28 THE NATURE-STUDY OF PLANTS 
The Nettle’s sting, however, must be examined 
with a lens if we want to get a good view of the swollen 
base that contains the acrid poison, and there are 
many other plants the defensive weapons of which 
are not so easy to observe. 
The leaves of many Grasses and Sedges, for example, 
have edges which are distinctly rough to the touch, 
but they are really very 
CSS ==, much worse than that, for 
PR they are fine and sufficiently 
sharp saws. A little mag- 
nification will show the 
teeth. This feature of the 
Fria. 10.—(a) Margin of leaf, Sedges, which characterizes 
Rye Grass, x 35. (6) Mar- the stem as well as the 
gin of leaf, Wood Sedge. . 
% 35. leaves of some of them, is 
: sufficiently pronounced to 
have given them a scientific name, Carex, which is 
derived from a Greek word meaning “ to cut.” I have 
not infrequently had my own fingers cut quite deeply 
enough when collecting specimens, and in addition 
to keeping slugs, snails, and caterpillars at bay such 
saws as these are capable of inflicting nasty wounds 
on the soft and tender lips and tongues of browsing 
animals. 
Most Grasses are particularly hard and difficult 
to chew, the reason being that they are clad in a 
flinty mail in the shape of a coating of silica, the 
substance which forms the bulk of an ordinary flint ; 
while straw is hard, shining, and decidedly uninviting 
as food, for there is a good deal of silica in it as well. 
The teeth, too, which form the fine fret-saws on 
the edges of the leaf, are minute but hard, sharp 
flints, to which fact they owe their efficiency. 


















