LOSS OE WATER 



41 



becomes a real source of danger to the plant. Indirectly, 

 however, transpiration performs a great service, for it 

 aids in, and is probably one of the chief causes of, the 

 ascent of Kquids taken in from the soil. Were water 

 never given off, it would not be possible for tissues, 



Fig. 32. — Sempervivum tabulaforme. The arrangement of the leaves 

 in a compact rosette, the hairs on their margins, their thick cuticle, and 

 other characters, make the plant xerophytic or drought-resistant. (Photo 

 by the author.) 



EClready turgid, to receive a fresh supply, and, since all 

 the elements of plant-food can be carried through the 

 plant only in solution, the importance of this point can 

 hardly be overestimated. 



, The manner in which transpiration may facilitate the 

 passage of Hquids through the stem may be illustrated 



