255 



thinner in the younger. The length of the branches varies also 

 considerably passing with even stages from quite short to long all 

 of which again are sometimes more or less branching, the short 

 branches can therefore Iiardly be called rhizoids (as also pointed out 

 by Rosenvinge) as Kjellman calls these short branches of the main 

 form. True rhizoids do not occur in the specimens from the Færoes. 

 The ramification is besides very irregular, sometimes longer 

 portions of the filaments are quite branchless (hg. 2 a) and sometimes 

 thej' are richly ramified in the characteristic irregular way men- 

 tioned by Kjellman, Gay, Rosenvinge and others (fig. 2 c), most 

 frequently the basal wall of the lateral branch occurs straight in 

 front of the cross- wall in the main filament, but its position as 

 shown in fig. c can vary considerably. 



316. R. sp. Plate X, fig. 3. 



In 1896 I found on damp rocks near Klaksvig a Rhizoclonium 

 which together with sterile Oedogonia and Zygnema, etc. formed a 

 green covering on moss. 



Tilis Rhizoclonium is rather remarkable and doubtless deserves 

 to be regarded as a distinct species. Being ramified it puts one in 

 mind of R. pachijdermiim, but it was not however so richly ramified 

 as the latter species, such ramified parts as shown in fig. 3 a and b 

 occurred only now and then. Branchless filaments were most fre- 

 quent, fig. 3 c and d are smaller portions of such filaments. Here 

 and tliere thick, short rhizoids occurred, always without dissepiment 

 in open connection with the mother-cell. I have not seen multi- 

 cellular rhizoids. The filaments were often geniculated at the 

 rhizoids. The ramification was as usual irregular, as shown in the 

 figures. The thickness of the cells varied with an average of about 

 35 /' and the length of the cells was about IV2 — 3 times longer. 

 The cell-wall was rather thin, in older cells it sometimes attains 

 to a thickness of 5 ft. 



This species can hardly be referred to any of the 5 species 

 mentioned by Stockmayer in his paper: »Ueber die Algengattung 

 Rhizoclonium«'^, only two of them are ramified, R. pachydermum and 

 R. Hookeri, and it is quite distinct from both of them. In »Grøn- 

 lands Havalger« (p. 913) Rosenvinge mentions Rhizoclonium riparum 

 var. polyrhizum Rosenv. which sometimes has unicellular rhizoids 

 without dissepiment, but unicellular rhizoids with dissepiment as 



^ Verhandl. der Zool.-bot. Gesellsch. in Wien 1890, p. 571. 



