122 THE BEAUTIES OF NATURE CHAP. 
It is, I think, well established that the 
main object of the colour, scent, and honey of 
flowers is to attract insects, which are of use 
to the plant in carrying the pollen from flower 
to flower. . 
In many species the pollen is, and no doubt 
it originally was in all, carried by the air. 
In these cases the chance against any given 
grain of pollen reaching the pistil of another 
flower of the same species is of course very 
great, and the quantity of pollen required is 
therefore immense. 
In species where the pollen is wind-borne 
as in most of our trees — firs, oaks, beech, 
ash, elm, etc., and many herbaceous plants, 
the flowers are as a rule small and inconspic- 
uous, greenish, and without either scent or 
honey. Moreover, they generally flower early, 
so that the pollen may not be intercepted by 
the leaves, but may have a better chance of 
reaching another flower. And they produce 
an immense quantity of pollen, as otherwise 
there would be little chance that any would 
reach the female. flower. Every one must 
have noticed the clouds of pollen produced by 
