CLAUSING, GUDRUN* AND SUSANNE S. RENNER. Institut fuer Spezielle Botanik, University of Mainz, D-55099 Mainz; Department of Biology, University of Missouri-St. Louis, MO 63121. - Phylogenetic relationships and character evolution in Melastomataceae.
Melastomataceae are a tropical eudicot family of about 156 genera and
4500 species. Melastome androecium and fruit evolution are little
understood due to controversial hypotheses about family
circumscription and intra-family relationships. Our poster presents a
phylogenetic hypothesis for Melastomataceae and their closest
relatives, Memecylaceae, Crypteroniaceae, Alzateaceae,
Rhynchocalycaceae, Oliniaceae, and Penaeaceae, based on combined rbcL,
ndhF, and rpl16 sequences and parsimony, minimum evolution, and
maximum likelihood reconstructions. Fifty-six exemplars, representing
the 13 traditional tribes and three subfamilies, Astronioideae,
Melastomatoideae, and Memecyloideae (= Memecylaceae DC.), were
sequenced, with additional denser taxon sampling for ndhF.
Memecylaceae are sister to Melastomataceae, and Pternandra, a SE Asian
genus of 15 species, is the first-branching Melastomataceae. This
placement of Pternandra has low bootstrap support (72%), but agrees
with its melastome-like leaf venation. The next deepest split is
between the SE Asian Astronieae, with anthers opening by slits, and
the remaining melastomes, which have anthers opening by pores.
Morphological implications of the phylogeny concern stamen connective
appendages, loss of anther endothecia, the evolution of poricidal
dehiscence, and switches between berries and capsules.
Key words: Alzateaceae, Crypteroniaceae, Melastomataceae, Memecylaceae, Oliniaceae, Rhynchocalycaceae