Classification 1^1 



There is little, if any, justification for the inclusion of the Tetrasporacese (especially as 

 constituted by Oltmanns) in the ' Volvocales,' and it is very doubtful if the Volvocinese 

 have sufficient claims to be removed from the Protococcales and elevated to a group of 

 equal rank (the ' Volvocales'). The ' Halosphseracese,' established to include Halosphsera 

 and EremospJi&ra, is purely artificial, as everything known concerning these Algfe indicates 

 that they are in no way nearly related. There seems little need for the ' Scenedesmacese, 3 

 which if Dictyosphxnum 'be excluded, is equivalent to the Autosporacese (the ' Protococ- 

 caceae Autosporese' of Chodat) and also with very slight differences is synonymous with 

 Blackman & Tansley's ' Selenastracese.' Oltmanns' inclusion 'of the CEdogoniacere within 

 the Ulotrichales is in striking contrast to his whole-hearted acceptance of the Heterokontse 

 as a primary group ; and his use of the name ' Protococcaceso ' is not altogether in 

 agreement with its origiiml meaning, but is in part synonymous with the modern 

 conception of the Chlorochytriacere ( = Endosphseracese). The Vaucheriaceaa is retained 

 within the Siphonales. In outline the arrangement is as follows : 



Heterokontx. 



Families : Chloromonadacese ; Confervacete ; Botrydiacere ; Chlorotheciaceae. 

 Afotittv (Zygophyceae). 



n. Conjugate. 



Families : Mesotreniacete ; Zygnemaceae ; Desraidiacete. 



b. Bacillariacese. 

 ( 'hlorophycex. 



a. Volvocales. 



Families : Polyblepharidacece ; Chlorodendraeese ; Chlamydomonadacese ; 

 Phacotacese ; Volvocacese ; Tetrasporace*. 



b. Protococcales. 



Families : Protococcaceae ; Protosiphonacea: ; Halospheeraceaj ; Scenedes- 

 maceae ; Hydrodictyacese. 



c. Ulotrichales. 



Families : Ulotrichaceaj ; Ulvaceas ; Prasiolaceae : Cylindrocapsacea? ; ffido- 

 goniacere ; Chsetophoracese ; Aphanochsetaccee ; Coleochcetacese ; Chroole- 

 pidacea-. 



d. Siphonocladiales. 



Families : Cladophoraceae ; Siphonocladiacese ; Valoniaceaj ; Dasycladiacea? ; 

 Sphaeropleacese. 



c. Siphonales. 



Families ; Codiacea 1 ; Bryopsidaceaa ; Derbesiacea 3 ; CaulerpaceM ; Vaucheri- 



IV. CHODAT has recently ('09) proposed a 'natural system' of classification for the 

 Green Alga;, but in many respects the proposed system is very confusing. It is briefly as 

 follows : 



A. Meiotrichales. 



Series I. Protococcales. 



Families : Volvocacerc ; Palmellaeere ; Protococcaceaa (Prot. Zoosporees ; 



Prot. autosporees ; Prot. hemizoosporees). 

 Series II. Pleurococcales. 



Families: Ulotrichace* ; Ulvaceaa ; Pleurococcaceaj ; Prasiolacea 1 ; (.'lia'to- 

 phoracese ; Coleocha>tacere. 



