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 aucuparia and white, while the heart-wood is brown. In almost treeless regions it is used as firewood. The leaves are sometimes used as fodder for livestock while the fruit are used against erysipeloid infections in domestic pigs and goats. Bark of the plant was used to dye wool brown or red. Honey from "S. aucuparia" flowers is strongly aromatic and has a reddish color. "Sorbus aucuparia" is planted in mountain ranges to fortify landslides and avalanche zones. It is also used as an ornamental plant in parks, gardens, or as an avenue tree. Ornamental cultivars include 'Asplenifolia', which has divided and