28 TYPES OF BRITISH PLANTS 
Just the same kind of harm is done by the caterpillars, 
which clear whole branches, as you may see on lime-trees 
where the long green buff-tip caterpillar has been at 
work. This is not quite so fatal, for in the first place 
the whole tree is not usually attacked, and in the second 
the devastation is not generally serious until the summer, 
when the leaves have already been able to do a great 
part of their year’s work, though you may often see a 
gooseberry bush dropping its fruits, the leaves being too 
few to feed them. 
Various interesting devices have been adopted by 
plants to preserve their leaves. In many the leaf-buds 
are shrouded when young by thick, scaly, overcoat leaves, — 
such as one may see in the horse-chestnut. Some, such 
as the elm, appear to have a bitter taste, and hardly any 
caterpillar will come near them. Many shrubs, in order 
to protect themselves against browsing cattle, are armed 
with stiff thorns, such as are found on both hawthorn 
and bramble. Others, such as the furze or gorse, have all 
their leaves modified into spiny and prickly shapes; the 
nettle arms all its leaves with stings, and the thistle 
fringes them with penetrating spines, which secure them 
incidentally from being sat upon for long by lazy human 
beings. 
On the other hand, it is most interesting to note how 
the animals against whom they are preparing get them- 
selves ready for the fray. We know how the donkey’s 
mouth and throat have been hardened until he looks on 
thistles as a mere delicacy to tickle his appetite, and 
the giraffe has developed such leathery lips that he 
browses comfortably upon acacia-thorn, whose spines 
tear a man’s clothing to rags if he tries to force his 
way through it. 
