230 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



3. OE. MAGNUSII Wittrock, 1874, p. 38; Him, 1900, p. 81, 

 PI. II, fig. 14: Wittr. and Nordst., Alg. Exsicc., No. 109. 

 Ditfecious ; oogonia single, rarely 2, depressed-globose, pore 

 median ; oospore same form as oogoninm and fully filling it, 

 with triple membrane ; median pitted, others smooth ; anther- 

 idia up to 8-celled ; spermatozoid single. 



veg. cell, 7-10 /u diain., 1/^-4 diain. long, 



oog., 24-27 /j. " 21-26 /JL long, 



oos., 22-25 M " jS-23 M " 



anth. cell, S-IO-M " 5-11 M " 



Mass. Northern Europe. 



4. OE. SUECICUM Wittrock, 18723, p. 5; Hirn, 1900, p. 82, 

 PI. II, fig. 15. Dioecious; oogonia single, subglobose, rarely 

 ellipsoid-globose, pore median ; oospore globose, nearl}- filling 

 the oogonium ; epispore with subulate spines ; male plants 

 about the same size as the female or slightly smaller ; anther- 

 idium 2-4-?-celled, generally in the upper part of the filament ; 

 spermatozoid single ? ; basal cell elongate, terminal cell obtuse. 



veg. cell, 9-14 M diaui., 3-7 diam. long, 



oog., 32-38 /j. " 18-26 M long, 



oos. with spines, 30-37/1* " 30-37 M " 



auth. cell, 10-12 M " 9-12 /j. " 



Mass. Europe, Australia, 



The only macrandrous dioecious species with spinous oospores. 



5. OE. OBSOLETUM Wittrock, 1874, p. 9; Wolle, 1887, p. 

 71, PI. L,XXIV, fig. 3, PI. LXXVI, figs. 6 and 7; Hirn, 

 1900, p. 83, PI. II, fig. 16. Monoecious; oogonia single, sub- 

 globose or depressed globose, pore slightly above the middle ; 

 oospore globose or depressed-globose, not quite filling the 

 oogonium, membrane smooth ; antheridia 1-3 celled, subepigy- 

 nous ; spermatozoid single. 



veg. cell, 9-15 M diam., 3-5 diam. long. 



oog., 34-39 M " 34-43 ji long. 



oos., 30-34 M " 28-32/11 " 



anth. cell, 8-9 /j. " 12-16 M " 



Pa. Sweden. 



This species and the following are included only on account 

 of Wolle's reference, which is quoted as to this species with a ? 

 by Hirn. The two following species closely resemble it. Oe. 

 obsoletum and Oc. plusiosporum are monoecious ; Oc. cardiacum 

 is dioecious, and of somewhat larger dimensions. Oc. obsoletum 

 generally has longer vegetative cells than the others, and 

 oogonia shorter than their diameter, while Oc. plusiosporum has 



