This largely midwestern annual is known from about 21 states, but it is considered endangered or threatened in all except perhaps Mo., where it is just "uncommon" (Y). In Ky. auriculata is known only from prairie remnants of Fort Campbell in CHRI and the Chalk Ridge area in LEWI. Short (1840) also collected in from "wet lands in the barrens" (perhaps CHRI, check PH). The species is a hemiparasite, as in Agalinis; potential hosts (at least when cultivated) include Helianthus occidentalis and Rudbeckia fulgida sensu lato (Cunningham & Parr 1990). In Tenn. it is also known from Montgomery Co., adjacent to TRIG and CHRI (Ch). Some recent authors have combined this monotypic genus with Agalinis (Cr, W); 2n = 26. In recent phylogenetic analysis (Pettengill & Neel 2008), auriculata does have a near-basal position within the genus, sensu lato, but a few other species (divaricata, filicaulis, heterophylla, calycina) appear to have even deeper roots.