CHAPTER TWENTY-SEVEN 



FRUITS AND SEEDS 



The term " fruit " is commonly used to designate a great 

 variety of organs that are developed as a result of the flowering 



Fig. i6o. Types of fruits: A, enlarged receptacle with imbedded nut-like pistils (water 

 lotus) ; B, fleshy stem tip with a central cavity containing many minute flowers (fig) ; 

 C, enlarged fleshy receptacle with pistils attached to surface (strawberry) ; D, fleshy urn- 

 shaped calyx-tube with pistils inserted on the inner surface (rose). 



of plants. The direct result of pollination and fertilization is the 

 production of the seed. The indirect effect of pollination is the 

 further development of adjacent structures. The pistil, or at 

 least the ovulary wall, enlarges and sometimes becomes greatly 

 thickened. Primarily the fruit is the enlarged pistil or ovulary, 

 but in many cases the calyx and the receptacle also enlarge and 

 form a part of the fruit, sometimes most of it. The pineapple is 

 a fruit in which an entire flower cluster has become fleshy, and 

 this fruit is formed without fertilization. Like the common 

 banana, it is seedless. 



In some fruits the enlarged pistil forms a thin wall inclosing 

 the seeds. At maturity the pistil wall dries out, forming a dry 

 fruit. In others the pistil wall, or some of the adjacent structures, 

 become enormously enlarged by the formation of soft parenchyma 

 tissue in which sugars, fats, acids, and other substances accumu- 

 late. These are distinguished as fleshy fruits. Among the dry 

 fruits the most familiar are the grains, illustrated by wheat, 

 barley, and corn. The outer coat is the ovulary wall ; the embryo 

 is small, and most of the seed is made up of the starchy endosperm. 



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