PLANT ASSOCIATIONS 33 
though not in flower, Herb Robert, Meadowsweet, and a cae 
number of Grasses, all in the perfection of blossom. 
It should be noticed how many climbing plants are found 
in hedges—Honeysuckle, Bindweed, Black Bryony, White 
Bryony, Clematis, Roses, Blackberry, ete. The mechanism 
by which plants climb has already been discussed (Chapter I.). 
In some parts of the country, instead of hedges stone walls 
are built, and in the crevices between the stones a large 
number of plants will be found. In South Cornwall the 
number of plants found on stone walls is striking. Ferns 

abound, and the following not very common Flowering Plants 
may be mentioned: Valerianella, Subterranean Clover, Field 
Madder, Pennywort in abundance, Trigonella. These plants 
must be more or less xerophytic in character, as there is no 
great depth of soil for them. They are for the most part 
small, creeping, and very hairy. 
In the next chapter some suggestions as to the practical 
work that should be done in order to map out the vegetation 
of a district on these lines is given. 
BIBLIOGRAPHY. 
Geographical Journal, April, 1902: “Geographical Distribution of 
Vegetation in Yorkshire,” by Dr. Wil'iam G. Smith and C. E. Moss, R.E. 
‘‘ Open-Air Studies in Botany”: Lloyd Preger. 
