POWELL, E. ANN* and KATHLEEN A. KRON. Department of Biology, Wake Forest University, Winston-Salem, NC 27109-7325. - Hawaiian blueberries and their relatives - A phylogenetic analysis of Vaccinium L. sections Macropelma (Klotzsch) Hooker f., Myrtillus Dumortier, and Hemimyrtillus Sleumer.
Phylogenetic relationships among Vaccinium sections
Macropelma, Myrtillus and Hemimyrtillus have been
the subject of much debate but hypotheses about evolutionary
relationships among these taxa have not been tested using a cladistic
framework. 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 there has been disagreement
as to their species content. Vaccinium sect. Macropelma
as currently recognized includes four species: Vaccinium
dentatum, V. calycinum, and V. reticulatum from the
Hawaiian Archipelago and V. cereum from southern Polynesia.
While most investigators agree that the Hawaiian taxa represent a
natural group, the phylogenetic position of V. cereum has been
the subject of much discussion. Some authors place V. cereum in
sect. Macropelma, while others feel that it is closer to other
Pacific sections of Vaccinium (i.e., sect. Bracteata).
The goals of this study were to use molecular data in a phylogenetic
analysis to assess the monophyly of sections Macropelma,
Myrtillus and Hemimyrtillus and to determine their
phylogenetic position in tribe Vaccinieae. Molecular data from the
chloroplast genes matK and ndhF and nrITS for
approximately 50 species of Vaccinieae and three outgroups from
"Andromedeae" were analyzed, individually and in
combination, using parsimony. Results show that both sect.
Myrtillus and sect. Hemimyrtillus are paraphyletic.
Hawaiian representatives from sect. Macropelma form a
well-supported clade derived from within sect. Myrtillus.
However, the Polynesian V. cereum may be of hybrid origin. The
Macropelma + Myrtillus clade is sister to a clade which
contains V. erythrocarpon (sect. Oxycoccoides) sister to
the two Asian representatives from sect. Hemimyrtillus, V.
hirtum and V. smallii. The three Mediterranean taxa from
sect. Hemimyrtillus form a clade weakly supported as sister to
the rest of tribe Vaccinieae.
Key words: Ericaceae, Hawaiian blueberries, Macropelma, Myrtillus, Vaccinieae, Vaccinium