POLLINATION AND FERTILIZATION 
143 
maturing, close over the stigmas and insure self-pollination. 
The fact that seeds are abundantly produced shows that 
Fic. 126. Part of a 
corn tassel (stami- 
nate flower cluster) 
br,a bract: st, stamens. 
One half natural size 
the pollination is 
effective. 
136. Corn; pol- 
lination by wind. 
Indian corn af- 
fords an admirable 
example of polli- 
nation effected by 
aid of the wind. 
The pollen is pro- 
duced in the staminate flower 
clusters, which are commonly 
known as the twsse7 (fig. 126), 
borne at the summit of the 
cornstalk. Each cluster con- 
sists of many stamens, and every stamen 
produces a multitude of dry, dust-like pol- 
len grains, which are carried for long dis- 
tances by the wind. The familiar corn silk, 
which protrudes from inside the husk of 
the young ear of corn, is composed of 
many thread-like styles (one from each 
grain of corn). The styles terminate in a 
two-forked, hairy stigma (fig. 127 C, sf). 
The brush-like character of the protruding 
stigmas makes them very efficient in catch- 
ing flying pollen grains. 
If the pollen from a corn plant is shaken 
down upon the stigmas of the same plant. 
self-pollination only is effected and poor seed results. If the 
pollen which pollinates an ear comes from another corn plant, 
cross-pollination is effected and good seed results. Figure 159 
shows the difference in growth between plants produced in 
the next generation from the two kinds of seed. 
