Moore: The study of winter buds 



135 



Miss Ferguson (1904) found in Pinus that the archesporial 

 tissue was not differentiated into the spore-mother-cells until 

 April, thus disproving Coulter and Chamberlain's general state- 

 ment, as well as their special one, in regard to the gymnosperms. 



Chamberlain (1898) says: "The flower buds of Salix pass 

 the winter in the pollen-mother-cell stage/* This general state- 

 ment for Salix is questioned since flower buds of Salix fragilis 

 gathered in November did not follow this rule. In this case the 

 cells of the anther appear to be homogeneous and show no differ- 

 entiation of tissues. 



It follows from these different observations that both leaf buds 

 and flower buds enter the winter in various stages of develop- 



mm. 



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Figure H. Beiuia popuHfolia, Curves of growtli of the buds in length and 



diameter. 



ment. The exact point at which growth is suspended appears to 

 be an inherited characteristic rather than one solely dependent 

 upon climatic conditions. 



We have seen that most buds, as a rule, d^o not increase ap- 

 preciably in size during the winter months. The question that 

 naturally arises is : Are these buds absolutely quiescent from No- 

 vember to February or are they undergoing changes which are not 



apparent externally? 



Pfeffer (1903) claims that the influence of the continued cold 

 of winter seems to have produced in the life of most plants in the 



colder zones a well marked period of rest. 



903) 



