436 



BOTANICAL GAZETTE 



[DECEMBER 



conclusion, however, does not hold for the vine as a whole. This is 

 illustrated by the straight slope lines with curves A and C, fig. 6, 

 which were obtained from widely separated parts of the same vine. 

 Compare also the final twists per centimeter for nos. 2 and 4 in 

 table II. 



Lignification studies 



The fact that increase in diameter does not account for the final 

 development of rigidity has already been mentioned. It occurred 



TABLE III 

 Lignification tests: flowering bean 



*The terminal part; the number of this internode was not counted and so is called n. 



to the writer that studies in lignification might be useful. For this 

 purpose rigidity and its coefficient were determined on adjacent 

 parts of stems of the flowering bean and of the black bindweed, and 

 free-hand sections from the middle of each specimen were treated 

 with 5 per cent phloroglucin followed by strong HCl.'* In this 

 way the lignin was stained reddish violet. In tables III and IV 

 the data are given for two such experiments. When the observa- 



* Chamberlain, C. J., Methods in plant histology. 

 1905. p. 62. 



University of Chicago Press. 



