Although epigyny traditionally has been considered to be derived from hypogyny, recent evidence suggests that ovary position is more dynamic than this longstanding view of unidirectional change indicates. Melastomataceae show a complete range of ovary positions and are an ideal family in which to study ovary diversification in a phylogenetic context. Parsimony analysis of ITS sequence data for 33 species among 18 genera in Miconieae, Merianieae, and Blakeae indicates that these three tribes form a well-supported monophyletic group with Merianthera as sister to a large well-supported clade that is a polytomy with five branches. In this polytomy: most Miconieae form one poorly resolved clade; three genera of Miconieae (Bellucia, Henriettea, and Henriettella) and two genera of Blakeae (Blakea and Topobea) form two well-supported clades; and three genera of Merianieae make up the two remaining branches of the polytomy. It is noteworthy that Merianthera is sister to all other genera because it is the only Merianieae with an inferior ovary: all remaining members of the tribe exhibit superior ovaries. Initial mapping onto our shortest trees of published reports of ovary positions reveals that: the outgroup genera all have superior ovaries; Merianthera, with an inferior ovary, is the first-branching member of the ingroup; and the large sister clade comprises members with a complete range of ovary positions, with many intermediates. Although further character analysis is needed, diversification of ovary position within these melastomes may be dynamic and contradictory to the traditional view of unidirectional change from superior to inferior ovary position.

Key words: ITS phylogeny,Melastomataceae,ovary diversification