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
Sorbus mougeotii which differs only in slightly broader leaves. It is also closely related to "Sorbus intermedia" (Swedish whitebeam), which differs in having the leaves grey-white below and more deeply lobed, with the lobes spreading rather than forward-pointing, the fruit oval and less bright red, and in forming a stouter tree with a single trunk and more horizontal branching. All are tetraploid apomictic species which breed true without pollination, and ultimately of hybrid origin between "Sorbus aria" and "Sorbus aucuparia". It is widely grown as an ornamental tree in northern Europe, though usually unrecognised, misidentified as "Sorbus intermedia". Although described in 1858,