204 AQUATIC PHYCOMYCETES 



relative, M. intermedia, in having more sporangia in a sorus and in 

 having a smooth, colorless prosorus wall. 



RECENTLY DESCRIBED TAXA J 



Micromyces grandis Miller 

 J. Elisha Mitchell Sci. Soc, 71 : 247, figs. 1-29. 1955 



"Prosorus 30.4-51.2 [x (most about 40.0-48.0 \x) in diam., with a 

 thickened hyaline wall, covered with many (17-25) long, sharp spines, 

 38.4-67.2 u, (most about 51.2-60.6 \x) in length; spines usually curved 

 at their ends; contents of the prosorus with many highly refractive 

 globules grouped towards the center; as the host cell becomes mori- 

 bund, germinating to form a globose sorus at first slightly smaller than 

 the prosorus; swelling to about 1/5 again the size of the prosorus as 

 its contents divide into many (33-54) zoosporangia; zoosporangium 

 pyramidal in shape, with a rounded to polygonal base and a truncated 

 apex, 9.6-1 1.2 (j. x 16.0-23.1 {j.; contents of zoosporangium dividing 

 into many zoospores; soral membrane splitting along the lines of cleav- 

 age of the bases of the zoosporangia, releasing them; occasionally 

 the soral membrane not splitting, the zoosporangia remaining in the 

 intact sorus; zoospores ovoid, with a single globule of oil and a single 

 posteriorly directed flagellum, 2.1-2.8 (average about 2.3) u, in diam., 

 escaping from the sporangia and swimming through the ruptured host 

 cell wall; resting bodies, yellow-green to golden-brown, 16.0-32.0 \x 

 in diam., the walls thickened, outer layer averaging 1.4, the inner 

 1.1 [x in thickness; outer wall invested with 20-24 short spines; resting 

 body functioning as a prosorus" (Miller, he. cit.). 



In cells of Spirogyra sp. (North Carolina), United States. 



Micromyces ovalis var. giganteus Sparrow and Barr 



Mycologia, 47: 546, fig. 21. 1955 



"Prosorus hyaline to light yellow, ellipsoid, 36-40 \x long by 16-21 y. 

 in diameter, bearing six circular rows of spines, 4-6 u, long; sorus, 

 sporangia and zoospores not observed" (Sparrow and Barr, be. cit.). 



1 Not included in the key. 



