Sorbus pseudomeinichii 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 in Scotland and also the United Kingdom. A third was recorded as a sapling but is believed to have been destroyed by deer. A seedling has also been grown in
Sorbus alnifolia Sorbus alnifolia Sorbus alnifolia (syn. "Aria alnifolia"), also called alder-leafed whitebeam, Korean whitebeam, or Korean mountain ash, , is a species of whitebeam native to eastern Asia in eastern and northern China, Taiwan, Korea and Japan. "Sorbus alnifolia" is a medium-sized deciduous tree growing to 10–20 m tall with a trunk up to 30 cm diameter and grey bark; the crown is columnar or conic in young trees, becoming rounded with age, with branches angled upwards, and slender shoots. The leaves are green above, and thinly hairy with white hairs beneath, 5–10 cm long and 3–6 cm broad, simple, usually