THE GREEN AI.GAE OF NORTH AMERICA 257 



the other ; Oc. Borisianum has smooth spores ; Oc. concatcnatum 

 has dotted lines on the median membrane of the oospore, but 

 the outer membrane and the oogonium are smooth. One form 

 and one variety are to be noticed. 



Forma INSIGNE (Nordstedt) Hirn, 1900, p. 222, PI. XXXVII, 

 fig. 227. Stouter, lines on the oospore and oogonium 35-40, 

 oogonia i-io, androsporangia to lo-celled, antheridia i-4-celled. 

 The dimensions are one-fourth or one-fifth larger in all parts 

 than in the typical form. N. J. Sweden. 



Var. CONCINNUM Hirn, 1900, p. 222, PI. XXXVII, fig. 228. 

 Smaller ; oospore not quite filling the oogonium ; lines on the 

 membrane of the oospore finely crenulate. The dimensions are 

 about one-tenth smaller than in the type. 



Minn. 



58. OE. CONCATENATUM (Hass.) Wittrock, 1874, p. 25; 

 Wolle, 1887, p. 81, PI. L,XXIX, figs. 1-3, and var. sctigeruni 

 Wolle, 1887, p. 82, PI. LXXIX , figs. 4 and 5 ; Hirn, 1900, p. 

 223, PI. XXXVIII, fig. 230. Dioecious, nannandrous, gynan- 

 drosporous ; oogonia single or 2-6, suboviform or quadrangular- 

 ellipsoid, pore superior ; oospore same form as the oogonium, 

 nearly filling it, membrane apparently triple ; outer membrane 

 smooth, median membrane with pits, more or less distinctly ar- 

 ranged in 30-35 longitudinal series, inner membrane smooth ; 

 suffultory cell swollen; androsporangia i-4-celled; basal cell 

 elongate, terminal cell obtuse ; dwarf males curved, on sufful- 

 tory cell ; anthericlium exterior, i-4-celled. 



veg. cell, 25-40 Mdiam., 3-10 diatn. long, 



suf. cell, 50-62 fj. " 1%-2'A " " 



oog., 63-83^ " 76-105 ^ long, 



oos., . 60-76 p. " 67-95 M 



andr. cell, 25-28 /j. :t 15-36 M " 



nan. stipe, 17-25 M " 50-75 M 



anth. cell, 13-15 M " 12-25 M " 



Mass., N. J., Pa., Alaska. Europe. 



Various forms of this species are found in Europe, but only 



the type has been recorded in this country. The distinctions 



between this species and the three preceding have been already 



indicated. 



59. OE. MULTISPORUM Wood, 1869, p. 141 ; Wolle, 1887, p. 

 78, PI. LXXX, figs. 6 and 7 ; Hirn, 1900, p. 232, PI. XXXIX, 

 fig. 239. Dioecious, nannandrous ; oogonia single or 2-3, sub- 

 oviform or subglobose (pore superior ?) ; oospore globose, nearly 



