Range Extension For Riccia Nipponica And Comments On The R. Crystallina Complex (Ricciaceae, Hepaticae)

For Riccia nipponica S. Hatt., previously regarded as a Japanese endemic, the paper gives the first records from the southern flank of the Russian Far East and Guizhou Province of China. These records considerably enlarge its known distribution area. New data on its morphological variability, ecology and distribution patterns are summarized and analyzed based on study of available material from East Asia. A morphological description and figures are given, with a key in table form for it and related taxa. Although closely related to the sub-cosmopolitan R. crystallina L., R. nipponica merits species rank.