IX THE POLYPODIACEAE 



371 



Adiantum helium Moore. — Branched prothallia in the various 

 species of Adiantum studied occurred only on the distilled water 

 cultures. In Fig. 6, A, is shown the only case of branching which 

 was observ^ed in A. helium. Here the filamentous branch origi- 

 nated in the first cell of the filament. 



Adiantum. Capillus-Veneris L. — Examples of branching among 

 the prothallia of this species were frequently observed. In all 

 cases the branching was monopodial and in the majority of cases, 

 as showTi in Fig. 6, B-G, the branches developed from the second 

 cell of the filament. FiG. 6, C-E, shows the manner of develop- 



FiG. 6. A. Branched prothallium of Adiantum bellum Moore, X I75- B-G. 

 Branched prothallia of A. Capillus-Veneris L., X 125. H. Branched prothallium of 

 A. cardiochloena Kunze, X 125. I-L. Branched prothzXlia. oi A . cunealum Langsd. 

 & Fisch., X 125. 



ment of the branch and likewise the continued growth of the main 

 filament. In Fig. 6, F, no filament had been developed; the 

 second cell divided to form the beginnings of the expanded portion 

 of the prothallium. From this expanded region the branch was 

 given off. 



Adiantum cardiochloena Kunze. — Fig. 6, H. Here the branch 

 developed from the cell which was cut off by the formation of a 

 vertical wall in the second cell of the filament. 



