KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 209 



doubtful to which of them a given form is rightly to be referred. But from this 

 fact that certain forms of Fijcus resemble one another, it does not in my opinion 

 follow necessarily that they afe phylogenetically allied. For although dwarfed forms 

 of for inst. F. vesiculosus, F. evanescens, and F. ceranoides happen sometimes to be so 

 like as to make it hardly possible to establish any limits between them, yet these forms 

 may be traced by intermediate ones into such forms as F. vesiculosus f. vadorum, F. 

 evanescens f. pergrandis, and F. ceranoides f. typica, which will certainly not be regarded 

 by any one as forms of one and the same species. I believe that the above-mentioned 

 species of Fucus hitherto only little attended to, either are links of different series of 

 forms or of the same series — perhaps one culminating in F. edentatus f. typica — or 

 else are really different species. This point has not as yet been cleared up, and before 

 this is done, it would be inconsiderate to unite the species in question into one. In 

 such a case much more would have to be added to this collective species, and consi- 

 stently all the northern Fuci must be thrown together into a chaotic whole — a mode 

 af proceding which is certainly very convenient with regard to the systematization of 

 a group rich in forms, but can hardly be considered satisfactory. 



Although I acknowledge sincerely that the plant, which I have called F.JUiformis 

 and which according to the kind communication of J. G. Agardh is identical with the 

 alga thus named by him, is difficult to define sharply from other species, I do not 

 think, however, that I am justified either by the experience acquired by examining a 

 great number of living and preserved individuals or by reasons adduced by others to 

 refer it as a subform to any other species. Accordingly, I retain it at present as a 

 separate species. 



Habitat. This alga in company with F. distichus forms sometimes the principal 

 vegetation in rock-pools within the upper part of the litoral zone. I have met with 

 it both in exposed and sheltered localities. Its proper season of fructification on the 

 north coast of Norway seems to be in June and July. It was found sterile in August 

 and October on the coast of Finmarken. 



Geogr. Distrib. Known from the southern part of the Polar Sea north of the 

 Atlantic. Its maximum of frequency is on the coast of Norway. The northernmost 

 place where it has been found is Maaso, about Lat. N. 71°. 



Localities'. The Norwegian Polar Sea: Nordlanden common; TromsO amt, abundant 

 at several places about the town of Troraso; Finmarken: MaasS, GjesvEer, and the south 

 coast of MagerO, pretty common and plentiful. Besides, it has been brought home 

 from Krog5nas by Bergguen according to J. G. Ag. 



The Murman Sea: the coast of Russian Lapland. 



The White Sea: at the Solowetzki Isles. 



Baffin Bay: the west coast of Greenland at Fridrikshaab and Rittenbenk. 



Of the two forms f. Omelini is in my experience the more covnraon one. 



27 



K. Vet. Akad. Handl. B. 20. N:o 5, 



