The genus Sorbus includes a number of closely related whitebeam species which can be recognised by subtle differences in the size of petals, form of the leaves plus the colour, size and shape of the fruits. Many of these "microspecies" are endemic to small areas of Britain. That is to say they are unknown anywhere else in the world!

Exmoor is rich in whitebeams, with Sorbus subcuneata, S. vexans and the recently named S. margaretae (formerly S. "taxon D") being confined to the Exmoor area. There is also the "No Parking tree" which was first found next to a lay-by near Watersmeet with a "No parking" sign affixed to it. It has only recently been named by taxonomists as Sorbus admonitor.

Four other somewhat more widespread species, S. anglica, S. devoniensis, S. porrigentiformis, and S. rupicola also occur in the Exmoor area. The exceptionally localised world distribution of these trees makes their conservation on Exmoor of the utmost importance.

S. anglica, S. subcuneata, S. vexans are all classified as rare species in the British Red Data Book. S. devoniensis, S. porrigentiformis and S. rupicola are somewhat more common but are classified as nationally scarce.

These whitebeams are generally confined to steep rocky, coastal slopes, frequently in association with coastal sessile oak woodland - particularly Culvercliff Woods, Culbone, Watersmeet, Woody Bay and the Heddon Valley. S. devoniensisis the exception, being an inland species, which is found on woodland edges and in hedgebanks in parts of mostly Devon and some areas of Somerset and Cornwall.  

As the whitebeams are often found on the steep rocky slopes you should take care when looking for them. They are also found alongside footpaths so keep an eye out for their distinctive foliage if you are using the extensive public rights of way network of the northern coast.

Exmoor National Park Authority is actively surveying, recording and including these special trees in its woodland management plans and shall be working with its partners to encourage the wider conservation of the species.