92 FRESH-WATER ALG^ OF THE UNITED STATES. 



male plant slightly thinner than female ; spermogonia 5-25 

 celled ; spermatozoids binate, terminal cell obtuse. 



Diameter veg. cells, fern., 33-36 yu; 4-6 times longer. 

 Diameter veg. cells, mas. , 21-33 yw. 

 Diameter oogon., 63-75 /u by 105-120 /x 

 Diameter oospor. , 59-70 yu by 75-102 yw. 

 Diameter sperm, cells, 27-30 yw by 9-12 /x 



Syn. Vesiculifera LandsborougM, Hass. ; Oe. gemelliparum, 

 Hantzsch. 



Pond, near Elmira, New York. 

 Plate LXXXI, figs. 8-11, two female and two male plants. 



OEDOGONIUM RIVULARE, (Led. ) A. Br. 



Oogonia single or 2-7 seriate, obovate, opening by a pore 

 above the middle; oospore obovate, rarely ellipsoidal or 

 subglobose ; very much smaller than the cavity of the 

 oogonium; the male somewhat smaller than the female 

 plant ; spermogonia 3-9 celled ; spermatozoids binate. 



Diameter veg. cells, fern., 35-45 yw; 3-7 times longer. 

 Diameter veg. cells, mas., 30-36 yw; 4 times longer. 

 Diameter oogon., 70-85 yu by 130-160 yu. 

 Diameter oospor., 55-65 yu by 65-100 yu. 

 Diameter sperm, cells, 21-28 yu by 14-16 yw. 



Syn. Prolifera rivulare, Led. 



Florida, Iowa. 

 Plate LXXXIII, figs. 1, 2, female and male plants. 



Var. MAJOR, Wolle. 



Oogonia single, or in series of 2-3, broadly elliptic or 

 oval, opening by a pore above the middle ; oospore oval, 

 nearly filling the oogonium. 



Diameter veg. cells, 55-70 yu ; 2-5 times longer. 

 Diameter oogon., 90-100 yw by 130-150 yu. 

 Diameter oospor. , 70-75 // by 120-125 yw. 



The largest of our Oedogoniums, unlike the typical form ; 

 not in matured fruiting condition ; occurring frequently in 

 waters of Florida. Seems nearest to Oe. rivutare. 



Plate LXXYI, figs. 7, 8 ; Plate LXXXIII, fig. 9, prob- 

 ably belongs to the same variety. 



