KRON, KATHLEEN A.*, E. ANN POWELL, AND JAMES L. LUTEYN. Department of Biology, Wake Forest University, Winston-Salem, NC 27109-7325; New York Botanical Garden, Bronx, NY 10458-5126. - Molecular systematics of Macleania and Psammisia and their relationship to other members of Vaccinieae.
Macleania and Psammisia are two genera of blueberries
found primarily at higher elevations throughout the Neotropical
cordillera. These genera have been considered closely related to each
other and distinct from other tropical Vaccinieae based on features of
the androecium. As part of a revision of these taxa, a molecular
systematic study was performed using nuclear ribosomal internal
transcribed spacer (nrITS) and the chloroplast gene matK for 29
species of Macleania and Psammisia (i.e., about 30% of
the taxa currently recognized within the genera) and selected
Vaccinieae. Analyses of the combined data indicate that most of the
taxa currently within Macleania and Psammisa form a
clade. (Exceptions to this are Macleania megabracteata and
Psammisia urichiana which consistently fall outside the group.)
However, branch lengths are very short at the base of this clade and
therefore bootstrap support for the group is below 50%.
Macleania and Psammisia are both paraphyletic in this
study. The results indicate that Macleania is, for the most
part, derived from within Psammisia. Psammisia
dolichipoda and Ps. sodiroi are indicated as sister and
this relationship has strong bootstrap support. These two species
represent the "globosa" subgroup within Psammisia.
However, the results of this study do not support any of the other
species groups suggested in previous studies for either
Macleania or Psammisia. This study suggests that
Macleania and Psammisia are closely related but that
neither is monophyletic as currently recognized. Further resolution
of species relationships is likely to require a more variable data
source. Larger scale analyses based on combined analysis of
matK, ITS and the chloroplast trnT-L spacer indicate
that Macleania and Psammisia fall within a large clade
that includes other Neotropical genera such as Satyria and
Sphyrospermum.
Key words: blueberries, Macleania, molecular systematics, Neotropical, Psammisia, Vaccinieae