The Nature and Origin of Stipules. 49 



tionary changes, by increased development, by basal or total 

 degeneration, by secondary adnations and various textural modi- 

 fications. They receive their vascular bundles t^^pically as 

 branches of the lateral ones of the leaf-trace. 



5. The lateral portions of the primitive leaf therefore represent 

 in potential the ligule, the ochrea, the margins of sheathing peti- 

 oles and stipules, but they are often incorporated with the other 

 portions as the wings of petioles and as lateral basal portions 

 of leaf-blades. 



