THE FORMATION OF SEEDS 



edible fruits is one modification of the Pericarp, and 

 is formed usually from the placenta, and serves prox- 

 imately for the dissemination of the seeds, being eaten 

 by animals, through whose digestive organs the seeds 

 pass unchanged. Jn other fruits the pericarp is hard, 

 ligneous and not digestible, and serves only as an 

 additional protection to the enclosed seed or seeds 

 until the conditions are favorable for germination. 

 Their dissemination is provided for in many ways with 

 which we are all familiar. In all seeds the active, 

 living germ constitutes but a very small portion 

 thereof. The embryo, or germ, is only a nodule, at 

 or near one end of the seed. It is protected by its 

 tough outer covering from the wet, and is capable 

 of withstanding with impunity an excessive degree of 

 cold. If kept dry, seeds retain the potency of life 

 for many years. 



The principal part of the seed consists of an amy- 

 laceous mass of granules of starch, albumen and oily 

 substances, which serve as food to the young plant, 

 and are consumed by it when it germinates and 

 begins to grow. The processes of floration and of 

 fructification are very exhausting to the parent plant. 

 The formation of a flower and the growth of the seed 

 require a large expenditure of material and of vital 

 energy that are furnished by the oxidation or degra- 

 dation of the parent tissues and of the stored-up oil, 

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