THE FLOWER AND ITS PARTS 105 
of wind. The flower swings a little, and the raindrop 
quietly rolls off. 
Sometimes the stamens themselves assist in the process. 
When damp is felt, the valves which allow the pollen to 
escape close up, and at least secure what is left. Many 
flowers are guarded by the leaves, which form, as it were, 
a slate roof above them, and let the rain slide to the 
ground. All of these methods, and others which it would 
be too long to recount, you may notice for yourselves in 
any garden, or in a meadow where flowers are plentiful.* 
Provision against danger on the way, however, does: 
not solve the problem of getting the pollen-grain to the 
ripe stigma, and we have still to see how this is done. 
Now a stigma may be fertilised either by the pollen from 
its own stamens, or by pollen from some other plant of 
the same kind, ze. by “Self-fertilisation” or by “ Cross- 
fertilisation.” The first is the simplest, and the most 
certain, but it seems to be proved that the latter is more 
advantageous to most plants. To secure it, many ensure 
that there shall be no self-fertilisation by having only 
stamens on one individual, and only pistils on another. 
Others so arrange it that the two parts ripen at different 
times, and when the pollen is just ripe, the stigma 1s 
either not yet ready for capturing pollen, or it was ready 
some time before, and has been fertilised by an outsider. 
Plenty of plants, however, are content with the simple 
method, which is easily secured, and the pollen of the 
flower is deposited on the stigma by actual contact of 
stamens and pistil. When this method is adopted, the 
flowers are usually small and inconspicuous, for they have 
* Another reason for plants objecting to water in their flowers is that 
it would wash away their honey, and they could then offer no induce- 
ments to insects to visit them. 
