The No Parking Whitebeam (Sorbus admonitor) or Sorbus No Parking is a species of whitebeam tree found in Devon, United Kingdom. Its unusual name derives from the location of the first tree to be found (not the type specimen) – by a lay-by near Watersmeet in North Devon, with a "no parking" sign nailed to the tree. Although first recognised as a distinct variety in the 1930s (by the botanist E. F. Warburg) because of its strongly lobed leaves, it was only accorded species status in 2009, after various biochemical analyses. It is believed at least 110 individuals of the species exist. The leaves of the No Parking Whitebeam have more accentuated lobes than the Devon Whitebeam, of which it was thought before to be a variety.
The research project that named the tree as a species was led by Dr Tim Rich, head of vascular plants at the National Museum Wales, as well as academics from Bristol University, Exeter University, Oxford University and the Royal Botanic Gardens, Kew. The announcement of the species, and of thirteen other Sorbus species, was made in two papers in the BSBI's journal Watsonia.
It is similar to Sorbus devoniensis, but differing in having leaves more deeply lobed, 10–23% of the way to the midrib at the centre of the lamina – not 6–18% as in S. devoniensis; the leaves of S. admonitor are also glossier than those of S. devoniensis.
It is endemic to the Watersmeet area, where there are at least 108 trees in the East Lyn Valley and two trees nearby above Sillery Sands, Lynmouth. S. devoniensis does not grow in this area. The two species have not been confirmed as growing together.
- "Botanists discover new species of tree growing in a lay-by... and name it No Parking". Daily Mail. 2009-03-05.
- "A species of tree so new it's named after No Parking sign". The Herald (Plymouth). 2009-03-05.
- Palmer, Tom (2009-03-06). "No Parking: a tree by any other name". London: The Independent. Retrieved 2010-05-23.
- T. C. G. Rich & M. C. F. Proctor (2009). "Some new British and Irish Sorbus L. taxa (Rosaceae)". Watsonia. 27: 207–216.
- T. C. G. Rich, S. A. Harris & S. J. Hiscock (2009). "Five new Sorbus (Rosaceae) taxa from the Avon Gorge, England". Watsonia. 27: 217–228.
- "14 new trees discovered in the UK and Ireland". National Museum Wales. 2009-03-06.
- "Tree revealed as something completely different.." Yorkshire Post. 2009-03-06.
- Bailey, J.P.; Kay, Q.O.N.; Mcallister, H.; Rich, T.C.G. (2008). "Chromosome numbers in Sorbus L. (Rosaceae) in the British Isles". Watsonia. 27: 69–72.