Petrobium
(from petros, a rock, and bio, to live; alluding to the habitation of the species). SYN. Laxmannia (of Forster). ORD. Compositae. A monotypic genus, the species being an ornamental, stove tree. It thrives in sandy loam, and may be increased by cuttings, which root readily in a similar soil. P. arboreum (tree-like). fl.-heads yellow, dioecious, mediocre or rather small, disposed in corymbose, leafy panicles, at the apices of the branches; involucre campanulate; bracts few; receptacle small, flat; achenes hispidulous, scabrous. June. l. opposite, dentate. St. Helena, 1816.