52 PISTILS AND STAMENS 



velopment of these kernels, the sperm portion of the endo- 

 sperm nucleus dominated, and thus the endosperm is like the 

 endosperm of the pollen parent. The sperm may even deter- 

 mine the color and fat content of the endosperm. On the other 

 hand, if Field Corn is pollinated with pollen from Sweet Corn, 

 then usually the primary endosperm nucleus dominates and one 

 sees no effect of the sperm. Thus it is seen that the character 

 of the endosperm of a seed may be determined by either of the 

 members which fused in forming the endosperm nucleus. 



The kernels in Figure 57 which have the endosperm features 

 of Field Corn also have embryos with opposing tendencies. 



Fig. 58. — Pears showing a difference between the results of self- and cross- 

 pollination, a, fruit resulting from self-pollination; 6, fruit resulting from 

 cross-pollination. After Waite. 



These embryos received from the egg tendencies to develop into 

 plants having all of the features of Sweet Corn. They also re- 

 ceived from the sperm tendencies to develop plants having all 

 of the features of Field Corn. In the hybrid offspring it is likely 

 that some of the characters of both parents will be present. 



The Kind of Pollination Giving the Best Results. — Plants in 

 general seem to favor cross-pollination and often have their 

 flowers so constructed as to prevent self-pollination. In some 

 plants, however, as in the small grains, Beans, Peas, and some 

 other plants, self-pollination is the usual method and gives good 

 results. Red clover, many fruit trees, and many other plants 

 require cross-pollination and will develop very little seed or fruit 



