40 SPECIES OF ALGjE. 



V. Diameter of veg. cells 13-14/* ... ... pyriforme, 95 



V. " " " " i6-2o/t . . ... irregulare, 79 



V. " " " " 27-30/i . . \ . . . . crrssiusculum, 80 



w. Oogonia opening by a pore {x). 



w. " " " " lid (aa). 



X. Pore above the middle (y). 



X. " below " " oospore with 4 spiral ridges . Huntii, 85 



y. Oospore longitudinally costate . . .... Wolleanum, 82 



z. Diameter of oogonia 45-50/* by 60-75/* • ■ • Boriseanum, 81 

 z. " " " 70-83/t by 90-105/* . . . concatenatum, 81 

 z. " " " 29-32/* by 33-38/* .... sexangulare, 82 



aa. Oospore longitudinally costate, filling the oogonium, 



acrosporum, 83 

 aa. " not " " (dd). 



bb. Terminal cell setiform . ciliatum, 84 



bb. " '' not setiform obtruncatum, 84 



cc. Oospores ellipsoid oogonia opening by a pore in the middle, 



Hystrix, 87 

 cc. " globose (dd). 



dd. Oogonia opening by a pore at the middle . echinospermum, 86 

 dd. " " " " " above the middle {ee). 



ee. Spines of oospores conical (//). 



ff. Diameter of veg. cells 2.5-5 times as long as wide . stellatum, 85 

 ff. " " " " 1-2 times as long as wide . Donnellii, 85 



ff. " " " " 6-14 " " " " " . echinatum, 86 



gg. Oogonia not or scarcely swollen (hh). 

 gg. " manifestly swollen («). 

 hh. Diameter of oospore 22-52/* by 38-62/* .... capillar e, 87 



hh. " " " 47-49/* by 50-66/* .... stagnale, 87 



ii. Oospores globose or subglobose (/z). 

 a. " ellipsoid or oval {pd). 



jj. Oogonia opening by a pore (kli). 



jj. '• " " " lid; oospore globose , . Fringsheimti, 90 



- kk. Pore in the middle; membrane of veg. cells and of oogonia spirally 



punctate .... . . . . . . puncto-striatum, 90 



kk. Pore in the middle; membrane not punctate . . rufescens, 89 

 kk. Pore above the middle (//). 



//. Oospore filling or barely filling the oogonia (mm). 

 II. Oospores not filling the oogonia (nri). 



mm. Oospore globose, filling the oogonium, diameter 25-29/t by 24-30/* 



Franklinianum, 89 



