ARE RED ALGAE PLANTS

For 200 years prior to the 1938 publication of H. F. Copeland, all aut horities (with one exception) classified red algae (Rhodophyta) within Kingdom Plantae or its equivalent. Copeland's reclassification of red algae within Kingdom Protista or Protoctista drew from an alternative tradition, dating to Cohn in 1867, in which red algae were viewed as the earliest or simplest eukaryotes. Analyses of ribosomal RNA (rRNA) sequence data initially favoured Copeland's reclassification. Many mor e rRNA gene (rDNA) sequences are now available from the eukaryote line ages most closely related to red algae, and based on these data, the h ypothesis that red algae and green plants: are sister groups cannot be rejected. An increasing body of sequence, intron-location and functio nal data from nuclear- and mitochondrially encoded proteins likewise s upports a sister-group relationship between red algae and green plants . Submerging Kingdoms Plantae, Animalia and Fungi into Eukarya would p rovide a more natural framework for the eventual resolution of whether red algae are plants or protists. (C) 1995 The Linnean Society of Lon don