Ckapter 9 



THE CEREAL FRUITS 



The storage of food in reproductive organs has been a fortu- 

 nate habit of plants, from the human viewpoint; for what is food 

 for a developing plant embryo or for a hungry animal is also 

 food for man. Fruits, because of their high water content, 

 actually afford small amounts of energy-giving or protoplasm- 

 building material ; however, they furnish an abundance of vita- 

 mins and minerals and add a pleasing variety to human diet. 

 Seeds, on the other hand, have a low water content and store a 

 considerable amount of nutrient material in a small space. From 

 time immemorial seeds have played an important role in sus- 

 taining human life. 



In Chapter 3 the various post-fertilization changes in a flower 

 were discussed, with the ensuing formation of the fruit. The 

 typical fruit develops from the enlarged ovary of the pistil while 

 the ovules become seeds, buried in the tissue of the fruit. In some 

 cases the maturing ovary forms a thin dry coat which protects 

 the seeds, in other cases it becomes thick and fleshy. Thus there 

 are two common types of fruits: dry fruits, usually adapted for 

 dispersal by wind or mechanical means, and fleshy fruits dis- 

 persed by animals. There are numerous kinds of dry fruits 

 (fig. 101), but only two of these are of any significance as foods. 

 The ACHENE is considered the simplest type of dry fruit, being a 

 small one-seeded fruit which does not split open at maturity; 

 this is typically seen in the Buttercup Family. In a modified type 

 of achene known as a caryopsis the thin-walled fruit adheres 

 firmly to the seed coat, so that it is difficult to diff'erentiate 

 between fruit and seed. The caryopsis, represented by the grain 

 or kernel found in the cereals, has become one of the most 

 important of human foods. True nuts are also one-seeded modi- 

 fied achenes. Some dry fruits contain several seeds, others many; 



167 



