CHYTRIDIALES 207 



? Micromyces sp. Canter 

 Trans. Brit. Mycol. Soc, 32: 84, fig. 9. 1949 



Prosorus brownish, spherical to subspherical, 6-22 \l in diameter, 

 with a thick hyaline, smooth or spiny wall; sorus approximately equal 

 in diameter to the prosorus, smooth-walled, divided at maturity to 

 form 4-8 broadly pyramidal sporangia 12-15 (jl high by 8-3(?) u. broad 

 containing numerous posteriorly uniflagellate uniguttulate zoospores 

 2 [jl in diameter; resting spore not observed. 



Parasitic in Mougeotia sp., Great Britain. 



This fungus was discussed by Canter in connection with Micromyces 

 zygogonii. It differs in having two types of prosori: some with lower 

 spines than in that species and others that are smooth-walled. Unlike 

 M. zygogonii, it is confined to a single species of host, does not produce 

 hypertrophy, and causes a blackish residue of host material to collect 

 at the cross walls of the infected cells. (See also remarks under 

 ? Micromyces minimus, p. 205). 



PHLYCTIDIACEAE 



Thallus epi- and endobiotic, monocentric, eucarpic, the epibiotic 

 cyst either expanding and becoming an inoperculate sporangium, a 

 prosporangium, or a thick-walled resting spore and the endobiotic 

 part functioning as the vegetative system, or the cyst not enlarging 

 and either evanescent or persistent, in which case the endobiotic part 

 forms the reproductive organ as well as the vegetative system; zoo- 

 spores posteriorly uniflagellate, generally with a single globule; sexual 

 reproduction, where known, by fusion of aplanogametes borne in 

 thalli; resting spore upon germination functioning as a sporangium 

 or prosporangium. 



Primarily parasites and saprophytes of fresh-water algae, micro- 

 scopic animals, and submerged pollen grains. 



The family includes the greater part of the fungi commonly re- 

 ferred to as "chytrids" and corresponds roughly to the "Rhizidiaceae" 

 (excluding Rhizidium and its close allies) of most monographers. 



