These trees are the Scottish or Arran whitebeam ( Sorbus arranensis ) , the bastard mountain ash or cut - leaved whitebeam ( Sorbus pseudofennica ) and the Catacol whitebeam ( Sorbus pseudomeinichii ) .
The island has three endemic species of tree , the Arran whitebeams .
These trees are the Scottish or Arran whitebeams   ( Sorbus arranensis ) , the bastard Arran whitebeams   or cut - leaved whitebeam ( Sorbus pseudofennica ) and the Catacol whitebeam ( Sorbus pseudomeinichii ) .
The island has three endemic species of tree , the Arran whitebeams .