KONGL. SV. VET. ARADEMIENS HANDLINGAR. BAND. 20. N:0 5. 205 



f. typica nob. 

 Descr. Fucus furcatus Akesch. Puc. et Pyciiopli. p. 107. 

 Exsico. » » Kjellm. in A.resch. Alg. Scaiid. exsicc. N:o 401. 



f. contracta nob. 



f. pai-vula, thallo circa 10 cm. alto, coriaceo, dense dichotomo; segmentis inferioribus ad costas validas, 

 firraas reductis, saperioribus alatis, costa distincta vel subdistincta, 3 — 4 mm. latis; receptaculis cylindrico-fusi- 

 formibus, simplicibus vel rarius furcatis 1,5 — 2 cm. longis, diametro 3 mm.; scaphidiis creberrimis, minutis. 



Syn. Fucus furcatus Aeesch. Fuc. et Pycnoph. p. 107, quoad spec. Norvegica et Groenlandica. 



Remark on this species. J. G. Agaedh in Spec. Alg. identifies Fucus furcatus Ag. 

 with Fucus edentatus De la Pyl. To this view J. E. Aresghoug accedes on account 

 of a specimen communicated by Harvey; Fuc. et Pycnoph. p. 109. It is however 

 contested by Ruprecht who shows F. furcatus Ag. and the alga described by Agardh 

 under this name to be two rather distant forms which differ even so much that thev 

 ought to be referred to different species; Alg. Och. p. 346. From this cause J. G. 

 Agardh in his survey of the species of Fucus abandons his former view and sets down 

 Fucus edentatus De la Pyl. as specifically distinct from F. furcatus Ag. Spetsb. 

 Alg. Till. The identity of the Fucus in question, occurring on the north coast of 

 Norway, with Fucus edentatus De la Pyl. appears to me to be beyond a doubt. As I 

 have not, among the great number of specimens from Norway and the north-eastern 

 coast of North America examined by me, found any that agrees fully with Agardh's 

 figure of F. furcatus, I have thought best to follow J. G. Agardh's later exposition, 

 regarding F. edentatus as specifically distinct from F. furcatus Ag. 



As respects the form that I have described above under the name of f. contracta, 

 it is incontestably united by intermediate forms with the typical form, that is to say, 

 that delivered by me for distribution in Areschoug's Alg. Scand. exsicc. Being however 

 pretty unlike this and at the same time resembling in many respects other species of 

 Fucus: F. Fueci, F. miclonensis J. G. Ag. and F. distichus, I have thought fit to point 

 it out specially, lest it should be described as a separate species by some one who has 

 not had an opportunity of seeing the transitions between it and F. edentatus f. typica, 

 or lead to some sort of unnatural combination of Fucus edentatus with some of the 

 species mentioned above. 



Besides these forms, f. typica and f. contracta, there is to be found on the north 

 coast of Norway even a third form which is perhaps worthy of attention, being ana- 

 logous to f. grandifrons of F. serratus, f. vadorum of F. vesicolosus and f. pergrandis of 

 F. evanescens. However, all the specimens on which this opinion is founded being sterile, 

 I cannot here enter into details, but only wish to draw the attention of future investi- 

 gators to the subject. 



Habitat. The species is exclusively litoral, and lives within the lower part of 

 this zone, occupying a region situate between Fucus serratus on the one side and F. 

 vesiculosus and F. spiralis on the other, as has been pointed out already by Kleen. It 

 seems to prefer exposed localities and is found gregarious in large numbers on exten- 

 sive areas of the bottom on the coast of Norwegian Finmarken. Farther southwards 



