CLIMATE AND PLANT GROWTH. 



59 



Oak-brush 



Aspen 



Sprue e-F/ ', 



Evaporation 



;.- — Temperature above 4-0° F 



Average stem length 



Dry weight per p/ant 



Leaf iength 



l/Vater used per p/ant 



Pig. 32. — Comparison between climatic factors and the growth of wheat. 



