48 



STUDIES IN THE VEGETATION OF THE STATE 



its protoplasm may not be able to function properly, and as- 

 similation may be so hindered by a lack of proper protoplas- 

 mic stimuli bhat the plant is unable to get and use as much 

 food as it could in a more favorable habitat. It is no doubt 

 true, that after several generations a plant may fully adapt 

 itself to such a change, and then its higher limit of non- 

 available water mav be due to certain changes in the func- 

 tion and structures of the organs of the plant. 



6. Effects of Soil Texture and Composition on the Limit of 

 Available Water. 



Before entering into a discussion of this subject, a summary 

 will be given of all the results of experimentation which 

 bear directly upon this problem. Since the plants compar- 

 ed grew under similar physical conditions in each in- 

 stance where the different soils are compared, it is not con- 

 sidered necessary to give with any table the data for the 

 physical factors. 



The following averages are from five species, viz : 

 Helianthus annuus, Hordeum vulgare, Phaseolus vulgaris, Bicinus 

 communis, and Zea mays, all grown in the plant house. 



Comparative Plot III. 

 Average of Thirty Pots. 



