194 



PLANTS AND MAN 



The Pome Fruits 



In the formation of a pome fruit the ovary of the pistil forms 

 a core within which are the seeds; the receptacle and calyx of the 

 flower enlarge and envelop the core with fleshy tissue which 

 forms the edible portion of the fruit. Thus such pome fruits as 

 the apple, pear and quince are accessory fruits with the bulk of 

 the fleshy portion being produced by other parts of the flower 

 than the ovary (fig. 131). 



Fig. 131. — Pome fruits such as the apple are accessory fruits with the | 

 bulk of the fleshy portion produced by the receptacle and other parts of the | 

 flower. I 



The APPLE genus includes some twenty species of trees native 

 to North America, Europe and Asia. Our indigenous species are 

 all known as crab apples, and bear small bitter fruits. Few of 

 these are cultivated, most of the orchard varieties being derived 

 from plants native to eastern Europe and Western Asia. Apples 

 have been cultivated for at least three thousand years; twenty 

 two varieties were known to the Romans, and since that time 

 there have been developed an estimated six thousand horti- 

 cultural varieties. English colonists introduced the European 

 apple into this country after they found that the native species 

 were useless. 



Apples average 80 to 85% water, with varying amounts of 

 sugars in solution. During the ripening process original starches 

 of the fruit change to sugar and the amount of malic acid (which 



'^. 1. 



