Umbilicaria mammulata
DIAGNOSTIC FEATURES: Large, smooth, leathery, irregular thallus, usually torn or contorted; undersurface a velvety nap of short, black rhizines; not pitted; NIS; compare with U. vellea which has longer brownish rhizines scattered among the short, black ones.
ECOLOGY: An Appalachian-Boreal species; scattered in southeastern Ohio, common on boulders and rock outcrops in open woods, on sandstone exclusively, preferring moist, partially shaded habitats.