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 (Possibly only one is alive), 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. 
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 (after the Arran whitebeam and the cut-leaved whitebeam) 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.
- "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17. Cite uses deprecated parameter
- Johnston, Ian (15 June 2007) Trees on Arran 'are a whole new species'. Edinburgh. The Scotsman newspaper Retrieved 18 June 2007.
- "New species of tree discovered on Arran". 2007-06-14. Retrieved 2007-06-17.
- Revealed, the New Species of Tree With Scottish Roots Retrieved 18 June 2007.
- New species of tree discovered bbc.co.uk Thursday, 14 June 2007 (Accessed June 18, 2007)