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 and the cut-leaved whitebeam which is in turn a rowan/Arran whitebeam hybrid. Only two specimens of the Catacol whitebeam are known, making it the rarest tree not only in Scotland, it is tied rarest in the world with Wood's cycad, both with only one specimen alive. A third was recorded as a sapling but is believed to have been destroyed by deer. A seedling has also been grown in Edinburgh.
The latest evaluation by IUCN fails to find one of the 2 trees found, so they state that only 1 tree is left.
The discovery followed work in the 1990s by Scottish Natural Heritage, Dougarie Estate and Royal Botanic Garden Edinburgh. The trees were confirmed as a distinct species by DNA testing.
Graeme Walker of SNH has said:
"These are unique trees which are native to Arran and not found anywhere else in the world, we knew about the Arran whitebeam and the cut-leaved Arran whitebeam, which are also crosses between rowan and different species of whitebeam, but it has been really exciting to discover a completely new species. It is very complex picture but we think that the Arran whitebeams are gradually evolving towards a new type of tree which will probably look very similar to a rowan."

Dr. Ashley Robertson of Bristol University, who helped discover the species, said: "It is not an evolutionary dead end. It is evolution in action".
The new species is the third endemic whitebeam found on Arran and combines the red berries of a rowan with the oval leaves of a whitebeam. The trees are currently within a deer fence which will be extended - delivery of materials by helicopter will be necessary due to the remoteness of the location. The species is named after Glen Catacol where it was found and the only known remaining tree may be over 50 years old.