1904] Relationship between Weather and Plant Growth. 43 



these I found at least two striking" instances. One plant of the 

 common wild strawberry, F. virginiana, was in bloom some ten 

 days before its sister plants in 1902, namely on the i ith of April ; 

 and on the 17th of April, 1903, I found one Canada violet ex- 

 panded, while I found no others anywhere till eight days later, 

 both these plants are still growing and blooming late in the fall; 

 and winter had in this case probably caught both of them in bud, 

 Thus the strawberry, being a perennial, and the Canada violet, 

 protected by the thick snowy garment, acting probably as a win- 

 ter annual, were both ready to proceed and open their blossoms 

 as soon as Winter released his grip. 



To account for the remarkably sudden and rapid advance in 

 the growth of the plants last May, we should naturally infer that 

 there must have been some remarkable phenomenon in the weather 

 of that month. In order, then, to ascertain this accurately and to 

 see whether the conclusions from my observations of the Com- 

 parative Phenology of IQ02 and 1903 were borne out by the Com- 

 parative Meteorology of these two seasons, I, after writing the 

 above conclusions, applied to the weather bureau for a statement 

 of the progress of the weather during the periods named, and 

 particularly ol the temperature and rainfall. These were courte- 

 ously furnished me by the Deputy Minister of Marine. 

 " Comparing first the ^aily maximum temperature for the two 

 seasons, it came out that while the maximum daily temperature of 

 March was just about the same in both years, namely 42.3'' in 

 1902, and 42^ in 1903, yet it was better distributed to stimulate 

 growth in 1902. For, while the first eighteen days were the same 

 in both months, the next two days were unusually cold in 1902 

 and unusually warm in 1903, and consequently the rest of the 

 month, i.e., the last third, the important part for vegetation, was 

 on an average 6.5^ warmer per day in 1902, being 52^ in 1902 

 and 45 5" in 1903. This gave that year a slight advantage at the 

 start, which was seen in the blooming of hepaticas, for example, 

 on the 28th March, 1902, and on the 30th in 1903; and of the silver 

 maple on the abih in 1902 and the 29th in 1903. This slight ad- 

 vantage in favor of iqo2 was increased during the first third of 

 April which was warmer in 1902 by 1.8*^ per day. During the 

 rest of April, 1902 had a slightly higher average daily maximum 



