Phylogenetic relationships among Vaccinium sections Macropelma, Myrtillus, and Hemimyrtillus have been the subject of much debate. These taxa have been proposed as close relatives and they share, along with sect. Oxycoccoides, the character of buds covered by two partially fused prophylls. However, the monophyly of these sections has not been assessed and hypotheses about evolutionary relationships have not been tested using a cladistic framework. While most investigators agree that the Hawaiian taxa from sect. Macropelma represent a monophyletic group, the phylogenetic position of the Polynesian V. cereum has been the subject of much discussion. Molecular data from the nrITS and the chloroplast genes matK and ndhF for 52 species of Vaccinieae were used in a phylogenetic analysis to assess the monophyly of these sections and to determine their phylogenetic position in tribe Vaccinieae. Hawaiian representatives from sect. Macropelma form a monophyletic group that is derived from within sect. Myrtillus. However, the Polynesian V. cereum is likely of hybrid origin. The Myrtillus Macropelma clade is sister to a clade that includes sections Oxycoccoides and Praestantia, and the two Asian representatives from sect. Hemimyrtillus. The Tethyan clade from sect. Hemimyrtillus is sister to the rest of tribe Vaccinieae.
Communicating Editor: Aaron Liston