This has been recently collected from the Shawnee Hills region of Ky. in HOPK (M. Hines for EKY), GRAY and HART (R. Seymour, pers. comm.). The species is widely distributed across southeastern states, but it concentrated on the Coastal Plain and rare to absent in much of the Ohio Valley and Appalachian regions (K, W). H. gymnanthum is typical of hydroxeric openings on acid soils. It appears close to mutilum and boreale but differs as follows (W): sepals broadest near the base (versus near middle); inflorescence with few or no normally sized leaves, these only low in the inflorescence, giving the inflorescence a naked appearance (versus with many normally sized leaves and leaflike bracts).