Flowers 
The spider orchis succeeded in getting only 6 to 8 per 
cent. of its flowers fertilised, 
Quite as wonderful are the ways in which flowers 
arrange their reactions to light and sunshine so that 
the movements of the stalk at every stage are exactly 
what suits its purposes best. 
The common Geranium pratense is a very interesting 
example. At first the flower-stalk grows upwards, then, 
as soon as the flower develops, its own weight causes it 
to droop or hang downwards, 
Soon the flower becomes again erect, which is brought 
about by a response in the opposite direction to the 
action of gravity, or, as it is called, negative geotropy. 
Then the flower turns a little so that its petals are nearly 
in a vertical plane (weight and negative geotropy). 
After flowering the young fruit hangs downwards, 
but as soon as it is ripe, gravity again stimulates it and 
the mature fruit is upright and, by the growth of the 
stalk during its ripening, keeps well above the grasses and 
herbage, so that it is in the most suitable position for 
distributing its small carpels,” 
So by this extraordinary series of fitting reactions, it 
does what is best for itself at every stage of development. 
Even from this short sketch it will be seen that a 
modern flower is a very complex product. Its own 
sensitive protoplasm and the delicate balance of supply 
and demand between root, stem, leaves, and blossoms 
are sufficient to explain why changes in sunshine, in 
rainfall, and in soil should produce slight tentative 
variations. 
But these variations are not allowed to develop 
riotously and unchecked. Each attempt has not only 
to prove itself fit to withstand weather and insect- 
enemies, but it must be a more alluring enticement to 
artistic and intelligent insects. 
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