oval to linear, 1.5-3.5 cm. long, 4-12 mm. wide, obtuse, or the broader ones retuse, perfectly glabrous; peduncles 1-1.5 dm. long; racemes at first short, in fruit about 1 dm. long; bracts oblong, obtuse, straw-colored, 3 mm. long; pedicels 1-2 mm. long; calyx black-hairy, the tube about 3 mm. long, the teeth less than 1 mm. long, deltoid, obtuse; corolla ochroleucous, with a purplish-tipped keel; banner about 1 cm. long, narrowly obovate, slightly arched, retuse at the apex; wings shorter, the blade longer than the claw, with a long reflexed auricle; keel-petals still shorter, the blade obliquely obovate, stronglyarched and rounded at the apex; pod erect, subsessile, the body 10-14 mm. long, 4 mm. wide, nearly terete, strigulose with black and white hairs or in age glabrate, deeply sulcate on the lower suture, the septum about 1 mm. wide, becoming narrower upwards and extending onlyhalf the length of the pod; seeds obliquely reniform, brownish-black.
Type locality: Big Salmon, Yukon.
Distribution: Yukon and Alaska.
bibliographic citation
Per Axel Rydberg. 1919. (ROSALES); FABACEAE; PSORALEAE. North American flora. vol 24(1). New York Botanical Garden, New York, NY
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