Metopium, commonly known as poisonwood, is a small genus of dioecious flowering trees in the family Anacardiaceae (the sumac or cashew family), placed in the order Sapindales. The genus is native to the Caribbean region and adjacent parts of Central America and southern Florida.
All members of the genus produce a highly caustic resinous sap that causes severe contact dermatitis in humans, placing them among the more notorious toxic plants of the region. This toxicity is characteristic of many Anacardiaceae, which also includes well-known irritants such as poison ivy and poison oak.
The genus comprises a small number of species — Plants of the World Online recognised four as of 2021: Metopium toxiferum (Florida poisonwood), native to southern Florida and the Bahamas; Metopium brownei (black poisonwood), found across Mesoamerica and the Caribbean; Metopium venosum (Cuban poisonwood); and Metopium gentlei. As dioecious trees, individual plants are either male or female, with flowers on separate individuals.
Distribution
Metopium is distributed across the Caribbean basin, Mesoamerica, and the southern tip of Florida. Metopium toxiferum occurs in southern Florida and the Bahamas; Metopium brownei ranges through Central America and the Caribbean; and Metopium venosum is recorded from Cuba.
Ecology
Members of Metopium are dioecious trees (separate male and female individuals) that produce a highly toxic, resinous sap. Contact with bark, leaves, or sap causes severe contact dermatitis in most people, analogous to the reaction caused by relatives such as poison ivy (Toxicodendron).
Taxonomy Notes
Metopium is placed in the family Anacardiaceae, order Sapindales. Plants of the World Online recognised four accepted species as of August 2021. The GBIF backbone records two species. The genus name is used for poisonwood trees of the Caribbean and Central America; it should not be confused with any other use of the name.
