IN THE POLYPODIACEAE 377 
the origin of the branch from the first cell of the filament and Fic. 
11, D, shows the further development .of this branch into a fila- 
ment of five cells. In Fic. 11, C, is shown an interesting example 
of branching. Here the first prothallial cell instead of dividing 
_ by a transverse wall into two cells, divided by means of a longi- 
tudinal wall, thus forming two cells side by side. One of these 
cells by growth and transverse division continued the growth of 
the filament while the other gave rise to two branches. One 
formed a filament of two cells, the first of which was extremely 
long. In Fics. 11, E, and 12, the branches were not formed until 
E 
A-E. Branched prothallia of Woodsia obtusa (Spreng.) Torr., X 125. 
F. Branched prothallium of Phegopteris polypodiotdes Fée, X 75 
the expanded portion of the prothallia had begun to develop. In 
Fic. 12, the expanded portion later showed a decided tendericy 
to branch monopodially at its apex. — 
Polypodium aureum L.—Only one case of branching was observed 
in this species and it developed on the distilled water culture. As 
shown in Fic. 11, G, the branch originated in the first prothallial 
cell, The rate of growth was the same for both the main filament 
and the branch. 
