The Plant 
41 
have hairs on them. These act as a protection in one way 
or another. Most of us are well acquainted with the sting- 
ing hairs of the nettle. In some plants these hairs catch 
the dust, and prevent it from getting into the stomata. 
Again, some leaves, such as those of the Holly, Laurel, &c., 
are protected by a very 
thick skin. Trees which 
usually grow on very ex- 
posed places have needle- 
like leaves, to prevent them 
from being destroyed by 
the wind, e.g. Pines and 
FirS. Other plants, which Vertical Section of Portion of Leaf of Holly 
flourish on rocky or very 
poor ground, where they are liable to be dried up, have 
specially adapted leaves that are curved at the margins, 
and so retain the moisture, e.g. Heather, Mosses, &c. 
Again, we have the water plants, with two kinds of leaves, 
as the Water Ranunculus. Thus, as we advance step by 
step, we see how 
Nature has adapted 
everything to the 
greatest advantage. 
There are the leaves 
which float on the 
surface of the water, or grow above it; then there are the 
leaves which grow under the water. The latter are finely 
divided, like thick threads. The advantage of this will 
readily be seen. As this plant often grows in streams, the 
current would tear the broad, flat leaves, and so prevent 
the work of food manufacture going on satisfactorily; but 
Folding of Moss Leaf 
