tEDOGONIUM. 77 



Syn. Conferva undulata, Breb. ; Cynatonema confervaceum, Kg. 

 Filaments single, not massed, widely distributed. 



Plate LXXVII, fig. 8, filament with oogonium, dwarf 

 male, and pedicel. 



OEDOGONIUM CATERACTUM, Wolle. 



Idio-androsporous 5 oogonia often terminal, single or twin, 

 obovate globose, subglobose or broadly oval, opens by a pore 

 above the middle ; oospore globose or obovate globose nearly 

 filling the oogonium; aiidrosporangia 2-6 celled, dwarf 

 males unicellular, considerably curved, seated on, or some- 

 times below the supporting cell ; spermatozoids internal. 



Diameter veg. cells, 28-38 ju ; U-3 times as long. 

 Diameter oogon., 55-60 // by 60-75 yw. 

 Diameter oospor., 50-55 /u by 50-60 p. 

 Diameter androsp. cell, 26-30 yw by 10-15 yw. 

 Diameter dwarf males, 10 yu by 65 yw. 



Attached to rocks in rapids below water-fall, Pike County, 

 Pennsylvania. 



Plate LXXXV, figs. 10, 11, 12. 



b. Oospores subellipsoid. 



OEDOGONIUM CYATHIGERUM, Wittr. 5 forma AMERICANA, Wolle. 

 Idio-androsporous ; oogonia single, or two to three seriate, 

 oboviform or ellipsoid, opens by a pore above the middle ; 

 oospores of same form, nearly filling the oogonium ; sup- 

 porting cell slightly tumid ; terminal cells obtuse ; andro- 

 sporangia pluricellular ; dwarf males cyathiform, somewhat 

 curved, seated on the supporting cell or on the oogonia. 



Diameter veg. cells, 17-21 yu; l}-3 times longer. 

 Diameter oogonium, 45-50 yw by 55-63 /x 

 Diameter oospore, 39-40 /.i by 44-46 yw. 

 Diameter dwarf males, 12-15 yw by 50-54 yw. 



Ponds, Pennsylvania. This form is somewhat more slen- 

 der than the type-form ; dwarf males are seated on the 

 oogonia, not on the supporting cells, and the vegetative cells 

 are shorter; but we prefer to retain this name as appro- 

 priate and until more numerous specimens are found. 



Plate LXXXI, figs. 20-22. 



