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 tract, fever, infections, colds, flu, rheumatism and gout. Fresh fruit are usually unpalatable, but they can be debittered and made into compote, jelly, jam, a tangy syrup, a tart chutney, or juice, as well as wine and liqueur, or used for tea or to make flour. Fruit are served as a side dish to lamb or game. Debittering can be accomplished by freezing, cooking, or drying, which degrades the parasorbic acid. The fruit are red colored in August but usually only harvested in October after the first frost by cutting the corymbs. The robust qualities of "S. aucuparia" make it