450 



Bulletin 279. 



rainfall, accompanied by a large amount of sunshine. In 1906 there 

 was less sunshine but an abundant rainfall, which was well distributed, 

 thus bringing about conditions favorable for the growth of timothy. 

 In 1907 the larger amount of sunshine in June combined with an ex- 

 tremely low rainfall tended to produce drought conditions during the 

 latter part of the growing season. 



/'^^^ 



/^(?S 



/^(?<$ 



/-^o?. 



Fig. 139. Curves for temperature and rainfall at Ithaca, 

 N. Y., from August, 1904, to July, 1907. 



Place variation in earliness. — The variation from year to year in earli- 

 ness of bloom is shown graphically in Fig. 140. It Mall be seen that the 

 season was much later in 1907 than in either of the two preceding years. 



The range of variation is practically the same for the three years, but 

 the distribution is somewhat different, resulting in a change of modal 

 position. This is probably due, to a large extent at least, to climatic 

 conditions since blooming is often delayed by unfavorable conditions 

 of temperature and humidity. If one of these unfavorable periods is 

 immediately followed by highly favorable conditions, a large number 



