Sorbus pseudomeinichii of the location. The species is named after Glen Catacol where it was found and one of the two surviving plants is thought to be more than fifty years old. Sorbus pseudomeinichii Sorbus pseudomeinichii, known as false rowan and Catacol whitebeam, is a rare tree endemic to the Isle of Arran in south west Scotland. It is believed to have arisen as a hybrid of the native rowan ("Sorbus aucuparia") and the cut-leaved whitebeam ("Sorbus pseudofennica") which is in turn a rowan/Arran whitebeam ("Sorbus arranensis") hybrid. Only two specimens of the Catacol whitebeam are known, making it the rarest tree
Sorbus aucuparia in an alternate leaf pattern on a branch., distinguishing them from those of ash, "Fraxinus excelsior", which are opposite and without stipules. The leaflets are elongated-lanceolate in shape, 2 to 6 cm long, and 1 to 2.5 cm wide with a sharply serrated edge, and have short stems or sit close to the central vein except for the outermost leaflet. Leaflets are covered in gray-silvery hairs after sprouting but become mostly bare after they unfold. Their uppers side is dark green and their underside is a grayish green and felted. Young leaflets smell like marzipan when brayed. The leaflets are