IN THE POLYPODIACEAE 



373 



verse wall to form a filament of two cells, cut off by two oblique 

 longitudinal walls, a branch cell on either side. FiG. 8, B, C, 

 shows similar cases, however in Fig. 8, B, the second instead of the 

 first prothallial gave rise to the branches. In Fig. 8, C, both the 

 second and third cell each gave rise to a branch while the third 

 cell of the filament continued the growth of the prothallium. In 

 Fig. 8, D, the branch cell which developed from the first prothallial 

 cell divided immediately to form the beginning of a plate of cells. 

 The branched prothallium shown in Fig. 8, E, is in a much more 



Fig. 8. Branched prothallia of Camplosoriis rhizo phyllus L. 

 E. X 75- 



A-D, X 125; 



advanced stage of development. Here a filament of four cells was 

 formed, then a plate of cells developed. From this plate, early 

 in its development, a lateral branch was cut ofT which in turn 

 formed an expanded prothallium. The original plate of cells 

 continued its growth into a broad prothallium which showed a 

 decided tendency to branch at its apex. 



Asplenuim Filix-femina (L.) Bernh. — The branched pro- 

 thallia of A. Filix-femina were observed on both the soil and 

 distilled water cultures. Fig. 9, A, B, developed on the distilled 

 water cultures and Fig. 9, C, on the inner surface of the pot 



