Corticalous species of the lichen genus Porina (Porinaceae) in the Yambaru (or Yanbaru) area, Okinawa I., Japan were investigated, and six species were recognized: P. eminentior, P. farinosa, P. internigrans, P. mastoidea, P. tetracerae and P. Yambaruensis H. Harsda sp. nov. Descriptions and illustrations are provided for each species based on specimens from the Yambaru area. Asia, Japan, corticolous, lichens, Porina