Phytogeny 29 



Bumilleria, Botrydiopsis, Chlorobotrys ; (2) Chlorotheciacece, which 

 includes Mischococcus, Peroniella, Stipitococcus, Characiopsis, 

 Ghlorothecium ; (3) Botrydiacese, including Botrydiiun. Now, 

 amongst the Flagellate organisms there exists a genus described as 

 Vacuolaria by Cienkowski 1 , which possesses yellow -green discoidal 

 chromatophores without pyrenoids ; and this organism, as in the 

 case of the Chlamydomonad-type, may very possibly be the start- 

 ing point of the Confervales. Lagerheim discovered another 

 organism in 1897 which was further worked out by Bohlin- and 

 named Chloramceba. It is of a similar type to Vacuolaria with 

 discoidal chromatophores of a yellow-green colour, but more 

 strictly a Flagellate. Great interest is likewise attached to the 

 discovery by Luther 3 in 1898 of yet another similar organism 

 which he named Chlorosaccus. This organism has certain resem- 

 blances to Tetraspora, but is of a yellow-green colour with several 

 parietal disc-like chromatophores, and seems to connect Chlo- 

 ramoeba and Vacuolaria with the direct line of descent of the 

 Confervales. Luther proposed to remove all these forms out of 

 the Chlorophycese and suggested the name ' Heterokontce ' as a 

 class equal with that of the Chlorophycese, and to include the 

 Algal series ' Confervales ' and the corresponding Flagellate group 

 ' Chloromonadina ' (or Chloromonadales). This class seems a very 

 natural one and differs from the Chlorophycese in certain cyto- 

 logical characters, such as the abundant presence of xanthophyll 

 and the presence of a fatty substance as the stored product of 

 carbon-assimilation. 



Bohlin has recently suggested that the Vaucheriacese should 

 be included with the ' Confervales ' and ' Chloromonadales ' as one 

 of the orders of the Heterokontce, with the name ' Vaucheriales.' 

 There are, however, wide differences in structure between the 

 Vaucheriacece and the Confervales, not to mention the absence of 

 the yellow pigment and the highly differentiated sexual repro- 

 duction present in the former ; neither is there any evidence that 

 the plants of these orders are in any way phylogenetically related ; 

 therefore, for the present, I prefer to retain the Vaucheriacese in 

 the order Siphonea- of the Green Algae. 



The origin of the Phseophycese, or Brown Algas, from brown 



1 Cienkowski in Archiv. fiir Mikroscop. Anat. vi, 1867. 

 - Bohlin in'Ofvers. af K. Vet.-Akad. Forh. 1897, no. 9. 

 3 Luther in Biliang till K. Sv. Vet.-Akad. Handl. Bd xxiv, 1898, no. 13. 



