Leptogium quercicola (Collemataceae), a new corticolous species, is described from central and south-eastern Spain. It is closely related to L. lichenoides, but differs in the development of dense fruticolous cushions, with lobes narrower than the smallest known forms of L. lichenoides. Moreover, spore length and width of the two taxa are significantly different. In addition, the two species differ ecologically; L. quercicola growing directly on bark of Quercus spp., while L. lichenoides colonizes rocks, soil and bark but always among mosses.