- 坪田博美・久保晴盛・向井誠二. 2009. 広島県宮島近海で見つかったヤマトウミヒルモHalophila nipponica J.Kuoについて. Hikobia 15: 339-347.
Tsubota, H., Kubo, H. & Mukai, S. 2009. A new finding of seagrass Halophila nipponica J.Kuo (Hydrocharitaceae) from Miyajima Island in Hiroshima Prefecture, SW Japan. Hikobia 15: 339-347.
The marine aquatic herb Halohila nipponica J.Kuo (Hydrocharitaceae, Monocotyledonae) is reported from an area near the SW part of Miyajima Island, Hiroshima Prefecture, Honshu, SW Japan (Aki-nada, W part of Set Inland Sea). The genus Halophila has a wide distribution range in the tropical and subtropical regions and extends to the temperate region around the Pacific, Atlantic and Indian Oceans, with its northern limit in the N part of Honshu, Japan, in the Pacific Ocean. H. nipponica was described recently, and its known distribution includes Japan (Honshu, Shikoku and Kyushu) and Korea. Morphological examination of field collections and molecular analysis of the internal transcribed spacer (ITS) sequence data of nuclear ribosomal DNA demonstrated that the specimens represent H. nipponica, not H. ovalis which has long been recognised in Hiroshima Pref. The vegetation of the habitat near Miyajima Island is a pure community of H. nipponica or mixed communites together with Zostera japonica Asch. & Graebn. and/or 'Z. marina' L. The habitat of this species is the lower part of the intertidal zone and upper part of the infralittoral zone, corresponding to the Z. japonica zone and Z. marina zone in the vertical distribution of seagrass communities. Because of the distance from other known localities, its environment being subject to minimal human disturbance, the differences in ITS sequence data when compared to that from other localities in Japan, and an old record of H. ovalis near Miyajima Is., the inclusion of H. ovalis from Hiroshima Pref. is a result of misidentification, and does not represent a recent introduction to the area.