202 AQUATIC PHYCOMYCETES 



ered with short sharp spines, splitting into three parts; other phases 

 not observed. 



In Spirogyra sp., United States. 



Differing from Micromyces cristata in being of smaller size and 

 bearing sharp spines on the sorus wall. 



Micromyces laevis Canter 

 Trans. Brit. Mycol. Soc, 32: 87, fig. lOb-g, pi. 10, figs. 6-8. 1949 

 Synchytrium laevis (Canter) Karling, Mycologia, 45: 278. 1953. 



"Prosorus spherical, 7.6-18 u, in diameter, with a smooth colourless 

 wall; sorus endobiotic, smooth walled, spherical, with four to eight 

 sporangia; soral wall splitting into as many parts as sporangia, zoo- 

 spores [oval] numerous, 1 \l in diameter, with a single oil globule, 

 and posterior flagellum. Resting spores, 12.7 [a. in diameter, brown 

 walled, rarely covered with numerous short fine hairs; on germination 

 functioning as a prosorus" (Canter, loc. cit.). 



In Mougeotia sp., Canter (loc. cit.), Great Britain; Rieth (1956a: 27, 

 figs. 1-10, pi. 1), Germany. 



Micromyces fischeri (Scherffel), comb. nov. 



Micromycopsis fischeri Scherffel, Arch. Protistenk., 54: 208, pi. 10, fig. 77. 

 1926. 



Prosorus ovoid, 12 by 17 to 25 by 40 \x, to spherical, 8-12 jx in 

 diameter, densely granular, brownish, with a large eccentric oil glob- 

 ule, a thick smooth wall, discharge tube cylindrical, usually not ex- 

 tending beyond the surface of the outer wall of the host; sorus spheri- 

 cal, compound, 8-20 u, in diameter, with a thin smooth colorless wall, 

 sessile on host cell, brownish at maturity, rarely sessile on the endo- 

 biotic prosorus, divided into two to sixteen segments by somewhat 

 radially arranged sutures, the whole cut off by a wall from the dis- 

 charge tube; each soral segment forming five sporangia ("primary 

 zoospores"), 4.3 by 2.4 \x, with an anterior mass of oil and a posterior 

 flagellum, movement jerky and amoeboid, forming after encystment 

 two to six posteriorly uniflagellate ("secondary") zoospores, 2 u. in 

 diameter which swim actively; other characters unknown. 



