ICONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 149 



Remark on the deter mination and the synonymy of this species. Iii the above attempt 

 to group the arctic forms of this many-shapecl species the forms constitute two series. 

 The former of these, coinprising f. typica and sarniensis, is characterized by the ma- 

 jority of the secondary axes of the frond being formed by repeatedly subdichotomous 

 branching, the latter, comprehending f. prolifera and f. angustifolia, by all, or most, 

 secondary axes being so-called prolitications. The specimens of the typical form, 

 most common in the arctic parts of the Polar Sea, are very magnificent, large, and 

 high-coloured. They are undoubtedly the largest Floridece of this region. The typical 

 form occurs more rarely in the habit represented by pl. 217 in Harv. Phyc. Brit. and 

 named by Harvey f. maiyinifera. It is easily seen, however, that the diagnosis, borrowed 

 from Stackh. Ner. Brit. (p. 54), which accompanies the figure in Hakvey does not 

 accord with the plant delineated The forms sarniensis and prolifera. are sometimes 

 rather difficult to distingnish from each other. The form distributed by Areschoug in 

 his work of Scandinavian exsiccates under the name of f. sobolifera approaches more 

 nearly to f. sarniensis, especially to A' tenuissima. I have assumed that Kutzing by his 

 Sphcerococciis palmatus y prolifer means the arctic broad-fronded, high-coloured form 

 (« piurpurea nob.). But I am not certain of it. This form is nearly related to what I 

 have called f. prolifera P pallida, which is common in Kattegat and Skagerack and is 

 possibly to be found also in the southern part of the Norwegian Polar Sea. However, 

 [i pallida ditfers so much in colour as to deserve special mention. Another form, very 

 beautiful, which connects the two series with each other, but accords most closely with 

 f. prolifera, is f. angustifolia, a proliiicating form with narrow frond, that attains some- 

 times half a foot in length and becomes much branched by repeated prolifications. 

 Sometimes it is very little, 1 — 2 inches long, with very small prolifications. It is pro- 

 bably a stunted form either of f. angustifolia or of f. prolifera that J. G. Agardh has 

 named f. micropliylla in his list of the algaa brought home from Spitzbergen by the 

 Swedish expedition of 1868 and distributed by him. 



Hahitat. In the Greenland Sea and the eastern part of the Murman Sea as well 

 as on the west coast of Svveden the present species is sublitoral, in the Norwegian 

 Polar Sea it is litoral. I do not know how it is in the other parts of the Arctic Sea. 

 In the first-mentioned seas it grows on stony bottom at a depth varying between 3, 

 seldom less, and 15 fathoms, sometimes gregarious, sometimes scattered together with 

 Fucoidece. On the coast of Norway it keeps chiefly to the lower part of the zone of 

 the Fucacece, usually covering stones and rocks in large, dense masses together with 

 Fucacece. At more free places where it is less covered and oppressed by other algaä, 

 it appears liere in its typical form or as a large-sized f. prolifera cc pjurpturea. When 

 growing, on the contrary, among dense masses of FucacecB, by which it is covered at 

 low-tide, it assumes the habit charakteristic of f. sarniensis, angustifolia, or dwarfed 

 prolifera. It occurs chiefly on exposed coasts, but enters also into deep bays, even 

 where the water is comparatively little salt during some parts of the day. Cp. 

 Kleen, Nordl. Alg. p. 17. On the north coast of Spitzbergen the present plant is 

 developing all the year round, even in wiuter. During the whole time from the 

 beginning of November to May, accordingly during the whole dark and cold season, I 



