THE FLOWER 215 
such as small birds, may be effective. In submerged plants the 
transfer may be made by water. 
Wind-pollination. Some flowers have no perianth at all, and 
others very. inconspicuous ones. In such cases the pollen is fre- 
quently produced in large quantities and is carried by the wind 
from one flower to another. Indian corn is a good example of a 
plant that has inconspicuous } 
flowers and is wind-pollinated. 
The male flowers occur at the 
top of the plant in what is 
commonly known as the tassel. 
The female flowers are pro- 
duced lower down in _ heads, 
which after fertilization become 
the ears of corn. ‘The long, 
silky hairs which project from 
these ears are the styles and 
stigmas. The female flowers 
are thus in a favorable posi- 
tion to have pollen blown to 
them from the male flowers of 
other plants. 
Grasses, many trees, and 
some shrubs and herbs are wind- 
pollinated. In order to insure 
pollination, wind-pollinated spe- 
cies produce large quantities of pollen; and when the pistils 
and stamens occur in separate flowers, the male flowers are very 
much more numerous than the female ones. The production of 
iarge quantities of pollen is evidently necessary when most of 
it must be wasted, as is the case with wind-pollinated species, 
where it is only by rare chance that a grain of pollen will be 
blown to the stigma of the same species. The stigmas of wind- 
pollinated plants are usually broad and feathery, and so afford 
a large surface for catching pollen (Fig. 216). This naturally 
increases the chance of pollen’s reaching the stigma. Many 


Fig. 216. Feathery stigmas of a 
grass. (x12) 
