THE GREEN ALGAE OF NORTH AMERICA 251 



figs. 6-9. Larger, spines of the oospore longer and denser; 

 antheridiuni pluricellular. 



Florida. 



The distinctions between Oe. echinospermum and Oe. pungens 

 were given under the latter species ; the var. horridum has 

 quite a different appearance from the type, and when better 

 known may prove to be a distinct species. 



47. OE. IRREGULARS Wittrock, 1870, p. 128; Wolle, 1887, 

 p. 79, PI. LXXVIII, figs. 4 and 5 ; Hirn, 1900, p. 202, PI. 

 XXXIII, fig. 207. Dioecious, nannandrous ; oogonia single, 

 globose or subdepressed-globose, pore superior ; oospore globose, 

 filling the oogonium, membrane smooth ; stiff ultory cell not 

 swollen ; dwarf males straight, near or on the oogonium ; an- 

 theridiurn exterior, i-4-celled. 



veg. cell, 15-20 /JL diam., 2^-4 diam. long. 



oog., 37-45 M " 36-47 M long. 



oos., 36-42 /x " 34-41 /x " 



nan. stipe, 12-15 M " 20-24 /j. " 



anth. cell, 10-12 /* " 6-8 ^ " 



Florida. Northern Europe. 



This species is in habit much like the monoecious Oe. fragile ; 

 the globose oogonia often occur throughout a long vegetative 

 filament, with only one or two vegetative cells between ; the 

 short dwarf males are usually at right angles to the filament. 



48. OE. ARMIGERUM Hirn, 1900, p. 203, PI. XXXIII, fig. 

 208. Dioecious, nannandrous ; oogonia single, subglobose, 

 pore superior ; oospore globose, almost filling the oogonium ; 

 epispore with subulate spines ; suffultory cell similar to other 

 veg. cells ; dwarf males curved, on the suffultory cell, stipe not 

 seldom 2-4-celled ; antheridium exterior i- (or more- ?) celled. 



veg. cell, 9-11 M diam., 4-10 diam. long, 



oog., 29-33 M " 3 2 -35 /" long, 



oos., 26-29 fj. " 26-29 M " 



lower cell, nau. stipe, 7-8 M " 20-24 M " 



upper cell, nan. stipe, 4.5-6 ^ " 21-30 /* " 



anth. cell, 5-6 M " 7-8 n " 



So. America. 



This species and the following, Oe. echinatum, are notably 

 smaller than our other species with spinous spores ; Oc. echina- 

 tum is larger than Oc. armigenim, with more spherical oogonia 

 and oospores ; the spines are, moreover, rather conical than 

 aculeate. The only reason for including Oe. annigcncm here is 



