202 



PLANT RELATIONS. 



Fig. 174. Two species of A chillea on different soils. The one to the left was grown 

 in drier conditions and shows an abundant development of hairs.— After 



SCHIMPEK. 



extreme of leaf reduction has been reached by the cactus 

 plants, whose leaves, so far as foliage is concerned, have 

 disappeared entirely, and the leaf work is done by the 



