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So you can understand that plants which grow in 
dry, sunny places, where there is little drinking water 
for the roots, and where the sun beats constantly on 
fie. leaves, must take every care that there is no 
waste of water. 
And if you keep your eyes open, you will discover 
that many of the plants which grow in such places 
screen themselves from the full heat of the sun bya 
coat ot hairs. 
The plant called “life everlasting” is one which 
grows in dry, open, sunny places. It clothes its leaves 
“with silky hairs, and so prevents them from throw- 
ing off too quickly the small amount of water its roots 
are able to provide. Without this silky coat, the sun 
would suck its leaves quite dry of water. 
Sometimes a leaf has only a few of the little leaf 
mouths through which most of the water passes. As 
these mouths are wide open only in the sunlight, and 
as often the rest of the leaf is covered with a thick 
skin which prevents the water from slipping away (as 
a little of it nearly always does) through the cell walls, 
such a leaf will hold its water supply and keep fresh 
for along time. Such leaves as these we find on what 
we call “evergreen” plants. The pines and hemlocks 
which light up the woods all winter have these thick- 
skinned, few-mouthed leaves, which throw off so little 
water that even when the ground is frozen hard, and 
gives no drinking water to the roots, they are able to 
keep fresh by the careful way in which each one 
hoards its own little supply. 
