CHYTRID1ALES 205 



Parasitic in and causing elongation of the cells of Zygnema sp., 

 United States. 

 Rieth (1956a) suggests the prosorus may be a resting spore. 



IMPERFECTLY KNOWN SPECIES OF MICROMYCES 



? Micromyces echinocystis Linder 



Nat. Mus. Canada Bull., No. 97, Biol. Ser. No. 26, p. 240, pi. 12, figs. A-C, 



pi. 15, fig. B. 1947 



"Prosori ellipsoid, broadly ellipsoid, or more rarely globose, 24-27- 

 (40.5) x 19.5— 21— (27) jjl, subhyaline to yellowish, ornamented with 

 numerous, curved, pointed spines 1.9-3.3 \l long and 1-1.5 u. in diam- 

 eter at the base. 



"Mostly solitary in the cells of Zygnema sp. and Mougeotia sp., 

 not causing any pronounced enlargement of the host cell, although 

 there may be a slight enlargement and some elongation" (Linder, 

 he. cit.). 



Parasitic in Zygnema sp. and Mougeotia sp. (F. slide No. 2709, 

 Type), Canadian Eastern Arctic. 



? Micromyces minimus Linder 



Nat. Mus. Canada Bull., No. 97, Biol. Ser. No. 26, p. 239, pi. 12, fig. E, 



pi. 15, fig. A. 1947 



"Prosori globose, light coloured to deep yellow-brown, of two 

 types: (1) large 10.5-16.5 \x in diameter, ornamented with short, straight, 

 and relatively thick spines 0.5-0.75 [x long; and (2) small prosori 

 7.5 [i. in diameter and smooth. 



"Solitary or several in a cell of Zygnema sp., the infected host cells 

 not inflated, but almost twice as long as the normal host cell" (Linder, 

 he. cit.). 



Parasitic in Zygnema sp. (F. slide No. 2708, Type), Canadian 

 Eastern Arctic. 



This species, Micromyces wheldenii and M. echinocystis were de- 

 scribed by Linder on the basis of spiny cysts discovered in preserved 

 material of algae collected by Polunin. In no instance were sori or 

 sporangia seen. Micromyces minimus bears a strong resemblance to 



