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 include 'Apricot Queen', 'Brilliant Yellow', 'Chamois Glow', 'Pink Queen', and 'Salmon Queen'. The leaves were fermented with leaves of sweet gale and oak bark to create herb beer. Fruit are eaten as a mash in small amounts against lack of appetite or an upset stomach and stimulate production of gastric acid. In folk medicine they are used as a laxative, against rheumatism and kidney disease, and as a gargled juice against hoarseness. Wood of "S. aucuparia" is used for cartwright's work, turner's work, and woodcarving. Wood can be used from trees as young as 20 years. The sapwood is golden