PHYLLOTAXIS. 



37 



2. ARRANGEMENT OF LEAVES ON THE STEM OR 

 PHYLLOTAXIS. 



The various modes in which leaves are arranged on the 

 stem are called Phyllotaxis. 



Leaves are produced either singly at a node, as in the 

 Mume and Sakura (Fig. 39), or two or more at the same 

 node in the form of a whorl, as in the Aokiba (Aucuba 

 japcmica) (Fig. 41) and Yayemugura ; the formre land of 

 phyllotaxis is said to be Scattered or Unimerous, and the 

 latter Polymer -ous. 



, I Unimerous. 



Arrangement of leaves \ „ . 



{ Polymerous. 



The scattered leaves are ordinarily produced on the stem 

 with elongated internodes, as in the Mume and Sakura 

 (Fig. 39) ; but in some cases they are developed on a 



Fig. 39. 



Fig. 40. 



Fig. 39. — Shoot of the Sakura 

 with alternate leaves. 



Fig. 40.— Shoot of the Megi 



(Berberis Thunbergii), 



with fascicled leaves. 



a Spine. 



