Monographs Details: Astragalus ceramicus var. apus Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
Description:Latin Diagnosis - leguminibus stipite obsoleto arete sessilibus ab aliis omnibus speciei formis insuper procul allopatricis diversa—Omnia caetera var. filifolii (Gray) F. J. Hermann.

Variety Description - Wholly similar to var. filifolius except for the sessile pod; lateral leaflets wanting or nearly so; pod 2—4 cm. long, ± 1.5—2.4 cm. in diameter.

Distribution and Ecology - Dunes and sandy flats, ± 4400-4800 feet, apparently not uncommon about the east end of the Snake River Plains, from near the sinks of the Lost Rivers in Butte County, east to western Madison and northwestern Bonneville Counties, Idaho.—Map No. 33.—May to July.

Discussion:In its basifixed pubescence, almost complete lack of lateral leaflets, flowers of moderate size, and in number of ovules, the painted milk-vetch of the Snake River Plains closely matches some forms of A. ceramicus var. filifolius from east of the Rocky Mountains, but it apparently differs consistently in the sessile pod. The known range of var. apus extends over an area about sixty miles in diameter and lies distant two hundred miles west from the last outpost of var. filifolius on the upper Platte and Big Horn Rivers in Wyoming. The variety was first collected near Fort Hall, in 1845 or 1846, by Joseph Burke (K).
Distribution:Idaho United States of America North America|