186 



to the mother filament grows out as a prolongation; after some 

 time this again is bent outwards and a new branch continues the 



Fig. 145. Castagnea Zostene (Mohr) Thiir. 



a, summit of assimilation-filaments transformed to plurilocular sporangia ; 



b, longitudinal section of the thallus ; c, unilocular sporangium ; (/, trans- 

 verse section of the thallus. (a, c, d, about 200 : 1 ; i, about 90 : 1). 



growth and so forth. The growth of the filaments is in this 

 way sympodial (Fig. 144 a). Now and then it happens that the 

 lengthening of the filaments also takes place monopodially for 

 some time as the figure shows (Fig. 144 b). 



