SPIROGYRA. 217 



tiferous cells much inflated ; zygospore oval, about one-half 

 longer than the diameter, which averages 55 ,u ; length, 80 yw. 



This is probably the first record of the fruiting of this 

 species. Found it in large masses in meadow pools in this 

 vicinity. 



Plate CXXXVI, fig. 1, a frequent appearance of sterile 

 filaments ; spiral bands not universally so wide ; figs. 2, 3, 

 fertile filaments. 



SPIROGYRA NITIDA, (Dill.) Link. 



Diameter of vegetative filaments, 72-78 // ; cells one to 

 three diameters in length ; also longer and shorter before 

 and after division. Chlorophyl bands about 4, making 1-4 

 turns of the spirals ; zygospores elliptic-ovoid, often almost 

 almond shape, li times as long as broad. Germinating plant 

 clavate. 



Syn. Conferva nitida. Dill. ; Conjugata princeps, Yauch. ; Zygnema 

 nitidum, Ag. ; Zygnema rostratum, Hass. ; Spirogyra diluta, 

 Wood. 



Ponds, borders of streams, forms dark green masses, 

 slippery to the touch. 



Plate CXXXVII, figs. 7, 8, sterile and fruiting filaments. 



SPIROGYRA SUB^QUA, Kg. 



Diameter of vegetative filaments, 55- 60 /.i ; cells 1-2 times 

 as long as wide ; slightly swollen ; spirals two, or more rarely 

 three, making each 1-2 turns. Zygospores spherical or 

 broadly ovate. 



Spring waters, Pennsylvania. 

 Plate CXLI, figs. 1, 2, sterile and fertile filaments. 



SPIROGYRA BELLIS, (Hass.) Cleve. 



Diameter of vegetative filaments, 65-78 yu ; cells 1* times 

 (rarely 3 times) as long as broad ; spirals 5-6, making -1 

 turn each. Fructiferous cells not swollen. (Hass. and 

 Cleve say swollen Petit says, often not swollen on the side 

 opposite the conjugated cell.) Zygospore orbicular, de- 

 pressed ( lenticular) with the membrane punctate or porose ; 

 chestnut color. 



Syn. Zygnema belle, Hass. 



The species has something in common with the preceding, 

 8. subaequa, but is separated by filaments slightly larger, 

 spirals more numerous and spores lenticular, not globose. 



