244 KJELLMAN, THE ALG^ OF THE ARCTIC SEA. 



one, while this has never been observed in the Tangle» {— L. stenopliylla). I think no 

 one is entitled to doubt that this statement of Cluston is founded on coinplete re- 

 seai-ches continued througii the whole ycar. Nevertheless it proceeds from J. E. Aee- 

 schoug's investigations — according to oral Communications kindly given — that the 

 Scandinavian L. digitata changes its lamina periodically in the same mannar as L. 

 Clustoni and that at the fall of the lamina the limit between the young and the old 

 one is quite as distinctly marked as in the last-named species. The same observation 

 has been made by Foslie and set forth in his work Digit. Lam. p. 6. He mentions 

 also that there are quite as distinct yearly rings to be seen in L. digitata as in L. 

 Clustoni, which confirms my observations in respect to L. digitata f. complanata. Cp. 

 Kjellm. Kariska hafvets Algv. tab. 1, fig. 14. Such rings, according to Le Jolis, are 

 not to be found in L. flexicaulis, which I have taken to be identical with L. digitata 

 var. stenophylla Harv. — For these reasons I am opinion that, even after L. Clustoni 

 has been segregated from L. digitata, there still remains in the last-named old collective 

 species not one but two species, the one perennial, annually throwing off its lamina 

 regularly as L. Clustoni and possessing in its stipe thickening-layers of the same kind 

 as in this species, and the other possibly bieunial, as Le Jolis supposes, fast increasing 

 in size, with a stipe that »ne présente pas d'anneaux concentriques» and a lamina that 

 »se développe d'une maniére continue et indéfinie; et pour ce motif peut atteindre de 

 grandes dimensions». The former species is L. digitata of J. G. Agardh and J. E. 

 Areschoug, the latter is L. digitata Edm., L. digitata var. stenophylla Harv., L. steno- 

 pliylla J. G. Ag. It possibly is the former of these species, L. digitata J. G. Ag., 

 Aresch., that Le Jolis refers to 1. c. p. 553, when he says: »Cependant on trouve 

 quelquefois dans le Lam. flexicaulis un état de vegetation qui le rapproche du Lam. 

 Clustoni. Alors un certain arrét a lieu dans la croissance de la plante et un léger 

 rétrécissement s'est manifesté dans uiie partie de la fronde .... c'est dans ce cas encore 

 qu'on remarque dans le stipe du Lam. flexicaulis de traces d'anneaux colores . . .» In 

 such a case L. flexicaulis Le Jol. would include not only L. stenophylla J. G. Ag., but 

 also L. digitata J. G, Ag., Aresch. 



It is another question whether this L. stenophylla is really to be found within the 

 Polar Sea. I have never myself seen any specimen taken hare. My recording it among 

 the arctic algse is founded only on Kleens statement that he has collected it at Nord- 

 landen. I had so much the less reason to doubt its occurrenca here, because the species 

 is apparently northern and moreover is stated by J. G. Agardh to have been collected 

 by himself at Throndhjem. Neverthless I am not quite sura whether Kleen has not 

 mistaken also young individuals of L. digitata with cuneate base growing in rock-pools 

 for L. digitata var. stenophylla. I have myself mat with specimens at Nordlanden which 

 resemble Harvey's figure of L. stenophylla in the form of the lamina, but are un- 

 doubtedly young specimens of L. digitata, 



Habitat. It is said by Kleen to live at low-water mark as well as in rock-pools 

 within the litoral zone. 



Geogr. Distrib. Reported from the Norwegian Polar Sea. 



Locality: Nordlanden: common and abundant according to Kleen. 



