THE PARTS OF LEAVES 29 



must act the part of foliage (i, e., perform the 

 functions of green leaves). If, for any reason, 

 the leaf -blades were to perish, it is conceivable that 

 the stipules could maintain the plant. This actually 



PIG. 23. 

 Virginia creeper. 



occurs in some plants (as in some of the vetches) , in 

 which the entire foliage is made up of large stipules. 



33a. A leaf which has no petiole is said to be sessile (i. e., "sit- 

 ting"), a term applied to any member which is destitute of a stalk 

 or stem, as flowers, stamens, or fruits. 



34. How shall we define the parts in the leaf of 



