218 BURTON EDWARD LIVINGSTON 



(2)* Transpiring power of aerially exposed sur- 

 faces, which depends upon: 

 a.* Extent of these surfaces, 

 b.* Structure of the transpiring parts 

 (frequency of stomata and len- 

 ticels, hairiness, cuticularization 

 of cell walls, etc.). 

 c* The condition of these parts, com- 

 prising : 

 c 1 * Openness of stomata and of lenti- 



cels. 

 c 2 * Water-imbibed condition of the 

 aerially exposed cell walls 

 (their water content). This 

 depends upon: 

 c 2 (1)* The general rate of trans- 

 piration (II, B,2). 

 c 2 (2)* The rate of conduction of 

 water to these membranes, 

 from the regions of supply 

 (I,B,2,(l),b). 



