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 chamaemespilus in corymbs 3–4 cm diameter. The fruit is an oval red pome 10–13 mm diameter. It is the sole species in a group that has been called genus "Chamaemespilus" or "Sorbus" subgenus "Chamaemespilus", distinguished from other subgenera of "Sorbus" by the pink (not white) flowers with forward-pointing petals (not opening flat). More recently, it has become clear that the simple-leafed species traditionally included in "Sorbus" form a monophyletic group, and this species could be included in a clade called "Aria" (genus "Aria" or "Sorbus" subgenus "Aria"). Sorbus chamaemespilus Sorbus chamaemespilus, the false medlar or dwarf whitebeam, is a species of