KONGL. SV. VET, AKADEMIENS HANDLINGAll. BAND. 20. N:0 5. 203 



Adnot 1. F. evanescentis f. angustae proxitne accedit Pucus raiclonensis J. G. As. Spetsb. Alg. Till. p. 35, 



39 et Gronl. Lam. et Fuc. p. 28, saltern quoad specimina Spetsbergensia et Groenlandica. 

 Adnot. 2. In grege formarum inter f. bursigeram et f. typicam intermediarum J. G. Agahdhii Fucus evanescens, 

 minor receptaculis inflatis ad F. bursigerum tendens, me judice est adnumerandus. 

 Syn. Fucus ceranoides Pall. Eeise 3, p. 34. 



» » Post, et Eupk. 111. Alg. p. II; Cfr. Gobi, Algenfl. Weiss. Meer. p. 55. 



» » ScHRENK, Ural Keise p. 546. 



» evanescens J. G. Ag. Spetsb. Alg. Till. p. 27, 35, 40; Gronl. Alg. p. 110; Cfr. supra. 



» » Gobi 1. c. 



» » Kjellm. Vinteralgv. p. 64; Spetsb. Thall. 2, p. 3; Algenv. Murm. Meer. p. 26; 



Kariska hafvets Algv. p. 23. 



» » Quercus Pall. Eeise 3, p. 34. Cfr. sub Delesseria sinuosa. 



» vesiculosus J. G. Ao. Spetsb. Alg. Progr. p. 2; Bidr. p. 11. 



» » AsHM. A.lg. Hayes, p. 96 (?) Cfr p. 199 sub. F. vesiculoso. 



» » Croall, F1. Disc. p. 457; ex parte. 



» » Dickie, Alg. Sutherl. 1, p. 140; ex parte (?); Alg. Cumberl. p. 236; ex parte. 



» » Baton, List. p. 44. 



» » Lindbl. Bot. Not. p. 157. 



» » Martin, Met. Observ. p. 313. 



» » Post, et Eupr. 111. Alg. p. II; saltern ex parte. 



» » ScHiJBELER, in Heuglin Eeise p. 317. 



» » ScoRESBY, Account 1, p. 132. 



» » SoMMEEF. Spitsb. Fl. 233. 



» » Zeller, Zweite d. Polarf. p. 85. 



» » Cfr. Martens Voyage Spitsb. p. 77, t. F, fig. b. 



Remark on the determination of the forms. Fucus evanescens has of late become ever 

 better known, and the algologists who have had an opportunity of studying it have 

 adopted J. G. Agardh's opinion that it is to be considered an independent species. It 

 was formerly confounded with F. vesiculosus, although it is probably less closely allied 

 to this species than to F. edentatus. It differs from the former species by its branching, 

 the shape of its segments, its colour and consistency, and above all by the different 

 structure of its scaphidia. Of F. edentatus I have, on the contrary, seen forn}s very 

 nearly approaching F. evanescens, and, on the other side, forms of F. evanescens much 

 resembling F. edentatus in the shape and size of the receptacles. Nevertheless I believe 

 the two species can be distinguished by certain differences in the ramification of the 

 frond, in consistency and in the nature of the costa. I have set down here the same 

 forms that I have before endeavoured to distinguish and to define. They are certainly 

 connected by numerous intermediate forms, but they deserve however to be mentioned 

 specially, because they show the limits and directions of the variations of the species 

 and differ somewhat with regard to biology and geographical distribution. I have 

 arranged under them the forms mentioned by J. G. Agaedh in his works on the ma- 

 rine Flora of the Arctic Sea. I cannot possibly distinguish Fucus miclonensis J. G. Ag. 

 from Spitzbergen and Greenland, of which I have seen specimens determined by J. G. 

 Agaedh, from low-sized F. evanescens f. angusta and from intermediate forms between 

 this and f. nana. Faklow says of f. miclonensis De la Pyl. »F. miclonensis of De la 



