132 



PLAN DIAGRAMS 



[CH. 



diagrams of these with telling effect, introducing system 

 and order into these difficult cases. 



Fig. 34. A, plan diagrams of a j , and i? of a ? inflorescence of the 

 Birch ; C and D, of s and ? inflorescences respectively of the Alder. In 

 each case the catkin-scale b has a small dichasium of three flowers (the 

 central one * absent in D, however) in its axil. The flowers of the 

 dichasium, of which the central is the oldest, are subtended by bracts a 

 and ^ and bracteoles a' and /3'. It is these bracts which join the catkin- 

 scales and give them their compound character (Ei). 





Fig. 35. Plan diagrams of Chestnut. ^, of a c? lateral shoot with 

 distichous leaves ; jB, of a shoot with spirally arranged leaves and bearing 

 both (f and ? partial inflorescences ; C, of a <? partial inflorescence, show- 

 ing stamens and rudiment of pistil in the primary flower onlj'. D, a ? 



