94 FRESH-WATER ALGJE OF THE UNITED STATES. 



Diameter veg. cells, 37-45 //; l}-2.} times longer. 

 Diameter oogoii., 61-75 yw by 68-80 p. 

 Diameter oospor., 58-66 yu by 60-65 yw. 



Minnesota, near Minneapolis. 

 Plate LXXVIII, fig. 3. 



OEDOGONIUM LONDIENSE, Wittr. 



Monoecious ? oogoiiia single or twin, globose, cut round in 

 the middle, opening by a pore seated in the fissure ; oospore 

 globose, almost filling the oogoniuni ; spermogonia, or andro- 

 sporangia, 1-2 celled, hypogynous. 



Diameter veg. cells, 10-15 yw; li-5 times longer. 



Diameter oogon. , 33-35 yu by 33-43 yw. 



Diameter oospor., 27-32 yu by 26-32 yw. 



Diameter sperm, cells, 26-27 yw by 27-29 yu. 



Plate LXXV, figs. 7, 8, fruiting filaments found in New 

 Jersey. 



OEDOGONIUM HEXAGONUM, Kg. 



Oogonia almost globose, inclining to hexagonal ; oospore 

 globose, rufous-brown not filling the oogoniuni ; terminal 

 cell obtuse or sometimes setigerous. 



Diameter veg. cells, 11-13 yw 5 2-4 times longer. 



Diameter oogon. 24-25 yu by 26-28 yu. 



Diameter oospor. 16-18 by 16-18 yu. 



Syii. Vesiculifera hexagona, Hass. 



Occasionally intermingled with other species. 

 Plate LXXXI, figs. 18, 19. 



b. Oospores ellipsoid or oval. 



OEDOGONIUM GIGANTEUM, Kg. 



Oogonia single, somewhat tumid, cylindrical -obovate, 

 opening by a pore above the middle; oospore cylindric- 

 ellipsoid or broadly obovate, nearly filling the oogoniuni 

 (sometimes flask-shaped, short-necked,) epispore delicately 

 scrobiculate*; supporting cell somewhat swollen. 

 Diameter veg. cells, 30-42 yu 5 2-4 times longer. 

 Diameter oogon., 57-69 ju by 78-106 yw. 

 Diameter oospor. , 54-65 yw by 75-103 yw. 



A form very nearly related to Oe. capilliforme, Kg., and 

 may be a mere variety of that species. 



Plate LXXVI, figs. 4, 5, 6. 



