Petrobium is a genus in the family Asteraceae.Brown, Robert. 1818. Transactions of the Linnean Society of London 12(1): 113-114 description in Latin, commentary in EnglishTropicos, Petrobium R. Br.
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 plants are either female or hermaphrodite, i.e. the species is gynodioecious.Flann, C (ed) 2009+ Global Compositae Checklist
See also Flora of St Helena
References
External links Mongabay: Petrobium