78 FRESH-WATER ALG^E OF THE UNITED STATES. 



OEDOGONIUM MULTISPORA, Wood. 



Oogonia single, bi- or tri seriate, globose with a distal 

 lateral pore ; oospore globose about the same size as the 

 cavity of the oogonium. Dwarf males (antheridia) bi- or 

 tri -cellular, curved with the lower part much the largest, 

 generally adhering in considerable numbers to all parts 

 of the female plant. 



Dr. Wood remarks : " This species differs from its nearest 

 European congeners, Oe. Rothii and Oe. tlepressum, very 

 markedly in the bi-cellular antheridia," He gives no meas- 

 ures ; the plant illustrated, Plate LXXX, figs. 6, 7, is from 

 the vicinity of Philadelphia, and supposed to be the plant 

 referred to. The oogonia are not only tri- but often MUL- 

 TISPORA. 



Diameter veg. cells, 12-15 yu ; 2-3 times longer. 

 Diameter oogon., 45-50 yw by 45-50 yu. 

 Diameter oospor., 42-47 yu by 42-47 yw. 

 Diameter sperm, cells, 11-13 yw by 40-50 yw. 



Plate LXXX, figs. 6, 7. 



B. Species with dwarf males bi-multicellular, spermogonia external. 



A. Oospores with smooth membrane. 



a. Oospores globose or subglobose. 



/ 



OEDOGONIUM FLAVESCENS, (Hass.) Wittr. 



Idio-androsporous, oogonia single, egg-shaped-globose or 

 hexagonally globose, opening by a pore in the middle or 

 a little above the middle, oospore globose, not filling the 

 oogonium ; androsporangia 1-9 celled ; dwarf males slightly 

 curved, seated on the supporting cell ; spermogonia usually 

 one-celled. 



Diameter veg. cell, 18-21 yw ; 4^-6 times longer. 

 Diameter oogon. , 49-52 u by 51-60 yw. 

 Diameter oospor., 45-49 yu by 45-49 yu. 

 Diameter androsp. cell, 17-20 yu by 8-18 yw. 

 Diameter stipe dwarf male, 11-12 >w by 39-45 yw. 

 Diameter sperm, cell, 9-10 // by 15-20 yu. 



Syn. Vesiculifera flavescens, Hass. 



Minnesota, near Minneapolis. 



Plate LXXVIII, figs. 1, 2, filaments with oogonia, dwarf 

 males, etc. 



