388 



€ihh : The Study of a Fircone. 



stamens and pistil — for a new innpose. So tlic ilowcrs of 

 ' Pittas pori urn undiilatiun and of the rose have their parts in 

 fives, corresponding with their leaf arrangement in a series of 

 five. Here again, however, it must be remembered that cir- 

 cumstances often change and confuse the issue, and not in every 

 case can the story be easily read. 



If an effort be made to find the perfect series of phyllotaxian 

 numbers in the diagram of the common holly, given above, 

 the result will probably be puzzling. In order to do so it is 

 necessar}^ to break into the series of its leaf-arrangement and 



Shewing the manner of growing exactlv over the first, and the 

 formation of secondary °. ° . "^ 



spirals on a spruce fir- time of its rhythm IS 3, 3, 2, 3, 3, 2, 



(fig. 3), with numbered scales, shewing the order of the hidden 

 spiral which passes through them all, it will be seen that the 

 twenty-second scale stands just above the first, and the com- 

 pression of the cone is brought forcibly forward by that fact, 

 for within that short space the original spiral has made no 

 fewer than eight coils, passing through twenty-one scales in its 

 way. 



Fig. 3. 



Now the fircone is built on just the 

 same genera] principles as these which 

 I have been endeavouring to make 

 clear ; only in its case is the order 

 of its leaves ; that is the coil, if pulled 

 out by the yard so as to shew its true 

 formation, would be seen to pass 

 through twenty-one scales in eight 

 coils before one scale would be found 



[To be continued). 



Naturalist,. 



