This species is known only from its filamentous gametophytes; see W for review of literature. It is known only from ceilings or back walls of overhanging cliffs in Appalachian regions and the Shawnee Hills. Records of Cranfill (1980) and Farrar (1992) are mapped here but need better documentation. A distinct, thallose gametophyte that is also expected in Ky. is Hymenophyllum tayloriae Farrar & Raine. That southern Appalachian species occurs on the Cumberland Plateau in Tenn. close to Ky. (Ch, W).