The only known species is Petrobium arboreum, called Saint Helena whitewood. It is found in the tree-fern thicket at the top of the central ridge of island of Saint Helena in the South Atlantic Ocean.
The only identified species is Petrobium arboreum, which is also called Saint Helena whitewood. It is located in the tree-fern thicket at the peak of the central ridge of Saint Helena island in the South Atlantic Ocean.