Spirogyra Spreeiana Rabenhorst 1863, Algen No. 988 



PI. 77, Fig. 9 

 Vegetative cells 18-21- ( 25 )/i, in diameter and up to 25 times the 

 diameter in length; end walls replicate; chloroplast solitary, mak- 

 ing 1 1/2 to 4 turns, Conjugation tubes formed from the male 

 gametangia only; fertile cells inflated on both sides. Zygospores 

 ellipsoid, median spore wall smooth and yellowish; 30— 36/a in 

 diameter, 55— lOO/x long. 

 Mich. 



Spirogyra stictica ( Engl. Bot. ) Wille 1884, p. 34 

 PL 76, Figs. 5-7 

 Filaments of short or long cells, 38-56;li in diameter, 80-300/x long, 

 with plane end walls; chloroplasts 2-6, straight or making 1/2 turn, 

 Conjugation by geniculate bending of the filaments; connecting 

 tubes not formed; the fertile cells becoming slightly swollen. Zygo- 

 spores ellipsoid; median spore wall smooth; 41-64;u, in diameter, 

 75-118/. long. 



In shallow water of lake margins, and in swamps. Mich., Wis. 



Spirogyra suhsalsa Kuetzing 1845, p. 222 

 PI. 73, Figs. 1-3 



Filaments of slender cells 26-28)u, in diameter, (35)-148/x long, 

 with plane end walls; chloroplast solitary, making lig to 3 turns. 

 Conjugation by tubes from both gametangia; fertile cells becoming 

 shghtly swollen. Zygospores ellipsoid; median spore wall smooth, 

 inner irregularly reticulate (?), and brown; (18)— 33— 35/x in 

 diameter, (30)— 55— 59/x long. 



This species should be compared with S. esthonica (Skuja) 

 Czurda and S. daedalea Lag., from which two species it diflfers in 

 fundamental details of the spore characters. 



In swamps and other shallow water habitats. Wis. 



Spirogyra sueciQa (Borge) Transeau 1934a, p. 420 



Vegetative cells 26-29/. in diameter, 80-175/* long, with plane 

 end walls; chloroplast solitary. Conjugation by tubes from both 

 gametangia; fertile cells inflated on both sides. Zygospores ovate; 

 median spore wall smooth; 32-39/. in diameter, 38-60/i long. 



Mich. 



Spirogyra sulcata Blum 1943, p. 783 



Filaments of rather stout cells 37-46/t in diameter, 50-160/. long, 

 with plane end walls; chloroplast solitary (rarely 2), making 2 to 5 

 turns. Conjugation by tubes from both gametangia, which are 



[321] 



