ABSTRACT: The foliicolous lichen Aspidothelium gemmiferum is described from lowland rainforest along the northern coast of Papua New Guinea; it is easily distinguished by the production of disk-like isidia on the prothallus. A key to all known species of Aspidothelium is provided.

NOMENCLATURAL NOVELTIES:
Aspidothelium gemmiferum Sérus. & Lücking, p. 44