THE GREEN ALGAE OF NORTH AMERICA 429 



14. V. PILOBOLOIDES Thuret in Le Jolis, 1863, p. 65, PI. 

 I, figs. 4 and 5 ; Worouin, 1869, p. 153, PI. II, figs. 18-29; P- 

 B.-A., No. 476. Marine; filaments usually 40-60 // diam., 

 sometimes 80 /j. ; antheridium terminal, separated from the fil- 

 ament by an empty cell, cylindrical, acute, with one or two 

 lateral, conical projections ; oogonium terminal, usually on a 

 short branch near the antheridium, clavate with a spherical 

 summit, up to 200 //. diam. ; oospore lenticular with thin mem- 

 brane, 150X80-100 /u. ; aplanospores 250X80 /x., formed at the 

 ends of the branches, expelled from the sporangium at maturit) 7 . 

 Muddy and sandy places, below low water mark. Conn. 



Var. COMPACTA Collins, 1900, p. 13; P. B.-A., No. 477. 

 Tufts very densely matted ; oospores usually spherical, occa- 

 sionally lenticular ; oogonia and antheridia scattered without 

 definite relation to each other. Salt marshes, on mud near high 

 water mark. Mass. 



The dense, plush-like coatings of this variety are indistin- 

 guishable from V. Thitretii, that grows in similar locations ; but 

 the fructification is quite distinct. 



15. V. SPHAEROSPORA Nordstedt, i878a, p. 177, PI. II, 

 figs. 7 and 8 ; Phyk. Univ. , No. 282. Marine; filaments 25-60 

 /j. diam., loosely tufted ; antheridium at the somewhat swollen end 

 of a branch, generally slightly curved, acuminate, bearing just 

 below the summit two conical, subopposite processes ; oogonium 

 below on the same branch, separated by an empty cell, globose 

 or obovoid-globose, 105-135 /u. diam. ; oospore green, with thin 

 membrane, 85-125 p. diam., not filling the oogonium. Green- 

 land. Northern Europe. 



16. V. INTERMEDIA Nordstedt, ,1879, p. 179, PI. I, figs. 

 10-16 ; Wittr. & Norclst., Alg. Exsicc., No. 334. Marine; fila- 

 ments 35-65 fj. diam. ; oogonia subsessile or shortly pedicelled, 

 globose or ovoid-globose, 90-130 /* long, 95-115 ^ wide, with one 

 short and broad tube ; antheridium single or often two, 20-30 //. 

 diam., usually straight with rounded, truncate apex, and 2-4 

 very short, lateral tubes; oospore globose, with thin membrane, 

 85-120 /u. diam., almost filling the oogonium. Greenland. 



Northern Europe. 



17. V. CORONATA Nordstedt, 1879, p. 177,- PI. I, figs. 1-9; 

 Wittr. and Nordst., Alg. Exsicc., No. 1022. Marine; filaments 

 48-70 p. diam. ; oogonia solitary, subsessile, borne on the branches 

 bearing the antheridia, more rarely on the main filaments, 

 obovoid or obliquely ovoid, 125-145 /u. long, 145-180 p. wide, 

 bearing at the top a circle of 3-6 tubes for the entrance of the 

 spermatozoids ; oospore globose or subglobose, 115-135X115- 



