358 



BOTANICAL GAZETTE 



[NOVEMBER 



Consequently, low shrubs, and herbs which pass the winter by means 

 of underground stems, are well protected from low temperatures and 

 sudden temperature changes. The ice further results in lowering the 

 temperature in spring and in retarding the beginning of favorable 

 growth conditions. 



The percentage of sunshine is not published by the several sta- 

 tions, but the number of clear and partly cloudy days is stated. The 

 numbers from the various stations show marked differences, due to 

 different standards established by the observers; but perhaps these 

 are largely eliminated in the average. If we take the average num- 

 ber of clear days, add to it one-half the number of partly cloudy days, 

 and divide by the number of days in a year, we obtain a percentage 

 of forty- six. This probably approximates the percentage of sunshine. 



In comparison with the rainfall data for Halifax and St. John, it 

 is notable that in the latter localities the mean rainfall, both monthl) 

 and annual, is considerably larger. The annual precipitation 

 exceeds that of the Huron valley by fully 20 inches (50 cm ), or about 

 40 per cent. Finally, the sunshine percentage is slightly lower, being 

 39 for Halifax and 42 for St. John. 



Temperature. The following table exhibits the monthly and 

 annual means for the several stations already cited : 



MEAN TEMPERATURE IN F. 



The table shows that the temperature conditions are compara- 

 tively uniform throughout the basin. The maximum average tem- 

 peratures occur in July and August. But the significance of the data 

 becomes more apparent, in so far as the bog vegetation is concerned, 

 when they are compared with those of St. John and Halifax (fig. 3). 

 It is to be noted that, although the average temperature for June, 



