Corn Investigations 
35 
Fig. 5. — An ear of corn at silking time. Every kernel has its own silk 
and must be fertilized separately. In the process of fertilization, 
pollen falling on the silk germinates and grows a pollen tube thru 
the silk to the kernel, to which it conducts the two sperm nuclei. 
One of these nuclei fuses with the egg nucleus to form the initial 
embryo nucleus, and the other with the two polar nuclei, forming the 
initial endosperm nucleus. This entire process has been found to be 
completed within approximately 24 hours’ time. Fertilization is 
reflected in the discoloration and drying of the silks in from 42 to 
72 hours after pollination. 
