ECONOMIC OR USEFUL PLANTS 



409 



peach but the exocarp is thin, and when ripe, cracks open, freeing 

 the nuts. In its native country it is often found on the markets 

 green. It is eaten in this condition by cutting open the flesh to 

 secure the green nut. The cultivated cherries are derived from 

 two species native to Europe, one of these producing the varieties 

 of sour cherries which are extensively grown in the eastern 

 United States. In western New York they are largely grown 

 for canning. The sweet cherries form a large and tall tree, are 

 also grown in the eastern United States, but most extensively in 

 California. The native species in this country have small fruits 

 and have not yet shown adaptability to improvement in cultiva- 

 tion. One, the wild black cherry (Prunus serotina), is very 

 valuable for lumber. 



577. The pea family (Papilionaceae) . This is a large and 

 important family. The name refers to the supposed resemblance 



Fig. 393- 



Peanuts in the field, showing how the earth is drawn up to cover the young forming pods; 

 in front a few plants pulled, showing the peanuts. From Bureau Plant Industry. 



of pea flowers to a butterfly (Papilio). The flower and fruit are 

 described in paragraphs 249-251 and 320. The name of the family 

 is sometimes given as Leguminosa, the name being taken from the 

 characteristic fruit which is a legume or pod. Many of the mem- 

 bers of the family have showy flowers and are grown for orna- 



