FUNGI: SAPROLEGNIA. 



123 



thread of the mycelium. In other cases large portions of the threads of the 

 mycelium may separate into chains of cells. Both these kinds of cells are 



Fig. 133- 

 A mucor (Rhizopus nigricans) ; at left nearly mature sporangium with columella showing 

 within; in the middle is ruptured sporangium with some of the gonidia clinging to the colu- 

 mella ; at right two ruptured sporangia with everted columella. 



capable of growing and forming the mycelium again. They are sometimes 

 called chlamydospores. 



Water Moulds (Saprolegnia). 



279. The water moulds are very interesting plants to study 

 because they are so easy to obtain, and it is so easy to observe a 

 type of gonidium here to which we have referred in our studies 

 of the algae, the motile gonidium, or zoogonidium. (See appen- 

 dix for directions for cultivating this mould.) 



280. Appearance of the saprolegnia. — In the course of a 

 few days we are quite certain to see in some of the cultures deli- 

 cate whitish threads, radiating outward from the body of the fly 

 in the water. A few threads should be examined from day to 

 day to determine the stage of the fungus. 



281. Sporangia of saprolegnia. — The sporangia of saprolegnia 

 can be easily detected because they are much stouter than the 



