KRON, KATHLEEN A.* and E. ANN POWELL. Department of Biology, Wake Forest University, Winston-Salem, NC 27109-7325. - Phylogenetic relationships within the blueberry tribe (Vaccinieae, Ericaceae) based on matK and nrITS sequence data.
The blueberry tribe is a large and morphologically diverse group that
is widespread in the temperate and tropical zones of most continents.
It is morphologically distinct from remaining members of Ericaceae
s.l. in its possession of an inferior ovary. Among the approximately
40 genera described within Vaccinieae, Vaccinium is the largest
and most widespread, occurring in both the Old and New World temperate
and tropical latitudes. In the Neotropics 30–35 genera are recognized
compared to only four or five recognized genera in the Old World
tropics. This study sampled 93 species of Vaccinieae, representing 30
genera, and 17 sections (of the approximately 33 currently recognized)
of Vaccinium. For each species, sequence data from the
chloroplast matK gene and the nrITS were obtained. Each data
set was analyzed separately and then as a combined matrix. Strict
consensus trees generated from the individual data analyses did not
indicate any strongly supported conflicting relationships. In the
strict consensus of the combined analysis seven clades (most weakly
supported) form a polytomy at the base of the tree. However, several
well supported (bootstrap) clades (provisionally named for discussion
purposes only) were found. These include: an Andean clade composed of
representatives of 19 of the 23 Neotropical genera sampled (excluding
Vaccinium), a Meso-American/Caribbean clade, a Malesian clade
including the Old World taxa Paphia and Dimorphanthera,
an Agapetes clade comprised of some Asian Vaccinium and
Agapetes, and a Bracteata-Oarianthe clade
(Vaccinium spp.). These results indicate that Vaccinium
is not monophyletic and suggest that Vaccinium represents a
grade group out of which several tropical groups have evolved. This
study also indicates that several other genera currently recognized in
Vaccinieae are likely not monophyletic. These include the Old World
genera Dimorphanthera, Paphia, and Agapetes, and
the Neotropical genera Diogenesia, Orthaea,
Thibaudia, Sphyrospermum, and Disterigma.
Key words: Ericaceae, molecular systematics, tropical blueberries, Vaccineae, Vaccinium