132 



DESCRIPTIVE BOTANY. 



Examples of various Forms of Divergence among cer 

 tain Species of the following Genera, selected from n 

 long List given by M. Braun. 



(128.) Mode of examining the Divergence. To the 

 above list we will add a complicated example, in the 

 spinous bractese which compose the 

 involucrum of Carduus Eriophorus, D 

 and explain the manner in which 

 the divergence may be ascertained. 

 It is easy to observe two sets of 

 spirals respectively parallel to A B 

 and CD (fig. 142.), of which there 

 are 34 of the former, and 21 of 

 the latter. Fixing the Nos. 1, 35, 

 (J9, in one direction, and 90 in 

 the other, as in art. 124., we ar- 

 rive at the bractea which ranges vertically over No. 1. 



