White. Cassell, 2003 has even greater coverage but suffers from the same drawback -
no definitive species keys. The Collins Complete British Trees by Paul Stcrry 2007
has good descriptions, both leaf and twig keys, and superb photographs of leaves, fruit
and habit, - but again no keys down to species. Similarly, Trees. A field guide to trees
of Britain and Northern Europe. White, White & Walters. Oxford, 2005 does not
have keys to species, leaving the user to wade through the illustrations in the hope of
finding a match. The descriptions although detailed are inconsistent and frustratingly
inadequate to form a positive I.D. in numerous cases. For taxa that occur as natives or
are widespread naturalized aliens, A New Flora of the British Isles by Stace. Edition 2.
CUP, 1975 has good keys and often good illustrations as well. Of the earlier guides, A
Field Guide to the trees of Britain & Northern Europe by Alan Mitchell. William
Collins, 1974 is brilliant with a good range of keys and comparative features. Oleg
Pollunin's Trees and Bushes of Britain and Europe. Paladin, 1974 is also a good
book if you can get hold of it, and is one of the only books covering shrubs. Apart from
Stace, and the incredibly good BSBI Handbook No. 4: Willows and Poplars, by Meikle,
1984. None of these guides give keys down to species level. The biggest problem any
tree book author has is what to include and what to leave out. The 'Oaks of the World'
web-site reckons there are around 550 acceptable species in the genus Quercus; there
are reckoned to be 125 species of Salix in the new world alone, and globally the latest
check-list enumerates 805 taxa of conifers. Almost any of these could have been collected
and planted by somebody if our climate is suitable. Willows. The genus Salix, by
Christopher Newsholme, Batsford, 1992 is pretty close to a world monograph, but it
doesn't have a species key. Unfortunately definitive, comprehensive world monographs
have yet to be produced for most of the tree genera. So we are stuck with purchasing a
range of tree books in the hope that in one or the other enough detail can be gained to
I.D. a non-native tree. The Tree Key. by Herbert Edlin. Frederick Warne, 1978,
presumably meant to complement Francis Rose's Wild Flower Key, again fails to key
taxa down to specific level, and is now long out of print. A very useful inexpensive little
tree book covering 350 species, The Pocket Guide to Trees, by Keith Rushforth. Mitchell
Beazley, revised edition 1995, is still in print and well worth getting as an extra source
of info on alien trees planted in the U.K. All our British tree book authors are put to
shame by the amazing Charles Spargue Sargent who produced a very detailed book,
Manual of the Trees of North America. 1922. Reprint 1965 by Dover Publications
N.Y., of the then known 717 north American Wees, with keys to genera and species, plus
very detailed comparative descriptions, and illustrated by two contemporary artists, as
long ago as 1905 (second edition 1922).
Next time: identifying and recording Ferns, Mosses, Hornworts, Liverworts, and algae.
14
Essex Field Club Newsletter No. 57, September 2008