4 SEEDS AND SEEDLINGS 



sesses all the organs of a mature plant ; root, stem and leaf. All 

 the other parts of a plant with which we are familiar, such as 

 liowers and fruits, are moditications of these primary organs. 

 The food within the seed is especially well suited for nourishing 

 the young plant during the early stages of its development and 

 under favorable conditions of warmth and moisture is readily 

 utilized for this purpose. The highly nutritious character of 



Fig. 1. — a, diagrammatic under-side view of a grain of corn showing the embryo (em) and 

 the layers of food; b, longitudinal section of corn showing same parts; c, cross-section of 

 grain of corn showing the same parts. 



this stored food makes many seeds, such as corn, wheat, oats, 

 beans and peas especially useful as food for man and animals. 

 (Chapter IX.) The outside coverings of different kinds of 

 seeds are ecxtremely variable in character and have many modi- 

 fications, some of which aid in their distribution. These points 

 will be discussed later. (Chapter VII.) 



Two Classes of Seeds. — Seeds are extremely variable in 

 size, shape and color, but they can be readily grouped into two 

 main classes, monocotyledons and dicotyledons, dependent on 

 whether they possess one or two cotyledons or primary leaves. 

 These cotyledons are easilv recognized in most large seeds, such 



