110 



HISTOLOGY AND PHYSIOLOGY. 



Diatoms and some of the higher Sea-weeds (FucaeecB, 

 FlorideoR) flourish. Of our ordinary land plants, subjected 

 to dififerent temperatures, the greatest growth of the 

 plumules took place as follows : 



Pea 78.8° F. 



Wheat 92.7° F. 



Indian Corn 92.7° F. 



Scarlet Bean 92.7° F. 



In other experiments it was found that the most rapid 

 growth of roots was at the following temperatures : 



Scarlet Bean 78.8° F. 



Pea 79.9° F. 



Flax 81.3° F. 



Wheat 83.3° F. 



Indian Corn 92.7° F. 



The following table shows the lowest (minimum), the 

 most favorable (optimum), and the highest (maximum) 

 degree of temperature at which seeds of several plants will 

 germinate : 



Seeds. 



Indian Corn 

 Scarlet Bean 

 Pumpkin 

 Wheat . 

 Barley . 

 Flax , . 

 Pea, . , 

 Hemp . . 

 Watermelon 



Minimum. Optimum. Maximum 



48.8° F. 

 48.8° F. 

 56.7° F. 

 41° F. 

 41° F. 

 35° F. 

 43° F. 



92.7° F. 

 92.7° F. 

 92.7° F. 

 83.7° F. 

 83.7° F. 

 81° F. 

 80° F. 

 88.7° F. 

 99.5° F. 



115.2° F. 

 115.2° F. 

 115.2° F. 

 108.5° F. 

 99.5° F. 



Metastasis may take place at lower temperatures than 

 assimilation. In the growth of many plants in spring, at 

 the expense of the reserve material, metastasis takes place 



