Observations on Riccia bifurca Hoffm. and other species of Riccia L. in the British Isles

Abstract

Attention is drawn to some of the characters of Riccia bifurca from Cornwall, especially the long-persistent, orange-brown, canaliculate thalli and the small-celled compact tissues, and its differences from other species are discussed. A revision of material shows that all records from elsewhere in the British Isles are erroneous or unsupported by specimens and thus extremely doubtful. Additional studies show that R. crozalsii is confined to south and west Britain, several records, including all the Irish ones, being erroneous, and that R. michelii and R. ciliata should be removed from the British List.