Occurrence of Halophila decipiens Ostenfeld (Hydrocharitaceae) in Okinawa Island, Japan

Abstract

Specimens of Halophila decipiens Ostenfeld were collected at Sesoko Island and Nakagusuku Bay at Okinawa Island, the Ryukyu Islands, southern Japan. H. decipiens grows sparsely on coral sand at depths of 15-18 m. This is the first record of the occurrence of H. decipiens in Japanese waters and is the most northerly locality of this species in the Pacific Ocean. The morphological and anatomical characters as well as the ecological preference of the Okinawan H. decipiens are discussed and illustrated. © 1995.