WORK OF THE LEAVES: TRAJXSPI RA 



Ipl 



where there are dry currents of air. These can be compared 

 with others where the air is quiet and the soil is 1 kept moist. 

 Plants with thick, leathery leaves, like the rubber plant or the 

 purslane, can be set in a dry room along with plants with thin 

 delicate leaves to compare the result. The purslane will some- 

 times grow if it is hung on the fence. It is a kind difficult to 

 kill. Trees and shrubs with thin leaves usually shed them on the 



Fig. 87. 



Rhododendron maximum during mild weather in the winter, leaves expanded and extend- 

 ing out laterally in normal position. 



approach of winter, since water transpires from them rapidly. 

 Evergreen trees have thick and hard leaves with a strong cuticle. 

 They lose water slowly. Interesting observations can be made 

 on rhododendrons, which are often grown in city parks or in 

 private grounds. In extremely cold weather when it is freezing, 

 the rhododendron leaves hang downward and are rolled up into 



