52 
The Vegetation of Somerset. 
Woodlands. Of natural woodlands within the wheat area Mr. 
Moss recognises three main types, the oak, the oak-hazel, and the 
ash woods. The ash-woods are found on the slopes of limestone hills, 
fringing the summit-cultivation of the Mendips and also on the 
carboniferous limestone, on dolomitic conglomerata and on oolites. 
In these woods the Oak is merely a secondary species. The Yew 
and the White Beam, Dog’s mercury and Wood garlic are 
characteristic of the ground-vegetation, while Bluebells and Bracken 
are scarce. This type of woodland is also well developed on the 
Derbyshire limestones. 
The oak woods in Yorkshire have been divided into upland or 
dry and lowland or damp oak woods, characterised respectively by 
Quercus sessilifiora and Q. pednnculata , and with characteristically 
distinct ground floras. The same division can be made in Somerset, 
but the latter type is by far the more extensive, and the scale does not 
allow of this distinction being indicated on the map. The oak- 
hazel wood is a type very familiar to the southern botanist, and is 
now for the first time recognised on a vegetation map. “The oak 
is the dominant tree, but in these woods it is not planted so thickly 
as in the oak woods of the sandstones. Shrubs, usually hazel, are 
planted thickly among the oak standards .... Many of these woods 
are about a century-and-a-half old, but others are more ancient, 
and possess many of the characteristics of primitive woodland.” 
This kind of woodland occurs in Somerset on deep marls and clays. 
The ground flora is markedly different from that of the oak woods 
and has much in common with that of the ash woods. Mr. Moss 
gives a very useful analytical table showing the presence and relative 
abundance of a great number of woodland species, from which it 
appears that while both oak and ash, and ash and oak-hazel have 
many species common to the two and absent from the third type, 
there are scarcely any species found in the oak and oak-hazel and 
absent from the ash-type. This is apparently due to the presence 
of much humus in the oak woods and its comparative scarcity in 
the other two types. To what factors the common features of oak 
and ash woods are due is not quite clear. It will be of great 
interest to see how far Mr. Moss’s results for woodlands are 
confirmed in other southern districts. 
“Natural pasture” and “limestone heath” cover considerable 
tracts on the limestone of the Mendips. The latter association has 
Calluna and Erica cinerea growing mixed with ordinary limestone 
plants whenever the soil reaches a depth of three inches or more. 
In Derbyshire the heath plants are actually dominant on limestone 
over considerable areas. The determination of the critical factors 
involved here should be quite possible and would be of great 
interest. We have no space to consider the many other interesting 
features of Somerset vegetation, such as the development of the 
maritime associations, brought out by Mr. Moss. His paper is an 
admirable specimen of survey work performed by a botanist who 
knows his flora very thoroughly and has a masterly grip of the 
principles of the subject. It is in some respects a considerable 
advance on the preceding memoirs in this series. The map is 
excellently reproduced by the Royal Geographical Society, to whose 
enlightened and progressive policy in encouraging all branches of 
modern geographical study, British plant-ecology owes a very real 
debt. The paper is illustrated by many “half-tones” representing 
apparently admirable photographs. It would have been well worth 
while to print these as plates on highly glazed paper. At present they 
suffer considerably from being printed on ordinary paper. A.G.T. 
