130 THE STORY OF THE PLANTS. 



wind from some other plant that grows close by 

 them. As soon as they have begun to set their 

 seeds the stigmas wither, and then the male flow- 

 ers open in a bright yellow mass, the stalks of 

 their stamens lengthening out as they do so, and 

 allowing the wind to carry the pollen freely. 

 Here, although the males are above, the peculiar 

 arrangement by which the females ripen first 

 makes it practically impossible for the flowers to 

 be fertilised by pollen from their immediate neigh- 

 bours. 



The devices for wind-fertilisation, however, 

 are on the whole less interesting than those for 

 insect-fertilisation, so I shall devote little more 

 space to describing them. I will only add that 

 two great classes of plants are habitually wind- 

 fertilised : one includes the majority of forest 

 trees; the other includes the grasses, sedges, and 

 many other common meadow plants. 



The wind-fertilised forest trees belong for the 

 most part to the fivefold group, and have their 

 flowers, as a rule, clustered together into bang- 

 ing and pendulous bunches, which we call catkins. 

 It is obvious why trees should have adopted this 

 mode of fertilisation, because they grow high, and 

 it is easy for the wind to move freely through them. 

 For this reason, most catkin-bearing trees flower 

 in early spring, when winds are high, and when 

 the trees are leafless; because then the foliage 

 doesn't interfere with the proper carriage of the 

 pollen. In summer the leaves would get in the 

 way ; the pollen would fall on them ; and the 

 stigmas would be hidden. Most catkins are long, 

 and easily moved by the wind ; they have numer- 

 ous flowers in each, and they shake out enormous 

 quantities of pollen. This you can see for your- 



