Mougeotia americana Transeau 1918, p. 237 



Filaments slender; vegetative cells 4-5/x in diameter, 40-120/a 

 long, becoming geniculate in conjugation. Zygospores formed in 

 the tube, but extending into both the gametangia; irregularly 

 quadrate, the margins concave or convex, with angles produced 

 and truncately rounded; median spore wall colorless and smooth; 

 13— 24/x in diameter, 18— 32/a long; sporangium membrane becom- 

 ing filled with pectic substance. 



Douglas Lake, Michigan. 



Mougeotia calcarea (Cleve) Wittrock 1872, p. 40 



Vegetative cells 8-14/i, in diameter, 40-280/a long, filaments be- 

 coming geniculate in conjugation. Zygospores formed in the tube 

 but extending into the gametangia; globose or somewhat angular, 

 the wall colorless and smooth; 25-30/a in diameter, or (if angular) 

 22-28;ti in diameter, 30-50/i, long. 



Mich. 



Mougeotia calcarea var. bicalijptra (Wittr.) Transeau 1926, p. 316 



Vegetative cells 10-12/a in diameter, 30-110;ii long; zygospores 

 with thick end walls adjacent to the gametangia, extending into and 

 at times completely dividing the gametangia. 



Mich. 



Mougeotia capucina (Bory) C. A. Agardh 1824, p. 84 



PI. 70, Figs. 5, 6 



Filaments long and slender, forming purplish, cottony masses; 

 vegetative cells 14-21iU in diameter, 70-150- (280) /a long; chloroplast 

 a narrow axial band with 4-6 pyrenoids ( sometimes as many as 12 

 or 16) in a single series. Zygospores formed in the tube but extending 

 into and dividing both gametangia; irregularly quadrangular with 

 concave margins, the wall brownish-violet and smooth; 50-74/a in 

 diameter, 80-lOOfi long; with lamellate pectic substances deposited 

 in the angles of the spore. 



This species is often found fruiting during late summer along lake 

 margins where water has receded. It forms purple films on 

 moist substrates or purple cloud-like masses about the stems of 

 Chamaedaphne. 



A collection of M. capucina from a Splmgnum bog in Cheboygan 

 County, Michigan, showed mature zygospores with minute puncta- 



[300] 



