22 



Elementary Work in Botany. 



16. Sprouting wheat 

 on the left; wild oats on the 

 right, a, b. Plumule, c. The 

 twisted beard which helps to 

 plant the seed. 



to keep the truth a secret. Try to decide this question by 

 a careful study of your seedlings. 

 They must tell you, also, what they 

 do with endosperm when they have 

 any; and how they get along without 

 it when they have none. 



Make drawings of the present ap- 

 pearance of several of your seedlings. 

 In which have the cotyledons grown 

 most? In which have they not grown 

 at all ? What have the cotyledons of 

 the latter done ? 



Compare your sprouting wheat 

 with the figure on this page. Did the 



three roots from the caulicle begin to grow at the same time ? 



EXERCISE 15. 



Compare your seedlings; scanet runner, common bean, 

 and sunflower. The cotyledons of the first do not appear 

 above ground, but those of the other two are pushed up by 

 the hypocotyls after they have securely anchored their bases 

 by putting out rootlets. The cotyledons of the sunflower 

 become broad, green leaves; those of the bean evidently 

 never do any real leaf-work, and, apparently, might as well 

 have remained where the seed was planted. 



When do the cotyledons of the bean fall off? Why does 

 not the plumule of the sunflower begin to grow as soon as 

 that of the bean ? How are the first two leaves of a bean 



