Sorbus arranensis rupicola") which is still found on Holy Isle. This hybrid species interbred with the rowan/mountain ash ("Sorbus aucuparia") to produce "S. arranesis". The bastard mountain ash ("Sorbus pseudofennica") arose from a further cross between "S. arranensis" and the mountain ash ("S. aucuparia"). Smart showed by using physical characteristics that the species were separate and not a result of random variation. Some overlap does however occur and this suggests that some hybridising may occur between the two species. Sorbus arranensis Sorbus arranensis, sometimes referred to as the Scottish or Arran whitebeam is a species of plant in the family Rosaceae. It
Forests of the Iberian Peninsula form small enclaves or copses at the foot of rocky cliff edges or in the clearings of beech forests, on poor or acidic soils, accompanied by aspen ("Populus tremula") and mountain ash ("Sorbus aucuparia"). Birch may also grow in pure stands near the beech forests, in the mountainous areas on siliceous bedrock; these areas are typically of only small extent and generally quite patchy with sessile oak ("Quercus petraea") and trees of the genus "Sorbus". The silver fir ("Abies alba") is found on the cool, deep-soiled slopes of the flanks of the Pyrenees, from Navarre to Montseny, forming pure fir