90 ZYGNEMATACEAE 



Vegetative cells 8-13 )u x 30-140 m; chromatophore usually occupy- 

 ing two-thirds of the cell, with 4-8 pyrcnoids; conjugation scalariform; 

 zygospores formed wholly in the conjugating tube, globose, 13-25 /a in 

 diameter; spore wall brown, thick, smooth; aplanospores obliquely 

 ovoid, 16-20M X 20-24/1. (PI. XIII, Figs. 3-5.) 



United States: Iowa to Massachusetts; south to Louisiana and Florida. 



Widely distributed in Europe; China; Japan; Brazil; Africa. 



4. MouGEOTiA TUBiFERA Tiffany 1934. Trans. Amer. Micros. Soc. 



53, p. 218. 



Vegetative cells 9-10^1 x 90-400/^; chromatophore with 4-12 pyre- 

 noids in a single, more or less irregular, row; conjugation tubes usually 

 greatly elongated ( 10-65 /i.), often spirally twisted and nearly as large 

 as the filaments (7-9 /^ in diameter). Conjugation occurs through the 

 lateral wall of the papillae as well as through the end. Zygospores 

 asymmetrically ovoid, usually showing a greater bulge on one side than 

 on the other, 27-30 /a x 33-45 a^, not including the outer sporangial pectic 

 layer which is 6-12/1 in thickness; sporangium wall smooth, hyaline; 

 spore wall colorless, thicker, smooth. It is not certain that the spores 

 were fully mature. (PI. XIII, Figs. 6-9.) 



United States: Florida; North Carolina. 



5. MouGEOTiA CALCAREA(Cleve)Wittrock 1872. Bih.Kgl.SvensJ{ 



Veiensl{. A /{ad. Handl. 1, p. 40, PI. 2. 



Vegetative cells 8-1 4 /x x 40-280/1; chromatophores with 4-8 pyrc- 

 noids in a single row; cells elongating, becoming geniculate before spore 

 formation; conjugation scalariform; zygospores formed wholly in the 

 conjugating tube or extending into one or both gametangia, globose, 

 25-30 /t in diameter, or angular-globose, 22-28/1 x 30-50/1; spore wall 

 smooth, colorless, or pale yellow; aplanospore globose, lateral to the 

 sporogenous cell, 17-21 /a in diameter, or rarely trapezoid-ovoid, divid- 

 ing the sporogenous cell, 15-20/1 x 20-28/1. (PI. XIII, Figs. 10-12.) 



North America, British Columbia to Greenland; Dakota to Texas and 

 eastward to Newfoundland and Florida. 



Brazil; Europe; North Africa; southern Asia. 



The variety name "bicalyptrata" has been applied to specimens in 

 which the thickness of the end walls of the sporangium is unusually great. 

 In some collections the thick polar walls occur in Hlamcnts among spores 

 with thin uniform walls. Collections may contain only aplanosporic or only 

 zygosporic specimens, while others may contain both in mixture. In Borge's 

 type material for M. sphaerospora I found 2 zygospores similar to those of 

 M. calcarea; moreover, I found no aplanospores resembling those figured by 

 Czurda from Central Tibet as M. sphaerospora. This figure may represent 

 a new species but descriptive details are lacking. 



