LOSS OF WATER ' 29 



petiole may take on the character of the blade, and perform 

 all its functions, as in the case of various acacias. In certain 



Fig. 20. — Tulip bulb; longitudinal section. F, solid stem; B, flower 

 bud; S, leaf-bases serving as bud-scales, and also for the storage of plant 

 food. 



leaves nothing remains but base, petiole, larger veins, and 

 the lips of the blade, as in the New Zealand raspberry 



Fig. 21. — Buds of the tuhp-tree {Liriadendron tulipifera), showing stipules 

 as bud-scales.. (Photo by the author.) 



(Fig. 18). In some plants, as for example, the grasses 

 (Fig. 22), there is no distinction between petiole and blade. 



