PARASITIC PLANTS 213 
or greedy, people who fastened themselves on to a rich 
man in order to share his dinner, putting up for its sake 
with the insults and degradation that were generally 
experienced. The parasitic plant, however, gets the 
dinner, and, so far as we know, its unwilling host has 
not even the compensation of giving its candid opinion 
of its guest. At any rate, it cannot express it Im ways 
that we can understand, and we only see the entertainer 
withering away.) 
But there is a danger that we may be too sweeping 
in our condemnation and include in the list plants that 
are really getting their own living entirely. One some- 
times, for instance, hears the Ivy spoken of as a parasite, 
but this is really quite undeserved. The Ivy may use 
a tree as a prop, but it never thinks of sinking wells 
into it, and robbing it, and is just as well off when 
it can find a friendly wall. On the other hand, it must 
be confessed that the tree is not by any means always so 
well off, for if the ivy is very fine and luxuriant, the 
supporting tree may easily be robbed of its fair share 
of light and air, and so practically be suffocated. In the 
same way, many tropical creepers bind so tightly around 
the trees up which they climb, that the trunk, as it 
endeavours to grow, is deeply furrowed by the twining 
bands of the creeper, which refuse to give way at all. 
On a small scale, you may sometimes see that an ivy 
stem has half-throttled a tree, and the honeysuckle not 
infrequently leaves marked traces. Still, this is not | 
exactly parasitic, though very unpleasant for one party 
to the transaction. The distinction may be illustrated 
thus. If there is a stream running through two farms, 
one farmer diverts it all on to his own land and leaves 
his neighbour the dry bed. That is more or less the 
