SPIROGYRA. 221 



Distributed in flowing waters from New York to Florida, 

 forming lubricous, darker or yellowish green masses. 



Syn. Zygnema rivulare, Hass. 



Plate CXXXVI, figs. 4, 7, sterile and fertile filaments. 



SPIROGYRA MAJUSCULA, Kg. 



Diameter of vegetative filaments, 54-62 /* ; cells 2*-10 

 times as long as broad; chlorophyl bands light green, 3-5, 

 sometimes more, as many as 8-10 ; usually lax ; fruiting cells 

 not inflated, 2-4 times longer than wide. Zygospore oval 

 or subgiobose. 



Forming often large, lubricous masses in ponds or pools, 

 pale yellow green, or light greenish yellow. Not rare. 



Syn. Spirogyra orthospira, Naeg. 



Plate CXXXVII, figs. 1-4, two sterile and two fertile fila- 

 ments. 



Plate CXLII, figs. 5, 6, a singular and extraordinary 

 freak. Two filaments of distinct species, the one 8. majus- 

 cula, and the other 8. calospora (&. protecta, Wood,) in conju- 

 gation. Prof. C. E. Bessey, in the American Naturalist for 

 January, 1884, describes an instance of this kind observed 

 by himself. Apparently a hybridism between two distinct 

 forms ; the one with one spiral and infolded ends of cells, 

 the other with numerous spirals and obtuse ends. 



SPIROGYRA ELONGATA, (Berk.) Kg. 



Diameter of filaments, 22-30 yu; cells 4-14 times longer 

 than broad ; spirals two, or more rarely three, lax, describ- 

 ing 3-4 turns in a cell. Fructiferous cells much inflated ; 

 diameter of elliptic or oval zygospore somewhat greater than 

 that of the vegetative cell. 



Pools and ditches, Pennsylvania. 



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



SPIROGYRA PARVISPORA, Wood. 



Diameter of vegetative filaments, 75 yu ; cells 2-4 times 

 longer than broad ; spirals four narrow bands, making each 

 about 1J turns; zygospores very small, elliptical, li-2 times 

 longer than broad, diameter 50 yw. 



Dr. Wood reports this form from the Pine Barrens, near 

 Hibernia, Florida. It is remarkable for the comparatively 

 small size of the spores. 



Plate CXL, figs. 8, 9, sterile and fertile filaments. 



