206 AQUATIC PHYCOMYCETES 



the species of Micromyces described by Canter (1949c: 84) in con- 

 nection with M. zygogonii (see p. 195). Both fungi have two types of 

 prosori, the one covered by low straight spines and the other having 

 smooth walls. In Linder's material the smooth-walled prosori were 

 distinctly smaller than the spiny and both types were found together. 

 In Canter's, they were approximately equal in size except for a single 

 case (op. tit., fig. 9 j) in which the two occurred in the same cell. The 

 smooth-walled one was noticeably smaller. Her fungus did not attack 

 Zygnema, the host of Linder's species. Whether in both instances one 

 is dealing with variation in wall ornamentation within a single species 

 or with a mixed infection is uncertain. 



? Micromyces spirogyrae Skvortzow 



Arch. Protistenk., 51 : 433, fig. 6. 1925 

 Synchytrium spirogyrae (Skvortzow) Karling, Mycologia, 45: 278. 1953. 



Prosorus spherical or ellipsoidal, with a thick wall, the outer sur- 

 face densely covered with slender rodlike isodiametric spines 3.5-3.8 u, 

 long; sorus, sporangia, and zoospores not observed; resting spore 

 22.5-26 [x long by 18—22.5 [jl wide, with a thick brown wall, densely 

 covered with spines, germination not observed. 



In Spirogyra inflata, Skvortzow (be. cit.), Manchuria; Spirogyra 

 sp., Litvinow (1953:77), Latvia. 



The true affinities here cannot be determined until the zoospores 

 have been observed. 



? Micromyces wiieldenii Linder 



Nat. Mus. Canada, Bull., No. 97, Biol. Ser. No. 26, p. 240, pi. 12, fig. D, 



pi. 15, fig. C. 1947 



"Prosori light coloured to yellow-brown, globose, 22.5-30 u, in diam- 

 eter, covered by a spiny membrane, the spines hyaline, up to 2 u, 

 long, straight, bluntly or sharply pointed, and arising from the coloured 

 subhemispherical bases. 



"Solitary in Zygnema sp., causing a globose or elongate-ellipsoid 

 enlargement of the host cell" (Linder, be. cit.). 



Parasitic in Zygnema sp. (F. slide No. 2716, Type), Canadian 

 Eastern Arctic. 



