THE LEAF 



153 



198 199 200 201 202 



FIGS. 198-202. Margins of 

 leaves: 198, serrate; 199, den- 

 tate ; 200, crenate; 201, undulate ; 

 202, sinuate. (After GRAY.) 



Not only do leaves of different 



kinds exhibit these characteristics 



in varying degrees, but young and 



old leaves, or those on young and 



old plants of the same kind, often 



differ from each other in color, size, 



shape, texture, mode of attachment, 



and the like, to such a degree (Figs. 



203, 204) that one not familiar 



with them in both stages would 



hardly recognize them as belonging to the same species. 



The young leaves 

 of eucalyptus, mul- 

 berry, and some oaks 

 afford conspicuous 

 examples of such 

 differences, and they 

 exist between the 

 cotyledons and ma- 

 ture leaves of most 

 plants. 



Can you see any 

 benefit, in the case 

 of the plant whose 

 leaves you are study- 

 ing, that could be 

 derived from such of 

 the characteristics 

 named above as 

 they may exhibit? 



203 



204 



FIGS. 203,204. Leaves of paper mulberry tree: 

 203, leaf from an old tree ; 204, leaf from a two-year- 

 old sprout. 



Practical Questions 



1 . Tell the nature and use of the stipules in such of the following plants 

 as you can find : tulip tree ; fig ; beech ; apple ; willow ; pansy ; garden 

 pea ; Japan quince (Pyrus Japonica) ; sycamore ; rose ; paper mulberry 

 (Broitssonetia). 



