KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 20. N:0 5. 137 



Syn. Fucus Querous Pall. Sib. Reise 3, p. 34. (?) 

 » rubens Gunn. F1. Norv. 2, p. 69. 

 » sinuatus R. Br. in Scouesby, Account 1, App. 5. 

 » siiuosus ScoREsBY, Account 2, p. 131. 

 ' 1) y. Wg. Fl. Lapp. p. 491. 



Pliycodrys sinuosa Zeller, Zweite d. Polarf. 2, p. 86. 



Remark on the arctic forms of this species. Delesseria sinuosa is one of the com- 

 monest algge of the Polar Sea and occurs in a great many varieties. These may how- 

 ever, I think, be arranged under the three above-mentioned forms, which were di- 

 stinguished long ago. For I have convinced myself that the form I have formerly 

 called f. angusta, is to be referred to f. lingulata Ag. The most common of the forms 

 is the D. sinuosa of the older authors. In certain parts of the Polar Sea it attains a 

 considerable size and is surely to be reckoned among the most magnificent algae of 

 this sea. I have seen specimens more than 30 cm. long, with leaf- shaped branches of 

 even 18 cm. in length, by 3 — 4 cm. in breadth. Another form which approaches most 

 nearly, although it never quite coincides with, the f. quercifolia common in Skagerack, 

 is less often to be observed. F. lingulata is more common, differing, when most sharply 

 marked, most considerably from the other forms, with which it is however connected 

 by intermediate conditions. Such a transition to f. typica, extremely pretty and charac- 

 teristic, is the variety recorded by Kleen from Nordlanden. Other intermediate forms, 

 that I have taken at other places in the Arctic Sea, resemble so closely the figure 

 KuTZiNG gives of D. Lyallii in Tab. Phyc. 16, t. 14, that they cannot be distinguished 

 in habit from this species. I have pretty often found individuals of f. lingulata with 

 some, or most, or all branches of the last order or the last order but one filiform, 

 upwards of 3 — 4 cm. long. These branches are sometimes terete in their whole length, 

 sometimes flattened at the tip. Some specimens found at Spitzbergen lying loose on 

 loamy bottom are especially remarkable in this respect. Harvey mentions such spe- 

 cimens from the coasts of Great Britain, cp. 1. c. Even the typical form has some- 

 times such branches of the last order, but these are shorter. 



Habitat. This plant everywhere in the Polar Sea is sublitoral or elitoral. It occurs 

 usually in 10 — 20 fathoms, sometimes in more shallow water, l\ — 2 fathoms deep, or 

 at very great depths. It has been dredged at Spitzbergen quite fresh in 85 fathoms. 

 When growing in shallower water, it belongs to the formation of Laminar iaceas, in 

 deeper places it is luostly fojind in company with Odonthalia dentata, Polysiphonia arc- 

 tica, Phyllophora interrupta, Ptilota pectinata and some others. It prefers exposed coasts 

 and a bottom of solid rock, but is also met with in the interior of deep bays and on 

 bottom formed of pebbles, shells and Lithothamriia. 



During the earlier part of the winter only older specimens were to be found on 

 the north coast of Spitzbergen, but from the beginning of January young individuals 

 became common. Although in the older ones the looser parts of the frond were more 

 or less injured and destroyed, probably by animals, they were however in course of 

 developing new parts, that were easily distinguished by their greater slenderness and their 

 lighter and clearer colour. Older specimens bore tetrasporangia throughout the winter, 



K. Vet. Akad. HaDdl. B, 20. N:o ,5. 1 " 



