8 



GENUS PALLAVICINIA 



the conducting tissue is absent, and there is no connection between it and 

 that of the older shoot from which the branch has arisen (Fig. 2, B). 



Fig. 



region 



!. P allavicinia Z oiling eri. 

 of a frond, showing rhizoids, 



and two ventral 



D. 



Part of the basal 



branches, r. 

 Median longitudinal section of the base of a shoot passing through a young 



ventral branch. The conducting tissue of the main shoot and the branch 



are not continuous. 

 A ventral shoot (r) growing from the surface of the frond of an antheridiai 



plant. The remains of an antheridium may be seen upon the dorsal surface. 

 The apical region of the shoot shown in C. x, the apical cell. 



E. Apical region of a ventral shoot. 



The other initial cells may never develop beyond cutting off a small 

 number of segments. These groups of cells may be recognized for a 

 long time on the surface of the shoot, near its base. Sometimes, how- 

 ever, one or more of these cell-groups resume activity, and from them 



