GABRIELLE L. C. HOWARD. 93 



width (average width 11.1 cm. and 29.2 cm. respectively). 

 On Plate XIX are shown some of the leaves of the F. genera- 

 tion of this cross, drawn to scale. 



All the evidence accumulated during these investigations 

 tends to show that differences in width can be inherited quite 

 independently of the length. The very great effect of fluctu- 

 ating and temporary changes in environment on the size of 

 the leaves makes a thorough study of the inheritance of the 

 Avidth or of the length difficult and necessitates a large number 

 of measurements. Time has not permitted me to measure 

 sufficient leaves per plant to make any very definite statements 

 as regards the factors composing these characters. As regards 



>pe 9 X Type 51. 



