A third species of Tessmannianthus (Melastomataceae: Merianieae) from Panama

Tessmannianthus cereifolius, a new species from eastern Panama, is described, illustrated, and compared to its closest presumed relative,T. heterostemon of Ecuador and Peru. The new species is distinguished by its truncate calyx, absence of exterior calyx teeth, and complete glabrosity. A 5-celled ovary is reported for the first time inT. cereifolius andT. heterostemon. The latter was previously thought to be characterized by a trilocular ovary. A distribution map and a revised key to the three Panamanian species ofTessmannianthus are also provided.