Astragalus distortus Torrey & A. Gray var. distortus . Phen: (Late Mar-) May-Jul. Hab: Shale barrens and other dry, shaley places, westwards in a variety of dry open and wooded habitats. Dist: A. distortus is interpreted by Barneby (1964) (and followed by Cronquist  and Isely ) to consist of 2 varieties: var. distortus, occurring in the s. Midwest from IL, MO, and OK south to MS, LA, and AR, and disjunct in n. and sc. VA, e. WV, and w. MD, and var. engelmannii (Sheldon) M.E. Jones, of TX and ne. LA
Origin/Endemic status: Native
Taxonomy Comments: The two varieties seem fairly readily distinguishable morphologically in the Midwest. Appalachian var. distortus complicates the issue, since it approaches var. engelmannii in flower size and matches it in ovule number. The Appalachian plant, with a combination of morphologic characters not matching the two named varieties and far allopatric from them might better be considered a distinct variety. Further study is needed.
Synonymy: = Ar, C, K1, K3, K4, NcTx, SE3, Tx, Va, Barneby (1964), Isely (1998); = Holcophacos distortus (Torr. & A.Gray) Rydb. – S; < Astragalus distortus Torr. & A.Gray – F, G, GrPl, Il