u 



PLANT STUDIES 



Fig. Zfi. A l)ranching hair from the leaf of common mullein. The whole plant has a 

 felt-like covering composed of such liairF. 



comparatively thick, althougli tliey may l)c very minicrons 

 (see Figs. 4, 173). In this way each leaf exposes a small 



surface to the dry- 

 ing air anil intense 

 sunliglit. Ill our 

 soiitlnvestern dry 

 regions the cactus 

 abouiiils. ]ila. nts 

 which have reduct'd 

 their leaves so much 

 that they are no 

 longer used for 

 chlorophyll \\ ork, 

 and are not usually 

 recognized as leaves. 

 In their stead the 

 gloluilar or cyliii- 

 di-ical or flattened 



Via T ARcalefromthcloaf of f^if/^i/if,,/,,, These ^'^'"'^ =y'*-' grcell ;ind 

 BLuhs )v rlap and form a complete c Ntnn^ do leaf WOrk (h^igS. 



