DISTRIBUTION AND SYSTEMATICS OF BATRACHOSPERMUM (BATRACHOSPERMALES, RHODOPHYTA) IN NORTH-AMERICA .5. SECTION ARISTATA

Nine North American populations of Batrachospermum were compared to ei ght type specimens and one historically important specimen referable t o Section Aristata, using multivariate morphometrics and image analysi s. From this analysis and a comparison with the protologues of two oth er species, six species in the section are recognized worldwide: B. be raense Kumano, B. breutelii Rabenhorst (syn. B. dimorphum Kutzing), B. cayennense Montagne ex Kutzing (syn. B. aristatum Skuja), B. hypogynu m Ratnasabapathy ct Kumano, B. longiarticulatum Necchi and B. macrospo rum Montagne (syn. B. australe Collins, B. excelsum Montagne, B. oxycl adum Montagne). These species are distinguished by whorl shape, fascic le cell number, carposporangium dimensions and presence or absence of carposporangial septations. Only B. macrosporum is found in North Amer ica, ranging from the tropical rainforest of Belize to the coastal pla in of the eastern USA (Louisiana to New Jersey).