CHAPTER XXVII 
HOW PLANTS PROTECT THEMSELVES FROM ANIMALS 
412. Destruction by Animals. — All animals are sup- 
ported directly or indirectly by plants. In some cases the 
animal secures its food without much damaging the plant 
on which it feeds. Browsing on the lower branches of a 
tree may do it little injury, and grazing animals, if not 
numerous, may not seriously harm the pasture on which 
they feed. Fruit-eating animals may even be of much 
service by dispersing seeds (Sect. 455). But seed-eating 
birds and quadrupeds, animals which, like the hog, dig up 
fleshy roots, rootstocks, tubers or bulbs, and eat them, 
or animals which, like the sheep, graze so closely as to 
expose the roots of grasses or even of forest trees to be 
parched by the sun, destroy immense numbers of plants. 
So too with wood-boring and leaf-eating insects, and snails, 
which consume great quantities of leaves. 
413. Some Modes of Protection from Animals. — Many 
of the characteristics of plants may be wholly or partly 
due to adaptations for protective purposes, while in par- 
ticular cases we cannot be sure of the fact. Perching on 
lofty rocks or on branches of trees, burying the perennial 
part (bulb, rootstock, etc.) underground, growing in dense 
masses, like a canebrake ora thicket of blackberry bushes ; 
all such habits of plants may be partly or altogether val- 
uable to the plant as means of avoiding the attacks of 
animals, but this cannot be proved. On the other hand, 
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