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Wuist: Branched prothallia 



Asplenium bulbiferuni Forst. — The two examples of branched 

 prothalHa which are shown in Fig. io, A, B, developed on the dis- 

 tilled water culture. In both cases the branches originated after 

 the expanded portion of the prothallia had been formed. In 

 Fig. io, a, the branching was dichotomous. This example is es- 

 pecially interesting as showing the tendency of the prothallium 

 to revert to a filamentous condition at the time of the formation 

 of the filamentous branch. In Fig. io, B, branching was monopo- 

 dial and the branch tended to form immediately a plate of cells. 



Fig. II. A-E. Branched prothallia of Phegopteris polypodioides Fee, X 1251 

 G. Branched prothallium of Poly podium aureum L., X 125. 



Phegopteris polypodioides Fee. — The branched prothallium 

 which is shown in FiG. ii, A, occurred in an uncrowded region of 

 the soil culture while those shown in Figs, ii, B-E, and 12, F, 

 developed in modified Prantl's solutions. Fig. ii, B-D, was 

 found in the Prantl's solution with K2SO4 omitted, while Figs, ii, 

 E, and 12, E, occurred in Prantl's solution from which CaS04 had 

 been omitted. In all cases observed the branching was monopo- 

 dial. In Fig. ii, A, the branch was filamentous in form and 

 originated in the second cell of the filament. Fig. ii, B, shows 



