KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 173 



Ptilota plumosa (L.) Ag. 



Sijn. Alg. p. 39, excl. (j. Fucus plumosus L. Mänt. p. 134. 

 Descr. Ptilota plumosa .T G. Ag. Epicr. p. 75. 

 Fig. » » Haiiv. Phyc. Brit. t. 80. 



ExsioG. > >> Arescii. Alg. Scaiid. exsioo. N:o 160. 



Syn. Fucus plumosus R. Bk. iu Scoresby, Acoouut., 1, p. 132 et append V? Noiuie Pt. pectinata? 

 B » GöNN. Fl. Norv. 2, p. 91. 



» » a et (i Wg. Fl. Lapp. p. 501. 



« ptilotus GuNN. Fl. Norv. 2, |). 135. 

 Plumaria pectinata var. tenerriraa Rupil. Alg. Och. p. 336. 

 Ptilota plumosa J. G. Ag. Spetsb. Alg. Progr. p. 3; Bidr. p. 11. 

 » » Aresch. Phyc. Scand. p. 319. 



» » a typioa GoBi, Algenfl. Weiss. Meer. p. 44. 



a « Harv. Ner. Am. 2, p. 224. 



)) ■ » Kjellm. Spetsb. Tliall. 1, p. 26; Algenv. Murm. Meer. p. 22. 



» . » Kleen, Nordl. Alg. p. 20. 



» » Lyngb. Hydr. Dan. p. 38. 



» n var. tenuissima Sciiijbeleii in Heugl. Eeise, p. 317. 



» » WiTTR. in lieugl. Reise, p. 284. 



Habitat. This species is generally sublitoral, occurring in 5 — 20 fathoins water 

 on stony or pebbly bottom. Sometimes it is found in inore sliallow water, even within 

 the litoral zone in rock-pools between tides. It is attached sometimes to other algai, 

 usually to stones, and grows on exposed coasts as well as in the interiör of bays and 

 at other sheltered places. I never found it gregarious. On the coasts of Spitzbergen 

 and Novaya Zemlya it usually constitutes an element of the Laminariaca3-formation; on 

 the west coast of Norway I have generally found it in company with purely arctic 

 algas. Here it attains a high degree of luxuriancy. The largest specimens I ever 

 saw, from the interiör of Altenfjord, had a length of 20 — 25 cm. The plant has not 

 been examined in winter in the Polar Sea. Individuals with sporocarps have been 

 found at Nordlanden in July and August, at Finmarken at the end of August and in 

 the earlier part of September, at Spitzbergen in July, ou the west coast of Novaya 

 Zemlya and Waygats in August and at the end of June. Specimens with tetrasporangia 

 have been collected in most of these parts of the Arctic Sea in July and August. 



Geogr. Distrih. The present species belongs both to the Atlantic and the arctic 

 region of the Polar Sea, having its maximum of frequency within the former. Its most 

 northerly known locality is the outer Norse Island off the north-western coast of Spitz- 

 bergen Lat. N. 79° 50'. 



Localities: The Norwegian Polar Sea: Nordlanden, common and plentiful; Fin- 

 marken: Maasö, Gjesva3r, Magerö Sound, Öxfjord, and Talvik, abundant, but local. 



The Greenland Sea: According to my experience, local and scanty on the coasts 

 of Spitzbergen. 



The Murman Sea: the coast of Cisuralian Samoyede-land; the west coast of No- 

 vaya Zemlya and Waygats from Matotshin Snar to Jugor Shar, pretty common and 

 abundant. 



