OEDOGONIUM. 83 



x 

 



Diameter veg. cells, 18-36 yu 5 3-7 times longer. 

 Diameter supporting cells, 60-65 ^ by 116-140 ju. 

 Diameter oogon., 68-80 p by 78-92 /*. 

 Diameter oospor., 64-73 yw by 74-84 p. 

 Diameter anclrosp. cells, 24-30 /* by 18-25 yw. 

 Diameter stipe dwarf males, 18-22 yw by 60-70 jw. 

 Diameter sperm, cells, 12-14 yw by 10-12 ju. 



Very variable in size ; widely distributed Pennsylvania, 

 New Jersey, Minnesota, Florida, etc. Specimens are pre- 

 served in Wittr. and Nord.'s series, Algae Exsiccatee, No. 

 107, Pennsylvania specimens; and No. 207, New Jersey 

 specimens. 



Plate LXXXII, figs. 1, 2, filaments of larger form ; fig. 3, 

 male plant ; figs. 4, 5, filaments of smaller form. 



Usually fringing rootlets along the shores of ponds, sticks 

 and the like, but found also in quantity on the rocky shores 

 of lakes in New Jersey. 



OEDOGONIUM ACROSPORTJM, D. By. 



Idio-androsporous ; oogonium single, rarely twin, always 

 terminal, ellipsoid; opening by a small, apical deciduous 

 operculum ; oospore manifestly filling the oogonium, mem- 

 brane longitudinally costate ; supporting cell often swollen ; 

 terminal cell of sterile plants, obtuse ; dwarf males curved, 

 seated on the supporting cells, stem or stipe often bi-cellular, 

 long 5 spermogonia 1-2-celled. 



Diameter veg. cells, 10-14 ^ ; 2-7 times longer. 

 Diameter supporting cells, 15-18 // by 2-3 times longer. 

 Diameter oogon. , 30-35 /* by 45-51 //. 

 Diameter dwarf males, inferior cell, 9-12 jw by 24-32 /*. 

 Diameter dwarf males, superior cell, 6-8 /* by 55-65 yw. 

 Diameter sperm, cells, 6-8 ^ by 14-15 yw. 



The above is Wittrock's description of the European 

 plant. Our United States plants are not altogether iden- 

 tical. One form we may distinguish as 



Var. FLOEIDENSE, Wolle. 



It is nearest the European form, but differs in having the 

 filaments more slender, and cells proportionately much 

 longer, nearly twice the length. The long dwarf males are 

 characteristic 5 they are seated about the middle of the sup- 

 porting cell and extend beyond the top of the oogonium. 



