390 



Tetrasporic specimens were found in June; piants from October to 



December consisted usually of the basal disc only, though sometimes 



they bad a very few erect branches. 



It has bcen found in the following localities: — Vid.: Kvannesund 

 (H. J.) ; Bord 6: Haraldsund (H. J.); Str.: Kalbakfjord (!), Gliversnæs (!); 

 Syd.: Trangisvaag (H. J.). 



63. Rh. Rothii (Turt.) Nagl. Kjellm., N. I., p. 232 (185); Rosenv., 

 Grønl. Havalg. p. 791 ; Callitbamnion Rotbii Lyngb., Hydropbyt. 

 p. 129. 



f. typica. 



f. globosa Kjellm. 



Tbis plant, which is very common along the Færoese coasts, 

 varies considerably according to its different habitats. It occurs 

 as a short, perfectly dense, and evenly spreading crimson covering 

 on rocks and stones between tide- marks: most frequently in 

 narrow rock-clefts; on the walls in the interior of caves; and in 

 openings between tumbled down blocks of rock »Ur«; f. typica is 

 most common in such localities. Formå globosa is met with on 

 vertical rock-faces in much exposed localities from bigh-water mark 

 to several feet above it; it is especially common on vertical rock- 

 faces in caves, and on rocks with a northern aspect, where it oc- 

 curs in small, semiglobular, very solid bodies, about the size of a 

 pea, often growing more or less together and forming small irre- 

 gular crusts. Judging from the following description of Lyngbye 

 (1. c.) he has undoubtedly observed tbis form: — »Caespites minu- 

 tissimi, 2 — 3 lineas alti, maxime gregariæ, interdum ad latera rupium 

 glomerulos durissimos formantes«. The lower part of the filaments 

 were 17 \i thick, higher up they become thinner, about 11 \i. The 

 cell-walls were often very thick, some I measured were as much 

 as 3 i« thick. When Kjell man says that the lower articulations of 

 f. globosa are almost as long as broad tbis does not correspond 

 with the Færoese specimens, the articulations of the latter being, 

 also at the base, twice or tbrice as long as broad. 



Formå typica varies considerably in thickness; generally il is 

 about 10 fi thick, but I have often come across filaments measuring 

 15 to 20 fi; in a single small example the filaments bad even at- 

 tained to a thickness of 29 p. It also appears to be a rule thai 

 the higher the plant grows above sea-level, or in otber words, the 

 more frequently and especially the longer il is left dry, the thicker 

 the branches grow, as also the cell-walls. Rosen vinge (l.c.) reports 



