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 traditional recognition of Epacridaceae and Empetraceae as distinct from Ericaceae should be reevaluated. These studies used morphological data and nucleotide sequence from the chloroplast encodedrbcL (rubisco, large subunit) gene. They indicated that Ericaceae as presently recognized are paraphyletic and should include Epacridaceae and Empetraceae, as well as Pyrolaceae and Monotropaceae. A study of nuclear ribosomal 18s gene sequences was undertaken to test the hypothesis that Epacridaceae form a monophyletic derived group out of Ericaceae. The problematic taxaPrionotesandLebetanthuswere included because these taxa have been alternatively placed in Ericaceae and Epacridaceae. Representatives of the herbaceous (Pyrolaceae) and mycoparasitic taxa (non-chlorophyllous, Monotropaceae) were also included in the study. Taxa that represented lineages peripherally related to Ericaceae and Epacridaceae were included in order to develop a better understanding of the relationships and limits of Ericales. Parsimony analyses of 18s sequences and a combined analysis of 18s+rbcL sequences were performed. Results of these analyses indicate strong support for the recognition of a monophyletic Ericaceae that includes Empetraceae, Epacridaceae, Pyrolaceae, and Monotropaceae.