Monographs Details: Astragalus atratus var. inseptus Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
Family:Fabaceae
Description:Variety Description - Wholly similar to var. atratus, the herbage greenish, the leaflets glabrous above; stipules 1.5-8 mm. long; leaflets 9-15, narrowly oblong-oblanceolate to linear-oblong or (in some lower leaves) oval, obtuse or notched, 3 13 mm. long, all jointed; calyx 4.7-6.4 mm. long, the tube 3.3-4.2 mm. long, 2.2-3.1 mm. in diameter, the teeth 1.5-2.2 mm. long; petals whitish, the banner and keel-tip faintly lilac-tinged; banner 8-11.3 mm. long, 5.8-7.2 mm. wide; wings 0.6-1.8 mm. longer, 9.6-12 mm. long, the claws 3.4-5.1 mm., the obliquely obovate or half- obovate blades 6.2-7.5 mm. long, 3-4.5 mm. wide, erose-emarginate or very shallowly notched at apex; keel 7.2-9.1 mm. long, the claws 3.4—5 mm., the blades 4-4.8 mm. long, 2.4-2.9 mm. wide; pod subsessile or very shortly stipitate, the stipe 0.3-1.1 mm. long, the body 1.2-1.8 cm. long, 3-4.2 mm. in diameter, in outline and texture like that of var. atratus but the septum obsolete; ovules (14)16-21.

Distribution and Ecology - Stony flats, in stiff soil moist in spring, ± 5000 feet, known only from the type-locality in the foothills at the northern edge of the Snake River Plains in Camas County, Idaho.—Map No. 55.—May and June.

Discussion:The plants described as var. inseptus closely resemble the more leafy states of var. atratus, differing in the almost entire wings-petals and strictly unilocular pod. In the last respect they are like var. owyheensis, but the coarser growth-habit, well-developed leaflets all jointed to the rachis, and stiff-walled pod are characteristic.
Distribution:Idaho United States of America North America|