138 F. E. Fritsch and E. J. Salisbury. 
DESCRIPTION OF PLATE I. 
Phot. 1 . Seedling of Pinus sylvestris in exposed situation. The main 
axis has been bitten off by rabbits, whilst the laterals have developed 
horizontally. 
Phot. 2. Plant of Calluna showing combined effect of nibbling and 
exposure. 
Phot. 3. Two plants of Calluna killed by a fire, showing the superficial 
position of the crowns. The ground-level is indicated by a black line. 
Phot. 4. A plant of Calluna which has sprouted after burning, showing 
the buried crown. 
Phot. 5. An aerial cushion of Ulex nanus. 
Phot. 6. Cushion of U. europaus showing combined effect of nibbling and 
wind-trimming. 
Phot. 7. Two shoots of U. europaus, (A) from a sheltered and (B) from 
an exposed situation. 
LITERATURE 
1. Elgee, Frank. “The Moorlands of North-Eastern Yorkshire, their 
Natural History and Origin.” London (Brown & 
Sons), 1912. 
2. ,, “ The Vegetation of the Eastern Moorlands of Yorkshire.” 
Journ. of Ecol., II, 1914, p. 1. 
3. Fritsch, F. E., and Parker, W. ‘‘The Heath Association on Hindhead 
Common.” Nkw Phytologist, XII, 1913, p. 148 
et seq. 
4. Graebner, P. ‘‘Die Heide Norddeutschlands,” etc., in A. Engler u. 
O. Drude, ‘‘ Die Vegetation der Erde.” Leipzig (W. 
Engelmann), 1901. 
5. Moss, C. E. “The Vegetation of the Peak District.” London (Camb. 
Univ. Press), 1913. 
6. Tanslev, A. G. “Types of British Vegetation.” London (Camb. Univ. 
Press), 1911. 
7. Warming, E. “ CEcology of Plants.” (Engl, transl. by P. Groom.) 
Oxford (Clarendon Press), 1909. 
