10 

 2. Old withered leaved cling to plants and protect lauds, just as 

 man protects tender plants with straw, etc. Such protection does 

 not exclude intense cold "but makes it less sudden in its approach. 

 The danger from heat is not so much the burni ng of the tissue hut 

 the danger of excessive transpiration. The danger from cold is 

 not so much the danger from freezing b-at the impossibility of the 

 roots to supply the moisture lost by transpiration. 



