LAGENIDIALES 



967 



grew her isolate on agar in petri dishes the cells did not separate, but if 

 later the plate became slightly dry the cytoplasm dissociated into several 

 olpidioid sporangia. Vishniac points out that the widespread occurrence 

 of this phenomenon among fungi and the ease with which it can be 

 manipulated makes its use as a generic character rather dubious. 



Fig. 77. Sirolpidium bryopsidis (de Bruyne) H. E. Petersen 



A. Portion of filament of Bryopsis showing an early stage in development 

 of fragmenting type of thallus. B. Olpidioid sporangia discharging their zoo- 

 spores. C. Fragmenting thallus each part of which becomes a single sporangium. 



D. Tip of filament of Bryopsis showing a group of olpidioid sporangia. 



E. Thallus fragmenting; cell at extreme left has already discharged its zoo- 

 spores. F. Long discharge tube produced by thallus. G. Thallus fragmenting; 

 traces of original thallus wall are seen connecting the parts. H. An olpidioid 

 sporangium discharging its zoospores, and, at right, zoospores which were 

 killed with osmic acid and stained with fuchsin to show flagella. /. Inter- 

 pretation of zoospore (enlarged, freehand drawing). 



(Sparrow, 1934c) 



