COMBINED MOLECULAR AND MORPHOLOGICAL PHYLOGENETIC ANALYSES OF THE BLAKEEAE (MELASTOMATACEAE)

摘要

Premise of research. The Blakeeae (Melastomataceae) comprise nearly 200 species in Blakea and Topobea and another 10 species in Chalybea and Huilaea. The former two genera have been separated primarily on the basis of characters pertaining to anther morphology. Combined molecular and morphological phylogenetic analyses were conducted to evaluate generic limits, reconstruct patterns of morphological character evolution, and identify clades within the tribe. Methodology. To test the monophyly of Blakea and Topobea, we analyzed 111 morphological characters, nuclear ribosomal internal transcribed spacer region, the accD-psal and atpB-rbcL spacer regions, and trnL-trnF nucleotide sequence data, using maximum likelihood and parsimony in individual and variously combined data sets comprising up to 3955 characters and 135 terminals. Pivotal results. Chalybea and Huilaea were recovered as a clade sister to the clade of Blakea and Topobea. Neither of the latter two genera was resolved as being monophyletic in any analysis, nor does anther morphology support their separation. Five infrageneric groupings were discovered, and their synapomorphic morphological characters and natural history are discussed. Conclusions. We present the first phylogenetic analysis of the Blakeeae, using combined molecular and morphological characters. Topobea must be transferred to Blakea. Within Blakea, a single shift from bee to vertebrate pollination has occurred, and this clade is well defined by morphological synapomorphies, including pseudocampanulate corollas and stomatal nectaries on the anther connectives. Floral mimicry is hypothesized to occur in the Solanum flowered clade.