Cii. XVT.J 



GERMINATIOIM. 



99 



Pig. 67. 



411. The radicle, ot 

 descending root, is usu- 

 ally first to break through 

 the coats of the seeds ; 

 it commences its journey 

 downward, to seek in th 

 earth nourishment for the 

 future plant, and to fix it 

 firmly in the earth. This 

 constitutes the root, and 

 always takes a down- 

 ward course, in whatever 

 situation the seed may 

 have been placed in the 

 ground. 



412. A botanist plant- 

 ed in a pot, six acorns, 

 with the points of their 

 embryos upwards. At the 

 end of two months upon 

 removing the earth, he 

 found that all the radi- 

 cles had made an angle 

 in order to reach down- 



vvards. It is supposed that if the root met with no obstruction 

 in going downwards, it would always be perfectly straight. 



Fig. G8. 413. Fig. 68 is the representation 



of a germinating seed of the Foui 

 o'clock ; it will be seen that the radicle, 

 #, has made nearly a right angle in 

 turning downwards ; the plume is not 

 developed. 



414. If you put into a tumbler of wa- 

 ter some cotton, and place upon it some 

 seeds of rice or wheat, you will see all 

 the fibres shooting from the seeds, in a 

 perpendicular direction, downwards. It is a very simple and 

 interesting experiment. Some ascribe this phenomenon to the 

 laws of gravitation, by which the root is attracted towards the 

 centre of the earth; others say that the radicle, stimulated by 

 moisture, naturally extends itself in the direction from which 



411. What direction does the radicle take? 



412. What experiment did a botanist make with acorns? 



413. What does Fig. 68 represent ? 



414. Whar experiment is mentioned, and what are some of the 

 assigned for 'b? downward rnnixe of rhp radirle? 



