SPECIES OF ALGJE. 49 



II. KEY TO THE FRUITING PLANTS OF VAUCHERIA. 



Antheridia slightly bent; the opening at top (a). 

 " bent like a horn or hook (d). 



" not known (g). 



a. Oogonia nearly round (b). 



a. " not round; oval, often rather oblique (c). 



b. Oogonia about ioo// in diameter dichotoma, 149 



b. " 125-120/1 " " Thuretii, 149 



c. Oogonia 1-6, on one side, mouths lateral, produced beak-like, 



sericea, 150 



c. " erect, mouths not lateral, not produced beak-like, 



aversa, 149 



d. Antheridia beside or between the subsessile oogonia (e). 



d. Antheridia terminal, with the oogonia on each side or lower 



down (/). 



e. Terrestrial, broadly expanded; antheridia bag-shape or clavate, 



Dillwynii y 150 



e. Aquatic; antheridia short and straight, or elongate and variously 



curved sessilis, 151 



/. Terrestrial only; antheridium long, curved, oogonia on its back, 



terrestris, 153 

 /. Not strictly terrestrial; fruit on short lateral branchlets, 



geminata, 151 



f. " " fruit on short segments on the divided 



ends of branchlets hamata, 152 



g. Branches regularly constricted at base and often elsewhere, 



tuber osa, 154 

 g. Branches not constricted; filaments 180-200;* in diameter, 



pilus, 153 



31. BOTRYDIUM. 



One species granulatum, 155 



32. VOLVOX. 

 One species globator, 158 



33. EUDORINA. 



One species stagnate, 160 



34. PANDORINA. 



One species morum, 161 



