16 BRITISH PLANTS 
woods, and of evergreen woods there are several types, 
each characterized by a special kind of climate. Thus 
we have the evergreen rain-forests of the Tropics, with 
a climate exceedingly hot and moist; the coniferous 
evergreen forests of Northern Russia, where the climate 
is cold and dry ; and the evergreen dry-woods of Southern 
Europe, where the climate is dry and warm. 
We see from this that the physiognomic groups. into 
which we have divided the vegetation (woodland, grass- 
land, heath, etc.) are only in part associated with 
definite types of climate. A nearer approach to a 
climatic grouping is obtained if we split up the physiog- 
nomic groups into subdivisions founded upon climatic 
differences, thus : 
| 
. ! 
| Physiognomic Divisions. Climatic Subdivisions. 
1. Woodland .. i. Deciduous dicotyledonous woodland. | 
(a) Wet type (oak). 
(b) Dry type (birch). 
ii. Evergreen dicotyledonous woodland. 
(a) Wet type (Tropics). | 
(b) Dry type (Mediterranean). 
iii. Coniferous woodland. 
(a) Cold type (Russia). 
(b) Dry warm type (Mediterranean). | 
Wet moorland (bogs). 
2. Moorland ef pealtit 
( 
| 3. Grassland .. | (a) Wet type (meadows). 
( 
a) 
b) Dry moorland (heaths). 
a) 
b) Dry type (pastures). 
4. Deserts 
In this country the only natural deserts we have are 
sea-beaches and sand-dunes. The desert is an open type 
of habitat, containing many bare spots where plants are 
practically free from competition. Artificial open habi- 
tats are produced in cultivated fields and waste places 
frequently disturbed by man. When the ground is 
fully occupied by plants, the habitat is said to be closed, 
and where this has happened, a stable community of 
plants or associations of plants is established. 
The number of physiognomic divisions into which 
vegetation may be divided is, of course, a matter of 
