CHAPTER VIII 

 SEED GERMINATION 



44. What a Seed is. — A seed is a very small, or embryo 

 plant, the germ, having food stored in or around.it, by 

 which it is nourished until it is able to maintain an inde- 

 pendent growth. Both the germ and the stored food are 

 covered and protected by a seedcoat, into which they are 

 very tightly packed. 



45. Two Great Classes of Plants. — The little plant 

 within the seed, called the embryo, or germ, consists of 

 three parts; viz., the leaf or leaves, which are called the 

 seed leaves, or cotyledons ; the hypocotyl, or the part of the 

 tiny plant below the cotyledons, the lower end of which 

 is called the radicle; and the plumule, or the part above 

 the cotyledons. 



Those plants which bear inclosed seeds, — and this 

 includes practically all common plants except evergreen 

 trees — are divided into two great classes. This classifi- 

 cation is based upon the number of seed leaves, or cotyle- 

 dons, in the embryo. If only one cotyledon is present, 

 the plant is known as a monocotyledon ; if two are present, 

 it is a dicotyledon. These two great classes of plants 

 differ not only in their embryos, but still more widely in 

 their stems and leaves, so that we are easily able to dis- 

 tinguish them at any stage of their existence. These 

 differences will be shown in later chapters. 



The monocotyledons include the plants of the grass 



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