Petersianthus is a genus of woody plant in the Lecythidaceae family first described as a genus in 1865 under the name Petersia. This turned out to be an illegitimate homonym, meaning that it had already been used by someone else to refer to a very different plant. So the name of these species in the Lecythidaceae was changed to Petersianthus. It is native to the Philippines and to parts of Africa.