IIT] SCRUB ASSOCIATIONS 99 
be placed in the same plant formation as the ash woods. 
There is, so far as one can judge, little or no essential change 
in the essential nature of the habitats of the various woods and 
their related scrub; and intermediate examples are so very 
numerous and varied that it would seem to be quite impossible 
to decide on any natural line of demarcation between woodland 
and related scrub. 
In subordinate associations such as these, which are “on 
the move,” 2.e., which are kinetic and not static, it is a difficult 
matter to give really satisfactory lists of plants. If the 
localities are not very carefully chosen, one finds, in the case of 
scrub, for example, that one takes a list of species almost 
characteristic of a wood or a list almost characteristic of grass- 
land. The following lists, however, are taken from typical 
cases of scrub, though another observer might easily include 
either more woodland species or more grassland species. As it 
is, it will be seen there are very few species of the scrub which 
do not occur either in the woodland or grassland associations ; 
and from this point of view alone, it is not possible to regard 
the different types of scrub that occur in this district as consti- 
tuting a natural group of plant communities. 
Scrub on 
sandctnne asain on biti on 
plateaux 1 aly sere 
and slopes slopes slopes 
Trees, shrubs, and undershrubs 
Salix caprea r 
S. caprea x cinerea vr 
S. cinerea ) 
var. aquatica r 
var. Oleifolia 1s 
S. aurita ) 
S. aurita x caprea r 
S. aurita x cinerea r 
S. repens vr 
Corylus Avellana r 
Betula pubescens r to a 
var. parviflora r 
forma denudata ) 
Quercus sessiliflora r to o 
Pyrus Malus r to o 
P, Aucuparia ty) 
