OF А CAMBRIDGESHIRE WOODLAND, 2025 
its extreme form this sub-society is very distinct. Rubus, mainly А. estis, 
may form such a dense tangle of shoots as practically to exclude all other 
species except a few spring flowers, such ах Viola Riviniana, Orchis mascula, 
Primula elatior, which, however, are not numerous. This tangle of Rubus 
shoots іх usually mixed with some other woody plants, as Kosa arvensis, 
R. dumalis, №. lutetiana, and other species of Rubus and Nosa. Mixed with 
these ате some Spirea Ulmaria and such tall plants ах Cnicus palustris, 
Angelica sylvestris, and Epilobium хр. Other plants occurring here аге: 
Vicia sepium... 0, Lathyrus pratensis... o, La. sylvestris ... УГ, 
which climb over the tangled shoots. This is the extreme case of this 
Society. At other times it passes gradually into the Spirea Ulmaria 
Society on the increase of shade and moisture; or to the буга Ülmaria- 
Deschampsia ewspitosa Society, by the coming in of Deschampsia caspitosa 
in greater quantity with the associated plants noted above. 
Spiræa Ulmaria and Rumex viridis Sub-Society. 
In one part of the wood a local variation or sub-society occurs. Near the 
edge of the wood a Spirwa Ulnaria- Deschampsia caspitosu Society undergoes 
а change by the diminution of the grass and the appearance of Rumew viridis 
in very large quantity with бра Ulmaria. Associated with these are, 
among others :— 
Campanula Trachelium с. 0-i 
Epilobium parviflorum л. О 
FE. montanum eee о-а 
ЈМ. tetragonum ...... esee lo 
Poa trivialis ||... о 
Anthoxanthum odoratum а. о 
Carduus erispus «sess lo 
This sub-society is of very limited extent, and, perhaps, not much more 
than а Rumex community * in the other society. 
These various societies with Spirea Ulmaria cover more than three-fourths 
of the calcareous clay area of the wood. The rest of this region is covered 
һу two main types of ground flora 
the one dominated by Mercurialis 
verennis; and a mixed transition type which may be referred to as the 
1 А 
Fragaria vesca Society, as that is the most abundant species in most parts 
of it. 
ПІ. Mercurialis perennis Society. 
This is in sharp contrast to those previously described. Apart from other 
factors, the water-content is strikingly different. 
* Clements, 1905, p. 297. 
