PHYLOGENETIC-RELATIONSHIPS OF EMPETRACEAE, EPACRIDACEAE, ERICACEAE, MONOTROPACEAE, AND PYROLACEAE - EVIDENCE FROM NUCLEAR RIBOSOMAL 18S SEQUENCE DATA

Recent studies of phylogenetic relationships have indicated that the t raditional recognition of Epacridaceae and Empetraceae as distinct fro m Ericaceae should be reevaluated. These studies used morphological da ta and nucleotide sequence from the chloroplast encoded rbcL (rubisco, large subunit) gene. They indicated that Ericaceae as presently recog nized are paraphyletic and should include Epacridaceae and Empetraceae , as well as Pyrolaceae and Monotropaceae. A study of nuclear ribosoma l 18s gene sequences was undertaken to test the hypothesis that Epacri daceae form a monophyletic derived group out of Ericaceae. The problem atic taxa Prionotes and Lebetanthus were included because these taxa h ave been alternatively placed in Ericaceae and Epacridaceae. Represent atives of the herbaceous (Pyrolaceae) and mycoparasitic taxa (non-chlo rophyllous, Monotropaceae) were also included in the study. Taxa that represented lineages peripherally related to Ericaceae and Epacridacea e were included in order to develop a better understanding of the rela tionships and limits of Ericales. Parsimony analyses of 18s sequences and a combined analysis of 18s + rbcL sequences were performed. Result s of these analyses indicate strong support for the recognition of a m onophyletic Ericaceae that includes Empetraceae, Epacridaceae, Pyrolac eae, and Monotropaceae. (C) 1996 Annals of Botany Company