OF А CAMBRIDGESHIRE WOODLAND. 367 
latter society Mercurialis perennis is much more mixed with other forms. 
Primula elatior is abundant. 
Other prominent species are :— 
Viola Riviniana ...... 2-а Orchis mascula...... о 
V. sylvestris... О Habenaria virescens | 
V. hirta ... ss MEE Listera ovata ...... о 
Hypericum hirsutum ... lo _, less than in 
(теит urbanum 0 Scilla nonseripta ... 1 the above. 
Fragaria vesca а Paris quadrifolia... о 
LEpilobium montanum о Arum maculatum .. o 
Adretium nemorosum ..... © Careg sylvatica о 
Nepeta hederacea ........ la Poa trivialis — ...... r 
Ajuga reptans... ..... m Milium effusum ... o 
Locally in this society Deschampsia cespitosa may be mixed with Mercurialis 
perennis: Other plants occurring here are Rubus семих о, Гоха arvensis o, 
Rubus deus vr, and. Epilobium angustifolium * vr. 
Spiræa (тата may also occur here locally in small quantity. This 
Deschampsia cespitosa region forms a direct transition to the Spire Ulmaria- 
Deschampsia сезриоза Society. — It has a slightly higher water-content than 
the typical Mercurialis Society. The percentage of water in the Damp 
Mereulialis Sub-Society seems to be the lowest with whieh Oxlips will 
flourish ; not a single specimen was found in the dry sub-society. 
Mosses are not at all abundant in the Mercurialis Society and never form 
a definite layer. The most abundant are :— 
Fissidens tawifolius.. а. r 
Barbula fallae |... cee о 
Mnium undulatum — .................. а 
DBrachythecium rutabulum |............ а 
Hypnum cupressiforme |... o mostly on trees. 
H. molluscum а o 
A fourth plant society can be recognised on the calcareous clay, which, 
though not extensive, is fairly distinct. In many ways it forms a transition 
between the Spiræa Societies on the one hand and the Mercurialis Society 
on the other. 
IV. Fragaria vesca Society. 
The average summer water-content under moderate conditions of shade is 
about 30 per cent. The light conditions are very much the same as in the 
* Not previously recorded for the county, Babington, 1860; Watson, 1883. 
