378 Wuist: BRANCHED PROTHALLIA 
Woodsia obtusa (Spreng.) Torr.—All the cases of branched 
prothallia of Woodsia obtusa were observed on distilled water 
cultures; in two cases branching was dichotomous while in the 
other three cases it was monopodial. Fic. 12, B, shows the 
branch originated from the first cell of the filament. In FIG. 12, 
A, the branch originated from the slightly developed cell plate. 
Fic. 12, C, D, shows different stages in the development of the 
dichotomous branches. Fic. 12, E, was an interesting case of 
branching. Here the wall which cuts off the branch from the 
main filament did not form at the usual place, but formed almost 
in the center of the filament cell which gave rise to the branch. 
Fic. 13. Branched prothallia of Scolopendrium vulgare Sm., X 125- 
Scolopendrium vulgare Sm.—All cases of branching in this genus 
were observed on Prantl’s solution with CaSO, omitted. Fic. 13, 
A-E, shows typical examples of the types of branching found in 
these cultures. Fic. 13, A, is interesting as showing the tendency 
of both the second and third cells of the filament to form mono- 
podial branches with very short cells. In Fic. 13, B, the branch 
which originated from the third cell of the filament formed im- 
mediately a plate of cells which in turn showed a tendency to 
