The Improvement of Crop Plants 95 



no danger that the flower will receive other pollen. 

 (Exp. 3.) 



Plants entirely different from one another, as the Plants that 

 peach and the apple, cannot be made to cross. The crosse d 

 pollen of one has no more effect on the stigma of the 

 other than so much dust would have. 



Peculiarities in the reproduction of some plants. Special 

 Corn bears two flowers on the same stalk, the tassel, ? n atuml 

 furnishing the pollen, and the ear, bearing the ovules pollination: 

 (Fig. 73 and Exp. 5). Each grain of corn has a silk (a) of corn 

 attached to it, the end of which projects from the husk 

 (Fig. 74). Extending down the side of each silk is the 

 stigma upon which a grain of pollen must fall and send 

 its pollen tube all the way back to the ovule. If a grain 

 is shrunken on the cob, it is because no pollen grain 

 reached it. The side of a cornfield that faces the wind 

 is sometimes poorly pollinated and therefore will not 

 bear well. A single stalk or a single row of corn will not 

 do well for the same reason. 



In some plants pollen would be injured by dew, and (6) of other 

 the petals close at night for its protection. In many po 

 plants the pollen must be carried to its destination by in- 

 sects. Two kinds of some plants must be near together, 

 because one furnishes the pollen for the other. This 

 is the case with some strawberries (Figs. 75 and 76). 

 Squashes and melons bear fruit and pollen on separate 

 flowers, but both kinds of flowers are on the same vine 

 (Figs. 77 and 78). 



New varieties of potatoes may be secured by planting Seedling 

 potato seed (not " eyes." See page 135). But al- varieiies: 

 though potatoes often blossom, they seldom make any 



