Abstract
A new species of Sciaphila (Triuridaceae), S. sugimotoi Suetsugu & T. Nishioka, is described and illustrated from Ishigaki Island, Okinawa Prefecture, Japan. The new species is similar to S. arfakiana in having a stipitate globose to ellipsoid knob without hairs in apices of all male perianth segments. However, it is clearly distinguishable by its shorter pedicel, filament-connective not extended and thick stem. A key to the Japanese Sciaphila based on the whole flower characteristics and stylar characteristics, are provided for easy identification of these rare mycoheterotrophic plants.