Phylogeny 



31 



Flagellate organisms seems quite as reasonable as in the parallel 

 case of the Green Algae. During recent years many genera of 

 primitive brown Algae have been discovered, most of which appear 

 to be intermediate forms between the higher brown Flagellates and 

 the simpler types of filamentous brown Algae. The majority of 

 these primitive brown Algae inhabit fresh water, but few of them 

 have up to the present been observed in Britain. The Flagellate 

 organism suggested as the possible starting point for this series is 

 Chromulina Cienk. 1 , and the ascending series of forms include 

 Phceocystis Lagerh., Phceosphcera West & G. S. West, Phceococcus 

 Borzi, Entodesmis Borzi, Phceothamnion Lagerh. and Pleurocladia 

 A. Br. Divergences along other lines from Chromulina may have 

 given rise to the Hydruraceae, the Chrysomonadinaceae and the 

 Dinobryaceae. Phceodactylon Bohlin and Stichogloea Chodat may 

 have a relationship with the Phceococcus-type of brown Alga. 



PILEOPHYCE.E 



Pleurocladia 



PhsBothamnion 



Entodesmis 

 Phaeococcus 



Phaeosphasra 

 Hydruraceaa Pkseocystis 



Phaeodactylon 

 Stichogloea 



Dinobryaceaa 

 Chrysomonadaceaa 



Chromulina 

 PKOTOMASTIGINA 



The origin of the Bacillarieae is still extremely doubtful, and 

 no reasonable suggestions have yet been put forward as to their 



Cf. Lagerheim in Ofvers. af K. Vet.-Akad. Forh. 1896, no. 4, p. 288. 



