238 



A YEAR IN SCIENCE 



getting it for itself, pollen is caught on the hairs of the 

 body and legs of the bee and is thus carried from flower 

 to flower. Bees, butterflies, moths, and some other 

 insects feed on the nectar of plants. These insects 

 have mouth parts Avhich are very much elongated, 

 forming a tube-like structure. This enables them to 

 reach the nectar which is usually at the base of the 

 flower. In so doing, however, the body of the insect 

 must brush against the stamens and pistils. In this 

 manner pollen is then transferred from one flower to 

 another. 



Wind pollinated flowers aTe usually very inconspicu- 

 ous. They are structures which you probably have 

 never considered flowers at all. The flowers of most 

 trees, grasses, and grains are wind pollinated. 



Seed dispersal. The 

 function of the seed 

 is to produce a new 

 plant. In order to do 

 this, however, certain 

 conditions of light, 

 air, moisture, and 

 food are necessary. 

 Only a small propor- 

 tion of the seeds an- 

 nually produced can 

 grow. This is be- 

 cause a seed must not only -have favorable conditions of 

 light, moisture, etc., for growth, but it must find a place 



Fig. 102. Milk weed fruit, showing 

 method of seed dispersal. 



