Second Blooming of Snowball 271 



Therefore, it is to be observed, that, during the second anthesis the num- 

 ber of clusters was greatly reduced, and the size of the individual cymes 

 was much less. 



Ordinarily V. opuhis blooms in the early summer so that in this 

 case about two months or more must have elapsed between the first and 

 the second anthesis. Certain other species of this genus may be "forced" 

 to bloom by the addition of heat during cold weather. 



Regarding the second blooming of plants in the same season we 

 have various suggestions as to its cause. If branches of certain plants 

 are allowed to project into a warm greenhouse during the winter, these 

 branches will develop transpiring leaves although the remainder of the 

 plant may be outside in low temperature. This shows that water is 

 still absorbed by the roots and passed through the stem." Some plants 

 under such conditions are unable to absorb water from a frozen soil and 

 hence wilt.' Kerner' observed that a root of a Clematis plant growing in 

 cold air and frozen developed leafy stems when a branch was conducted 

 into a hothouse. The food substances made in the summer were available 

 for use as soon as deposited". He says further: "The same must indeed 

 be the case in those plants which bloom normally in the spring, but yet 

 often in years characterized by particularly mild autumns, burst open in 

 October, the buds destined for the next spring thus sending out fresh 

 leafy shoots and blossoms twice in the same year — for example, — many 

 apple and horse chestnuts, violets and strawberries, many primulas, gen- 

 tians and anemones." So in the case of the second blooming of the snow- 

 ball here discussed, a rather high temperature might have influenced the 

 plant to renew fruiting activity. Reference to the local weather bureau 

 records shows that the temperature ran high during the second blooming 

 of this plant. This influence of temperature on the second blooming of 

 plants is upheld by an account by Darwin and Shrubbs entitled "Records 

 of Autumnal or Second Flowerings of Plants". They enumerate 75 

 such plants in England and further state: "It can hardly be doubted 

 that these second flowerings are connected with relatively high tempera- 

 tures'". 



Recently an account of an eight to nine year old cherry tree near 

 Bloomington, in full bloom for the second time in the same season, came 

 to the notice of the writer. Here again the high temperature prevailing 

 during the second blooming of this tree indicates strongly the close con- 

 nection between high temperature and the second seasonal blooming of 

 plants. 



= Pfeffer, W. Phvsiology of Plants. Enslish Edition Vol. 1, p. 231. 

 ' Kerner, H. and Oliver, T. W. English Edition. Vol. 1, p. 564. 



* Darwin, Frances and Shrubbs, A. Records of Autumnal or Second Flowerings of 

 Plants. The New Phytologist 1922. Vol. 21, p. 48. 



