Chromosome counts in <Emphasis Type="Italic">Chaetogastra</Emphasis> (Melastomataceae,Melastomateae)

Chaetogastra is the largest genus in Melastomateae, with about 165–190 species. The genus was only recently resurrected, based on species that have been traditionally treated in Tibouchina sects. Diotanthera, Pseudopterolepis, Purpurella and Simplicicaules. This article presents 15 chromosome counts for the genus, a review of the available counts and also a discussion of these counts in a systematic context. Although the sampling in the genus is still poor, the data found in the literature and in our research indicate x=9 as the base chromosome number for the genus. We also found that euploidy may be common in Chaetogastra, with diploid, tetraploid and hexaploid species. Basic chromosome numbers also seem to be a taxonomic character that distinguishes Chaetogastra (x=9) from Brachyotum (x=10).