ZYGNEMA. 223 



ZYGNEMA INSIGNE, Kg. 



Diameter of vegetative filaments, 26-30 /* ; cells equal to 

 twice as long as broad. Copulation usually scalariforni, or 

 sometimes lateral, sporiferous cells usually slightly swollen. 

 Zygospore brown, globose ; diameter about 30 yw, or some- 

 what broadly oval, 26 by 32 /*. 



Syn. Tyndaridea insignia, Hass. ; Zygnema tenue, Eab. 



Plate CXLIII, figs. 4-6, sterile and fruiting filaments, the 

 latter with matured spores in part, others forming. 



B. Spor oder m punctate or granulate. 



ZYGNEMA STELLIUM, Ag. 



Forming loose interwoven masses, primarily light green, 

 but later, in time of fruiting, dirty yellow, or brownish. 

 Cells 1-6 times as long as wide. Fructiferous cells more or 

 less swollen. Copulation scalariform. Zygospores oblong 

 or globose. Very variable in size. 



Kirchner suggests the following separation of the different 

 forms, all of them occurring frequently here in smaller 

 ponds, pits, rivers, lakes, etc.: 



1. GENUINUM, Kirch. 



Diameter of vegetative filaments, 25-36 ^ ; cells 1-3 times 

 longer than broad. 

 Plate CXLIII, figs. 7, 8, sterile and fertile filaments. 



2. VAUCHERIA, Ag. 



Diameter of vegetative filaments, 22-26 yu; cells 2 -6 

 times longer than broad. Same as Z. Brebiaaonn, Kg. 



Plate CXLIII, figs. 9-11, two sterile and two fertile fila- 

 ments. 



3. TENUE, Eab. 



Diameter of filaments, 12-22 /* ; cells 1-3 times as long as 

 wide. 



Plate CXLIII, figs. 12-13, sterile and fertile filaments. 



4. SUBTILE, Eab. 



Diameter of filaments, 15-19 yw ; cells 2-4 times as long as 

 wide. Same as Z. ovale, Kg. 

 Plate CXLIII, figs. 14, 15, sterile and fertile filaments. 



5. STAGNATE, Kg. 



Diameter of filaments about 10 yu ; cells 3-4 times as long 

 as broad. 



Plate CXLIII, figs. 16, 17, sterile and fertile filaments. 

 15 



