THE CASTOR BEAN 



123 



FIG. 66. LONGITUDINAL SECTIONS 



OF THREE SEEDS 



Showing the enclosed young plant or embryo, e, 

 and food, /. In the middle figure, the food is deposited 



After a few days it stops growing and becomes surrounded 

 by a hard shell, and is now known as a seed; in this form, 

 protected by its shell, it may remain dormant for some 

 time. If any seed is carefully examined it will be found to 

 contain a little plant, or 

 seedling, with a stem and 

 one or more leaves; Fig. 

 66. The leaves inside of 

 the seed are known as cot- 

 yledons, and while they 

 are true leaves they are 

 different in shape and 

 structure from the leaves 

 which this same plant 

 is to produce later when 

 the seed has germinated; 

 see Fig. 43. 



There is also deposited in the leaves of the embryo; in the two other figures 



the food is around the embryo. 



in the seed, either around 



the seedling or within it, a quantity of food upon which the 

 young plant can feed during the first few days of its life, before 

 it can feed itself from the soil. 



This whole process of fertilization, growth into a little plant, 

 and the development of the shell around it to form a seed, 

 occurs within the pistil of the flower. The flower in the mean- 

 time withers and the ovary increases in size to accommodate 

 the growing seeds. Eventually, the fruit is broken open 

 (dehiscence) and the seeds drop out. When this occurs the 

 duty of the flower is over and all its parts decay, leaving the 

 plant without flowers until the next season. From this de- 

 scription, it will be seen that there are in the flower at least 

 four different kinds of reproductive bodies: the male spores, 

 or pollen; the female spores, or embryo sac; the eggs which 

 develop from the female spores and finally grow into seeds; 

 and the male nuclei inside the pollen tube which fuse with the 



