CHAPTER IX 

 SEEDS AND SEEDLINGS 



Seeds. — Seeds are the result of fertilization and are the final 

 product in reproduction. The seed is the most important and 

 last product of the parent plant. It contains the embryo which 

 develops into the seedling or first stage of the next generation. 

 Germination may be considered as the birth of the young plant. 

 Seeds present many superficial differences in size, shape, color 

 and other characters, but may usually be grouped into three 

 different types. The bean, castor bean and com are good ex- 

 amples of these three different types and have been selected for 

 study. However, it should be remembered that the corn is not 

 a seed but a true indehiscent fruit. We have already learned 

 (page 98) that the seed, regardless of size, shape, color or the 

 species of plant from which it is derived, consists of three parts : 

 (a) an embryo or young plant, (h) a supply of food which is 

 stored either within the cotyledons of the embryo or as an endo- 

 sperm or nucellar perispeirm. immediately surrounding the 

 embryo or both and (c) an outside covering consisting of two 

 or sometimes only one seed coat. The value of the seeds as 

 food for man and animals depends primarily on the amount 

 and character of the stored food and the absence of distasteful 

 and poisonous substances. 



Bean Tj^e. — Thisis a dicotyledonous seed in which the food 

 is stored in the cotyledons. An examination of the outside of the 

 bean shows the hilum or scar which marks the point of attach- 

 ment to the pod. Near one end of the scar is a small mark, which 



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