78 



AGRICULTURE ON THE PACIFIC SLOPE 



FIG. 41. Branch of geranium 



which the stomata are found does not become wet 



(leaves of iris, black- 

 berry, sheep sorrel, 

 poplar, cabbage, and 

 many others). 



These coverings 

 of wax, varnish, or 

 hairs also help to 

 keep water from 

 escaping from the 

 leaf. Notice how 



well buds are protected from drying up by such 



coverings. The 



coverings are not, as 



generally supposed, 



for protection 



against cold. 



Some leaves roll 



up on hot days (corn 



and grasses). This 



checks escape of 



water by making a 



smaller surface for 



the sun and air to 



act on. 



Leaves that stand 



upright (iris) or hang 



down (eUCalyptUS Or FlG . 4 2. Branch of chestnut. 



