444 



COENOPTERIDEAE 



[CH. 



of protoxylem elements shown by the white patches in fig. D. 

 In this as in other members of the Zygoptereae the main rachis 

 of the leaf gives off four sets of branches in pairs alternately 



B 



( 





I, 



E 



Fio. 308. 



A. Clepsijdropniii antiqua. 



B. Etapteris Scotti. 



C. Diplolabis foreiuis. 



D. Zygopteris primaria. 



E — G. Stauropterii oldhamia. 

 The white patches in the zylem in figs. B — G mark the position of 

 protoxylem elements. 

 (A, after Unger; B — G, after P. Bertrand.) 



from the right and left side of the primary vascular axis. This 

 method of branching of the stele in the primary rachis of 

 several members of the Coenopterideae shows that the fronds 



