Although widespread in most humid temperate regions of North America, this species is curiously uncommon in central and lower sections of the Mississippi Rv. watershed (K). Within Ky. this species is largely restricted to Appalachian regions or adjacent hills. This is the only North American species of Orobancheae that is restricted to woodlands, where it is reportedly parasitic on several kinds of plant (F, Cr), including Saxifragales and Asterales. Aphyllon differs as follows (W): flowers solitary on a long pedicel as a scape, the true stem largely underground (versus several-many, sessile or subsessile in a dense spike).