38 STUDIES IN THE VEGETATION OF THE STATE 



It may be well to give the results from two other grasses 

 in addition to the previous ones, the physical conditions be- 

 ing similar. 



Panicum orus-galli. 



Average of 5 plants, Apr. 5 to Apr. 17. . . 

 Average of 5 plants, Apr. 17 to Apr. 29. 



6.6 

 6.2 



PLANT 

 VFATEK 



29.3 

 33.1 



Ghaetochloa glauca. 



Average of 6 plants. Mar. 9 to Apr. 1. 

 Average of 6 plants, Apr. 1 to Apr. 29. 



7.5 

 7.1 



29.8 

 26,2 



The results from these grasses indicate that the increase 

 of light and heat was favorable to the plants, increasing 

 their ability to take water from the soil. The winbe" condi- 

 tions of the plant house were shade conditions, and as the 

 light increased the plants became more and more vigorous; 

 the heat increased at a more rapid ratio than the light, but 

 in case of the grasses did not become excessive while the 

 plants were dying, the physical conditions being similar to 

 those of Comparative plot II. 



EFFECT OF TEMPERATURE BELOW THE NORMAL. 



Since the normal or optimum temperature may vary with 

 the habitat of the plant, the results obtained by growing 

 plants of different habitat under a certain range of temper- 

 ature fluctuations are apt to vary with different plants. Case 

 I contained plants of three species, \\z.,Zea mays, Phaseolus 

 vulgaris, and Eordeum vulgare, grown in loam, loess and sand, 

 at a temperature usually varying from 5° to 20° below that of 

 the other cases. The following results from Case I and 

 Case III, will show the effects of a slightly lowered temper- 

 ature as compared with those of the normal in raising or 

 lowering the limit of physiological water. The averages are 

 taken from thirty plants in each case. 



