Sub-associations of Gh-mmcl Vegetation V27 



species Rosa mollis and B. tomentosa occm-, but are rather 

 rare. 



In the drier parts of the woods the sloe or blackthorn 

 (Prunus spinosa) and the hawthorn {Cratmgus monogyna 

 = C. Oxyacantha) are characteristic, and on the outskirts 

 and in open places the broom {Cytisus scoparius) and 

 gorse (Ulex europseus at lower levels and JJ. Gallii at 

 higher) are locally abundant. 



The ground vegetation, as in most types of wood, is 



very variable from place to place. Three 



vee-etatlon ground sub-associations may, however, be 



recognised, though transitions between them 



are numerous. 



1. The sub-association of damp situations with well- 

 aerated soil and mild humus. This possesses a fairly 

 rich flora containing many species with more or less 

 conspicuous flowers. 



2. The sub-association of drier situations with less 

 humus, characterised by a poorer and more uniform flora 

 (Plate IX a). 



3. The sub-association of acid peaty humus charac- 

 terised by a heathy flora (Plate IX b). 



It will be seen that the habitats of these three sub- 

 associations correspond fairly closely with those of the 

 woodland associations of the formation of clays and loams, 

 the formation of sandy soils and the heath formation, 

 i.e. to the damp oakwood, the dry oakwood and the oak- 

 birch heath respectively, and the Usts of species (pp. 81, 

 93, 101, 128) emphasise this correspondence. Neverthe- 

 less it is held that the common characters of the habitat, 

 which presumably determine the general dominance of 

 Quercus sessiliflora throughout the three types of sub- 

 association, are sufficiently marked to consider the whole 

 of this vegetation and the related type of pasture or 

 grassland as belonging to a single formation. 



The following is a list of the more characteristic 



