Arran whitebeams complex fashion, which involved the common whitebeam ("Sorbus aria") giving rise to the tetraploid rock whitebeam ("Sorbus rupicola") which is still found on Holy Isle. This species is able to survive at higher altitudes and therefore occupies a less competitive niche with fewer tree species able to tolerate the harsher conditions. The rock whitebeam interbred with the rowan / mountain ash ("Sorbus aucuparia") to produce the hybrid, a fertile separate species the Scottish whitebeam ("Sorbus arranesis") which grows well in this zone of reduced competitive growth at higher altitudes. The bastard mountain ash ("Sorbus pseudofennica") arose from a further cross
Sorbus not closely related to the true ash trees which belong to the genus "Fraxinus", although the leaves are superficially similar. As treated in its broad sense, the genus is divided into two main and three or four small subgenera (with more recent generic assignments in parentheses): "Sorbus" species are used as food plants by the larvae of some moth species—see list of Lepidoptera that feed on "Sorbus". "Sorbus domestica" is used to flavour some apple wines, see "Apfelwein. "Sorbus" species are cultivated as ornamental trees for parks and gardens, and have given rise to several cultivars. The following, of mixed