Haptanthus is a monotypic genus containing the sole species Haptanthus hazlettii, a shrub or small tree known only from the locality of Matarras in the Arizona Municipality in Honduras. Its flowers are unique among the flowering plants. A single "female" (carpellate) flower has two branches on either side which carry "male" (staminate) flowers. The flowers are very simple, lacking obvious sepals or petals. The family placement of the genus has been uncertain, but based on molecular phylogenetic research, it is included in the family Buxaceae as of September 2014. Very few individuals have ever been found and its habitat is threatened by logging.