Arran whitebeams

[4][5] The oldest preserved specimen is from the bastard mountain ash, S. pseudofennica, collected in 1797 from North Arran and another of the same species is in the British Museum dated 1838, when it was known as Pyrus pinnatifida (the pear group).

The Scottish mountain ash, S. arranensis, evoked most collecting interest in 1870–1890 and 1920–1940, although older herbarium specimens exist.

Although actual numbers haven't dropped since the first quantitative survey was carried out in 1897, this may be a false impression, since with more searching more have been found, which does not necessarily suggest a stable population.

Grazing by sheep has probably reduced the population from being widespread and numerous to what it is now, confined to steep slopes, cracks in rocks, and restricted to the mountainous northern end of the island.

[citation needed] The Ranger's Service have taken steps to increase the distribution of the trees, planting both species in the park.

[9] In 2007 it was announced that two specimens of the newly named Catacol whitebeam (Sorbus pseudomeinichii)[10] had been discovered by researchers on Arran.

The tree is again a cross between the native rowan and whitebeam, the discovery being made following work by Scottish Natural Heritage (SNH), Dougarie Estate and Royal Botanic Garden Edinburgh.

A team from the Royal Botanic Gardens collected seeds and cuttings to ensure the long-term survival of the trees and steps were taken to protect the two known specimens.