90 
W. Watson. 
THE DISTRIBUTION OF BRYOPHYTES IN THE 
WOODLANDS OF SOMERSET. 
By W. Watson. 
T HE county of Somerset has a most interesting flora, the rich¬ 
ness of which is due to a number of causes; prominent 
amongst these are the mild climate, well-wooded character, varia¬ 
bility of rainfall, diversity of physical and geological aspects, and 
last, but not least, the comparative immunity from the smoke of 
manufacturing and thickly populated districts. The geology of the 
county is very complicated, every system from the Old Red Sand¬ 
stone to recent deposits being represented, giving rise to great 
variability in its soils and physical geography, the peat moors and 
alluvial flats of the Sedgemoor area forming a sharp contrast with 
the Carboniferous limestone of the Mendips, whilst the alternation 
of Jurassic clays and limestones give rise to the characteristic 
undulations of the eastern portion. 
The woodlands are well represented by the oak and ash-types. 
In the former the oak is the dominant tree, the ash being confined 
to damp situations. Oak woods, of the character of many of those 
met with on the clays of the south-east of England are seldom 
seen, but the oak-woods of the Upper Greensand of the eastern 
boundary of Somerset are quite comparable with those on the 
sandy soils of other parts of the country. The ash-woods are 
dominated by the ash, the oak occupying a similar subordinate 
position as the ash does in the oak-woods. The woods of the ash- 
type are very variable in character, elimination of the ash and its 
replacement by hazel often giving rise to a derived form of wood¬ 
land, which is well represented in Somerset. These woods have 
been called oak-hazel-woods 1 , the oak and the hazel being the 
dominant woody plants, while ash standards are of infrequent 
occurrence. As these oak-hazel-woods are so characteristic a 
feature of the county I have considered it advisable to retain the 
term for local use, though they have little in common with the oak- 
hazel coppices of the south-east of England, these being undoubtedly 
offshoots from the lowland oak-woods. In some of the woods the 
transition from the ash-type to the oak-hazel form are very striking, 
recurring again and again in the course of a few miles. 
1 C. E. Moss. Geographical Distribution of Vegetation in 
Somerset, Royal Geogr. Soc., 1906. 
