HOW PLANTS GROW 349 



the embryo is of sufficient size and the proper amount 

 of food is stored, the ovary is mature and the fruit is 

 ripe. A fruit is a ripened ovary. 



Fruits and seeds are scattered by the wind, water, 

 animals, and by the fruit pods bursting open and throwing 

 out the seeds. Fruits are grown for the purpose of start- 

 ing new plants away from the parent plants and also 

 to carry plants over unfavorable climatic changes like 

 cold weather during winter. Man makes conditions 

 favorable for plants to grow so that they will produce 

 large quantities of fruit for food. Make a list of plants 

 grown for their fruit; keep in mind that a fruit is a ripened 

 ovary. 



238. Production of New Varieties. In the previous 

 section we learned that some flowers are self-fertilized 

 and that most of them are cross-fertilized in order to 

 produce seeds which in turn produce new plants. When 

 the pollen from a flower of one plant falls on the stigma 

 of a similar plant, a seed is grown which when planted 

 will produce a plant that is more or less different from 

 either of the two parent plants. This difference may 

 not be noticeable or it may be very great. If seed is 

 always selected from plants which show a difference from 

 the parent plants, new varieties may gradually be pro- 

 duced. This selection may take place among wild plants 

 and thus produce new varieties, but man with his intelli- 

 gence is always selecting the best seed from the most 

 productive plants with the result that the farm crops 

 per acre. have greatly increased and many new and pro- 

 ductive varieties have been produced. Luther Burbank 

 of California has produced wonderful results simply by 

 selecting the plants that show an improvement and letting 

 them grow to produce seed for the next crop. Most 



