38 



COMPARATIVE MORPHOLOGY OF FUNGI 



pierces the host membrane by an emission collar and emits amoeboid 

 zoospores. 



In winter this germsphere is transformed as a whole into a thick- 

 walled hypnospore (Fig. 22, 2) which germinates in the spring with 

 zoospores liberated through an emission collar. Thus in Diplophlyctis, 

 the whole development is shifted one step further into the host cell than 

 in Rhizidiomyces. Pseudolpidiopsis Schenkiana, parasitic on Zygne- 

 maceae, is systematically placed differently by various authors. Lotsy 

 (1907) and Minden (1915) have placed it in the Olpidiaceae, although 

 the original author, Zopf (1885, p. 169) expressly stated that in contrast 



\ j, 





Fig. 22. — Diplophlyctis intestina. 1. Fresh point of infection. The zoospore mem- 

 brane has disappeared by solution. The germ sac has formed a short rhizoid which is about 

 to swell to an apophysis at its point of attachment. 2. Thick-walled hypnospore with 

 apophysis. Pseudolpidiopsis Schenkiana. 3. Fresh infection. The zoospore membrane 

 has already gelified and the germ sac is about to swell to form a zoosporangium. 4, 5. 

 Germinating zoosporangia. 6. Copulation of a small male and large female. 7. Germi- 

 nating hypnospore; the male is still recognizable as an empty sac. (1, 2 X 600; 3 to 7 X 

 200; after Zopf, 1885.) 



to the Olpidiaceae, no naked protoplast penetrates the host cell and, 

 therefore, he classed it in the Ancylistaceae. Whether it belongs to the 

 Ancylistaceae or Rhizidiaceae will depend mainly on the number of flagella 

 and type of fertilization. If the zoospores are uniflagellate, as Fisch 

 and Zopf state, they belong to the Rhizidiaceae. If they are biflagel- 

 late and if fertilization is oogamous, as Scherffel (1925) states, they belong 

 to the Ancylistaceae. The latter solution is also suggested by its similarity 

 to dwarf specimens of Myzocytium. 



As soon as the zoospores reach the host, they surround themselves 

 with a membrane and put forth a germ tube which swells to a germ sac 

 within the host cell. This matures to a zoosporangium while the swarm 



