Phacelia covillei S. Watson ex A. Gray. Phen: Apr; May. Hab: Rich soils of floodplains, and contiguous terraces and slopes. Dist: Ranging in three disjunct areas: c. NC and sc. VA (in the drainages of the Cape Fear, Tar, and Roanoke rivers); DC, n. VA, and sc. MD (in the drainage of the Potomac River); and disjunct at scattered locations w. WV, s. OH, sw. IN, and s. MO (in the drainage of the Ohio River and its tributaries, except the MO occurrence) (Sewell & Vincent 2006)
Origin/Endemic status: Endemic
Taxonomy Comments: Closely similar to P. ranunculacea (with which it is sympatric in the lower Ohio River area), but consistently distinguishable based on subtle characters (Sewell & Vincent 2006). Chuang & Constance (1977) felt that P. covillei and P. ranunculacea (sensu stricto) have numerous characteristics that rendered their inclusion in Phacelia uncomfortable (also see discussion in Constance 1949 and Gillett 1968), but Sewell & Vincent (2006) countered this idea. See Nemophila aphylla for suggestions on distinguishing these three superficially similar species.
Synonymy: = K1, K3, K4, Va, Sewell & Vincent (2006); < Phacelia ranunculacea (Nutt.) Constance – C, F, G, Il, RAB, Constance (1949)