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 domestica Sorbus domestica Sorbus domestica, with the common name service tree or sorb tree (because of its fruit), is a species of "Sorbus" native to western, central and southern Europe, northwest Africa (Atlas Mountains), and southwest Asia (east to the Caucasus). It may be called true service tree, to distinguish it from wild service tree "Sorbus torminalis". It is a deciduous tree growing to 15–20 m (rarely to 30 m) tall with a trunk up to 1 m diameter, though it can also be a shrub 2–3 m tall on exposed sites. The bark is brown, smooth on young trees, becoming