42 



С. Chlopophyeeæ. 



Fam. Phyllosiphonaeeœ. 



Ostreobium Born, et Flah. 



81. 0. Queketti Born, et Flah., K. Rosenv. Deux. Mém. 

 p. 101. 



Earn. Gomontiaceœ. 



Gromontia Born, et Flah. 



82. G. polyrrhiza (Lagerh.) Born, et Flah., K. Rosenv. Deux. 

 !Mém. p. 101. 



Eam. Cladophoraceœ. 



Acrosiphonia (J. Ag.). 



The genus Acrosiphonia is here defined as proposed by 

 Willed and includes only species with many nuclei in each 

 cell. Thus defined the genus is identical with the subgenus 

 Melanarthrum (Kjellman, Acrosiphonia p. 50). It has already 

 been pointed out (Borgesen, Faer. Alg. p. 506, Jonsson Icel. Alg. 

 p. 367), that Kjellman's division of the sub gen. Èlelanarthrum 

 into sections is untenable, at all events it may be regarded as 

 fully demonstrated that the section I, Speirogotiicce, and sec- 

 lion II, Zoniogonicœ, are to be considered as one. In the 

 Greenlandic species of this genus the sporangia certainly mostly 

 occur singly or two or three together, but 5 — 7 sporangia in 

 a continuous row are not rare. Thus the Greenlandic material 

 seems further to show that the above named sections are to 

 be considered as one. Species with spinous branches did not 

 occur in the Greenlandic collections. 



The Greenlandic species are easily distinguishable by the 

 following key: 



>) Botaniska Notiser 1899, p. 281. 



