191S] Gardner: Xc\r Pacific Coast Marine Algae III "ill 



resemble very eloseh' those of a simple Calothrix or a Rivularia. The 

 nature of the branching of Brachytrichia does not seem to have been 

 thoroughly explained previously, or perhaps not sufficiently weighed 

 when its phylogenetic position was first determined. In the group 

 M'ith non-tapering, cylindrical trichomes the family Stigonemaceae 

 was created to receive those heterocysted species which have true 

 branching, while in the group with tapering trichomes the family 

 RiAiilariaceae was created for those heterocysted forms with false 

 branching. The character of true branching, that is, branches con- 

 nately joined, is thus to be weighed as against tapering trichomes in 

 determining the phylogenetic position of Brachytrichia. In our 

 opinion the former outweighs the latter and it is here proposed to 

 remove it from among the Rivulariaceae and place it among the 

 Stigonemaceae where its relationship seems to be closest to Ma.sti- 

 gocolcus. 



In conclusion, it gives me pleasure to acknowledge the many help- 

 ful suggestions of Professor W. A. Setchell in the preparation of this 

 paper. He concurs with me in proposing the new species and has 

 furnished their Latin diagnoses. 



