Classification 149 



E. Microsporales. 

 Family : Mierosporaceae. 



F. Stephanokontae. 

 Family : (Edogoniacese. 



Shortly afterwards, Blackman & Tansley ('02) pursued somewhat 

 further the lines suggested by Bohlin and Luther, separating not only 

 Luther's ' Heterokontse,' but also the (Edogoniales as Bohlin's ' Stephano- 

 kontae,' and the Conjugates as the 'Akontae,' from the remainder of the 

 Chlorophyceae, which were placed under the ' Isokontse.' They also accepted 

 Bohlin's suggestion that all these four groups were phylogenetically inde- 

 pendent and that each group had most probably had a direct Flagellate 

 ancestry. 



The bold effort of the above-mentioned authors to establish a reliable 

 basis for the classification of the Green Algae was in every way admirable 

 in its broad outlines. Many matters of detail have required readjustment, 

 and certain theoretical questions have had to be considerably discounted; 

 but notwithstanding its defects, this combined effort, due in the first instance 

 to the inspirations of Swedish algologists, will always remain as the one 

 which paved the way for the establishment of a sound classification of the 

 Chlorophycese. 



The following is a brief synopsis of the recent proposals concerning the classification of 

 Green Algse, with critical remarks thereon. It will be found useful for purposes of 

 reference only, as a strict comparison of the various propositions is not possible from such 

 a synopsis, owing to the frequent use of the same group-names in widely different senses. 



I. BLACKMAN & TANSLEY ('02) advocated the separation of the three groups of the 

 Heterokontse, Stephanokontae, and Akontae from the remainder of the Chlorophyceae, which 

 were placed in the Isokontae. With these four primary divisions the present author is in 

 entire agreement, provided they are regarded as groups of Green Algae of equal standing. 

 The ancestry of the Heterokontae and Isokontae is in some respects fairly clear, but that of 

 the Akontae and Stephanokontae is most obscure. The separation of the Stephanokontae is 

 based upon the great constancy of the characters of the zoogonidia in the Isokontan and 

 Heterokontan series, and the absence of intermediate forms between any of these 

 types of zoogonidia and the multiciliated zoogonidium of the Stephanokontae. In this 

 classification the authors followed Bohlin in placing the Vaucheriaceae in the Heterokontae, 

 and Palla in the arrangement of the Conjugatae. They did not, however, accept Bohlin's 

 disposition of the Microsporales as a group parallel with the Ulotrichales, Briefly, the 

 arrangement was as follows : 



Class I. Isokontae. 



Series 1. Protococcales. 

 Group 1. Volvocinese. 



Families : Polyblepharidese ; Chlarnydomonadaceae ; Polytomaceae ; Pha- 

 cotaceae ; Volvocacese. 



