CEDOGONIUM. 71 



OEDOGONIUM OBSOLETUM, Wittr. (Oe. vernale, Wittr.) 



Oogonia single, globose to depressed globose, opening by 

 a pore above the middle ; oospore same form as the oogonium 

 nearly filling it. Spermogoiiia 1-3 celled, subepigynous ; 

 spermatozoids single. 



Diameter veg. cell, 9-14 ^ ; 3-5 times longer. 

 Diameter oogon., 34-38 }JL by 34-40 //. 

 Diameter oospor. , 31-34 // by 28-31 yw. 

 Diameter sperm, cell, 8-9 // by 12-16 yw. 



Ponds, Pennsylvania specimens imperfect, but probably 

 of this species needs farther research. 



Plate LXXIV, fig. 3. Plate LXXXI, figs. 6, 7. 



OEDOGONIUM FRAGILE, Wittr. 



Oogonia single or twin, globose or subegg-shaped-globose, 

 opening by pore above the middle ; oospore fills the oogo- 

 nium ; sperinogonia 1-3 celled, hypogyiious or subepigy- 

 nous ; spermatozoids twin. 



Diameter veg. cell, 12-17 // ; 4-5 times longer. 

 Diameter oogon., 42-47 /* by 44-50 //. 

 Diameter oospor., 40-44 // by 39-44 }JL. 

 Diameter sperm, cell, 12-15 yw by 10-12 //. 



Ponds and ditches, Pennsylvania. 

 Plate LXXIV, figs. 4, 5, 6. 



OEDOGONIUM ZIG-ZAG, (Cleve.) Wolle. 



Oogonia 2-5 or single, opening by a pore above the middle, 

 globular, oospore filling the oogonium ; spermogonia 2-5 , 

 celled ; a series of spermogonia cells alternating with one, or 

 a series of two or more ooonia. 





Diameter veg. cells, 17-18 /* ; 2-4 times longer. 

 Diameter oogon., 50-51 ^ by 53-54 //. 

 Diameter oospor. , 47-48 /* by 49-50 f*. 

 Diameter sperm, cells, 17 ^ by 10-11 yw. 



Have changed the diagnosis slightly to suit the plant, 

 frequent in Northampton County, Pennsylvania. 



Plate LXXIY, figs. 7, 8, 



