Phylogenetic relationships at the base of Ericaceae: Implications for vegetative and mycorrhizal evolution

Abstract

AbstractThe relationships among pyroloids, monotropoids, arbutoids and the remainder of Ericaceae continue to be unresolved even though significant progress has been made in understanding the phylogenetic structure of the family. This means that, in addition to uncertainty in classification, evolutionary patterns in vegetative structure and mycorrhizal diversity in the family have also been uncertain. This study analyzes nuclear, plastid and mitochondrial sequence data in order to provide a basis for classification and character analysis. Parsimony and maximum likelihood analyses of partitioned and combined data are largely in agreement; organellar data differ from nuclear data with respect to the position of pyroloids. Based on nuclear, plastid and combined data analyses, monotropoids are sister to arbutoids, and these are together sister to pyroloids, and thence to a core Ericaceae and finally to Enkianthus. This suggests that a reduction in woodiness and increased mycotrophy has occurred in parallel in pyroloids and monotropoids and that the arbutoid and ericoid mycorrhizal types were each derived from the arbuscular type in Ericaceae.