1904.] Notes on the Statolith Theory of Geotropism. 489 



The trough was again reversed after a tracing of 5 had been made, 

 the right side being now higher, and the angle about 30°. Here again 

 the roots on the right bend down and on the left up, as will be seen by 

 comparing sections 5 and 6. 



The roots, therefore, show clearly a power of curving up or down so 



Fig. 5. 



as to assume" their proper angle with the horizontal just as normal 

 secondary roots do in similar circumstances. The only obvious excep- 

 tions to the^rule are in roots R iv, v, vi, where a downward bend occurs 

 between sections 3 and 5 or 4 and 5, as the case may be ; here the 

 curve should either have been absent or in the upward direction. 



After section 6 was traced the trough was exposed to light and 

 sections 7 and 8 were traced. It will be seen by comparing 6 and 8, 



