t)ixoN AND Atkins — Osmotic Pressures in Plants. 



457 



Table YI. 



Bedera helix : Leaves from south aspect. 



Considering that the specimens grew under such totally different condi- 

 tions of illumination and moisture, the seasonal variation in the concentration 

 is remarkably similar. The osmotic pressure of the leaves of both, like 

 those of Ilex, shows a decided average increase in autumn, winter, and spring, 

 and a corresponding drop in the summer. The plant in the northern aspect 

 had its maximum in March and its minimum in August. The specimen from 

 tlie south aspect was extremely similar, except that the crest in March was 

 slightly exceeded by a rise in January. The magnitude of the osmotic 

 pressures also approximated to those of Ilex. 



