by scalariform conjugation, not dividing the gametangia; globose 

 or broadly ovate; walls smooth and golden brown; 25-31/x in 

 diameter, 27-40fx long. 



In littoral flora of many lakes. Mich., Wis. 



Moiigeotia sphaerocarpa Wolle 1887, p. 227 

 PI. 74, Fig. 6 

 Vegetative cells 19-24;li in diameter, 60-120- (240) /a long; chloro- 

 plast with 4-6 pyrenoids. Zygospores formed variably, sometimes 

 dividing one or both gametangia; subglobose to ovate; median spore 

 wall brown and smooth; 40-45/a in diameter, or 36-40,u in diameter 

 and 40-55/A long. 

 Mich. 



Mougeotia tumidula Transeau 1914, p. 297 

 PI. 71, Fig. 2 

 Vegetative cells long-cylindric, 6-8/i, in diameter, up to 120/a long; 

 chloroplast a broad plate with 4-8 pyrenoids in one series. 

 Zygospores formed in the tube, dividing both gametangia; quadran- 

 gular; both inner and outer spore walls minutely scrobiculate; 

 22-26/x in diameter, 26-30/^ long. 

 Mich. 



Mougeotia varians ( Wittr. ) Czurda 1932, p. 79 

 PI. 71, Figs. 11, 12 



Vegetative cells 25-27/x in diameter; chloroplast a broad band 

 entirely filling the length of the cell, with 4 pyrenoids. Zygospores 

 formed in the tube, dividing one of the gametangia; cylindric or 

 drum-shaped, the free walls concave, the walls adjoining the 

 gametangia convex; median wall smooth and brown; 48-60/1, in 

 diameter, 60-70- ( 78 ) ^t long. 



This species is smaller than M. laetevirens (A. Braun) Wittr. 

 and also differs in that the zygospore completely fills the gametangial 

 cell, whereas in M, laetevirens the spore is formed entirely within 

 the conjugation tube. 



In the tychoplankton of soft water lakes. Mich., Wis. 



Mougeotia ventricosa (Wittr.) Collins 1912, p. 69 



Vegetative cells 5-8-(9)/a in diameter, 100-140/x long. Zygospores 

 unknown. Aplanospores obliquely ellipsoid to subglobose; median 

 spore wall yellow and smooth; 12-24/x in diameter, 16-29/i long. 



Mich. 



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