JOHANSON: MYCELIOCHYTRIUM 105 



lar, or frequently gibbose ; dehiscing by rupture or deliquescence of the sporan- 

 gial wall. Zoospores Usually arranged in linear rows, giving sporangia charac- 

 teristic appearance, spherical, 1.3-2 p. with a minute, .5 n refractive globule; 

 flagellum approximately 11 ^ long; frequently swarming in sporangium, and 

 emerging singly or in rows as sporangium swells and ruptures. Walls of 

 sporangium and remainder of rhizomycelium reacting negatively to cellulose 

 tests. 



Saprophytic on vegetable substrata, chitin, and keratinized substrata in 

 Connecticut, New York, Pennsylvania, New Jersey, Virginia and Louisiana, 

 U.S.A., Amozonas and Matto Grosso, Brazil. 



This species was first observed by Professor Karling in 1936 from material 

 collected in New Jersey, but he did not observe zoospores and did not pursue 

 his studies any further. It was rediscovered by the author in material from 

 New York in 1944, and since that time Professor Karling found it as a 

 saprophyte on various substrata in Amozonas and Matto Grosso, Brazil. 

 Thus, it appears to be widely distributed in soil and water throughout the 

 Western Hemisphere. 



Since its resting spores are not definitely known, the taxonomic position 

 and relationships of M. fulgens are not certain. As was noted earlier, the 

 thallus lacks intercalary swellings and tapering rhizoids, characteristic of most 

 polycentric chytrids, and resembles the mycelium of the higher fungi. There- 

 fore, its inclusion in the family Cladochytriaceae at the present time is subject 

 to question. Doubtless other similar fungi will be discovered in the future, 

 and as our knowledge of the chytrids is extended the relationship of M. fulgens 

 will become clearer and more certain. 



The author wishes to express her gratitude to Professor John S. Karling 

 for helpful criticisms and to Dr. Edwin A. Quain, S.J. for the Latin diagnoses. 



Department of Botany 

 Columbia University 



