92 



decided influence. A long cold period will cause almost a total 

 stopping of growth, though the fungus responds very quickly 

 again to warmth. The effect of temperature will be very clearly 

 shown in Figure i. Curve B represents the average growth of 

 twenty fungi from June 7 to June 24, while curve A shows the 

 average daily temperature for the same period, the figures for this 

 being obtained from the local weather-bureau office. As will be 

 seen, the temperature cur\e contains a decided depression from 

 June 10 to June 13, showing a cold period. The average tern-, 

 perature ranged from 49° to 56° F. during this period, while during 

 the rest of the time it was between 65° and "J^^ . The effects of 

 this cold period are clearly shown in the lower curve. Growth 































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13 14 15 16 17 18 19 20 21 



24 



FiGURK I. Curve A represents the average daily temperature from June 7 to 

 June 21, 1906, showing a cold period from June 10 to June 13. 



Curve B represents the average daily growth of twenty specimens of Polyporus 

 lucidiis during the same period. The effect of temperature on growth is shown. 



w^as almost at a standstill. Some individual fungi did go through 

 this period of three days without a measurable increase in growth. 

 As to moisture and nourishment, we are unable to form an 

 accurate conception of their influence. The fungus grows on 

 logs and stumps which hold a large amount of moisture for some 

 time. It is hardly probable that the lack of moisture is a factor 

 until the logs begin to dry out in the summer. It may then, and 



