PLANT ASSOCIATIONS 131 



FARMLAND 



Cultivation, with Wheat. 



Upland Cultivation, without Wheat. 



Upland Cultivation, with occasional Wheat. 



One point of great interest is the effect that one plant may have 

 on others, as indicated by the effects of a beech- wood, for instance, on 

 the undergrowth. 



Since the above was written, Mr Francis J. Lewis, to whom we 

 are indebted for one of our illustrations, has published some further 

 contributions* towards the study of plant distribution in this 

 country. 



* The Geographical Journal, May 1904. 



