POLLINATION 15 



Self -pollinated plants. In the flowers of wheat, oats, 

 and peas, the pistil is usually pollinated by the pollen that 

 is produced in the same flower. Such plants are said to 

 be self-pollinated. Self-pollinated plants do not mix with 

 other kinds in the field. 



Cross-pollinated plants. On the other hand, the pistils 

 of some kinds of plants generally receive pollen that grows 

 on a different plant. Such plants are said to be cross- 

 pollinated. If a farmer grows a white and a yellow 

 variety of corn side by side, these will be mixed in a few 

 years. This is because the light pollen dust from one 

 kind is carried by the wind to the silks of the other kind. 

 Many a boy has had his patch of popcorn ruined by 

 planting it near field corn that bloomed at the same time 

 as the popcorn. You have perhaps noticed the pollen of 

 corn as it was carried by the wind, like fine dust. You 

 have probably also noticed in the spring clouds of yellow- 

 ish dust blown from the pine trees. This dust is light 

 pollen carried by the wind. 



How insects help the flowers to form seed. Some plants 

 have heavy pollen, which the wind cannot so easily carry. 

 Cotton is one of these. Such plants generally have gayly 

 colored petals that attract the insects. Even children 

 like to taste nectar by touching the tongue to a blossom of 

 honeysuckle after its petals are removed. The flower of- 

 fers nectar to insects and in return the insects usually 

 bring pollen from a blossom of the same kind and place 

 this on the pistil. If we notice a bee as it enters a flower, 

 we observe that much yellow dust adheres to its body. 

 This is pollen that it rubs against while visiting other 



