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



The net-like marking of the spores is found in some other 

 species, but the only one with which there is any danger of mis- 

 take is Oe. scrobiculatum , which can be distinguished by being 

 dioecious, and having ellipsoid spores. 



14. OE. GENICULATUM Hirn, 1898, p. 28 ; 1900, p. 106, PI. 

 VIII, fig. 48 ; P. B.-A., No. 411. Monoecious ; oogonia single, 

 slightly swollen, oboviform or oboviform-globose, pore superior ; 

 oospore not filling the oogonium, globose or sub-depressed- 

 globose, sometimes appearing subquadrangular ; membrane 

 thick, smooth; antheridia i-5-celled, subepigynous, subhypo- 

 gynous or scattered, often alternating with vegetative cells. 



veg. cell, 37-48 /a, diatn., i>-3 diam. long. 



oog., 56-63 AI " 56-67 /u long. 



oos., 48-59 M " 48-59 n " 



anth. cell, 37-44 M " 5-9 p " 



California. 



Noticeable in this species is the fact that the oogonia pro- 

 ject but little beyond the vegetative cells ; a few other species 

 are similar, but they are all dioecious. 



15. OE. CAPILLIFORME Kiitzing, 1849, p. 367 ; Wolle, 1887, 

 p. 88, PI. LXXV, figs. 11-13; Hirn, 1900, p. 107, PI. VIII, 

 fig. 49 ; Rourneguere, Alg. Exsicc., No. 685, as Oe. cap i Hare. 

 Dioecious; oogonia single, slightly swollen, oboviform or sub- 

 oboviform, pore superior ; oospore ellipsoid-globose or cylin- 

 drical-globose . and appearing quadrangular, sometimes with a 

 slight constriction at the middle, more rarely globose or sub- 

 globose, not filling the oogonium, membrane smooth ; male 

 plant slightly more slender than the female ; antheridia 2-5-, 

 rarely lo-celled, often alternating with the vegetative cells ; 

 spermatozoids binate,, division horizontal; basal cell elongate, 

 terminal cell obtuse or apiculate. 



veg. cell, female, 28-38 M diam., 1/^-3 diam. long, 



veg. cell, male, 25-30 M " J ^-3 " " 



oog., 42-50 n " 51-62 fj. long, 



oos., 37-45 /x " 40-50 n " 



anth. cell, 20-25/4 " 8-10 M " 



Reported by Wolle, but questioned by Hirn as to being of the 

 type. From St. L,ouis, Mo., is recorded a forma valida, one- 

 seventh to one-tenth larger. 



Var. AUSTRALE Wittrock in Wittr. and Nordst., Alg. Exsicc., 

 No. 704; Hirn, 1900, p. 109, PI. IX, fig. 52; P. B.-A., No. 

 1189; Oc. princeps Wolle, 1887, p. 93, PI. LXXVIII, fig. 3 ; 



