SPIROGYRA. 1 207 



25. S. fluviatilis, Hilse. 



26. S. nitida, Link. 



27. S. subsequa, Kg. 



28. S. jugalis, DHL 



29. S. setiformis, Roth. 



30. S. dubia, Kg. 



31. S. adnata, Kg. 



32. S. rivularis, Rab. 



33. S. majuscula, Kg. 



34. S. elongata, Berk. 



35. S. parvispora, Wood. 



ZYGOSPORES LENTICULAR, ORBICULAR DEPRESSED. 



36. S. orthospira, Naeg. 



37. S. bellis, Hass. 



38. S. maxima, Hass. 



39. S. crassa, Kg. 



SECTION I. MEMBRANE OF CELL REPLICATE AT 



BOTH ENDS. 



A. One spiral, or rarely two in a cell, 

 a. Membrane of spore smooth. 



SPIROGYRA TENUISSIMA, (Hass.) Kg. 



Diameter of vegetative cells 9-12 /* ; 4-15 times longer 

 than broad; ends inlaid; single spiral, making 3-6 turns. 

 Spore, 24-30 /t by 50-58 /J. Sporiferons cells much swollen, 

 about twice as long as the spore. Zygospore oblong-elliptic, 

 yellow or brown at maturity. 



Syn. Zygnema tenuissima, Hass.; Rhynclionema minimum, Kg.; 

 Spirogyra Naegelii, Kg. 



Ditches and pools. The smallest of our Spirogyra; 

 varies considerably in size, even more than indicated by the 

 measures given. 



Plate CXXXII, figs. 1-3, fruiting and sterile filaments, 

 a Wiynclionema form. 



SPIROGYRA INFLATA, (Vauch. ) Rab. 



Diameter of vegetative filaments, 14-18 JJ ; cells 3-8 times 

 longer than broad ; cells with spore very much inflated ; 

 spiral single, makes 3-8 turns. Fruiting cells much inflated, 

 zygospore fusiform-elliptic, diameter 30-36 yw ; twice as long 

 as wide. 



14 



