抄録
Japanese species of the sect. Riccia of the genus Riccia (Ricciaceae, Hepatics) were taxonomically revised and four species were recognized: they are R. beyrichiana Hampe ex Lehm., R. bifurca Hoffm, R. glauca L., and R. subbifurca Warnst. ex Croz. Most specimens previously named by Japanese bryologists as R. glauca are revealed to be R. bifurca, which is commonly distributed from Hokkaido to Kyushu. Riccia glauca is, on the contrary, very rare in Japan. Both R. beyrichiana and R. subbifurca are newly reported from Japan. Descriptions, diagnostic characters, distribution and illustrations of these four species are provided based on Japanese plants.
