Abstract
Poteranthera (Melastomataceae) is a genus of small, annual herbs with narrow leaves, that inhabit humid savannas in South America and are visible only when in bloom. Due to their size and paucity of collections, the phylogenetic position of Poteranthera has been uncertain to this point. Poteranthera has been at times associated, confused, or placed in Acisanthera and/or Siphanthera. Phylogenetic analyses based on DNA sequence data place Poteranthera unequivocally within the Microlicieae and not closely related to Acisanthera or Siphantera. These results are consistent with seed and anther morphology. Putative morphological synapomorphies for this genus are the glandular hairs restricted to the leaf margins and the apically constricted hypanthium. Based on morphology, Acisanthera leptalea seems better placed in Poteranthera and the new combination Poteranthera leptalea is made. An expanded generic description is also provided.