KONGL. SV. VET. AKADEMIENS HANDLINGAIi. BAND. 20. N:0 5. 81 



surely not annual. This seems especially improbable in respect of such algfe as Rlio- 

 dochorton Rothii, RJiizoclonium riparium, and Fucus evanescens. For on the coast of 

 Novaya Zemlya I have seen all these algte fully developed early in the year, before 

 the land-ice broke up or just as it was dispersing. Thus I cannot but assume that 

 they had lain frozen and covered with ice during winter, and when delivered at last from 

 their cold cover resumed at once their development which had been interrupted by the ice. 

 I have in the arctic region seen quite evident instances of algse being frozen and in- 

 closed in ice and continiiing their development when delivei"ed. In a lagoon at Pitlekay, 

 which during the winter froze to the bottom, there was found in abundance an Entero- 

 morpha which I have below named E. micrococca f. suhsalsa. When the ice of the 

 lagoon melted at the end of June, this plant reraained at the bottom in large seemingly 

 lifeless masses. But in a short tirae it began to develop vigorously by producing new 

 shoots from the parts which had persisted through the winter. This being so, it is 

 quite possible that all the species which are litoral within the arctic region, persist all 

 the year round and do not complete their development in one year, but in two or 

 three years, with longer or shorter interruptions. Accordingly there is as yet no sure 

 evidence of the existence of annual species among the arctic algae. I believe, however, 

 that such species are to be found on the west coast of Greenland, and that, besides, 

 the first-mentioned Chlorophyllophyceaä are probably also annual. But in any case, to 

 State it broadly, we may say with regard to the arctic region, that the conditions 

 under which the algaj live there, are such that annual algte cannot endure or at least 

 cannot occur in any larger number either of species or of individuals, and that the 

 perennial species, in the very most cases, need the Avhole year to reach the develop- 

 ment designed for each period of growth. 



But though the development of the arctic algaä is thus extended throughout the 

 whole vear, there appears a certain periodicity at least in certain species. For it may 

 be regarded as a pretty general fact that the purely vegetative development is livelier 

 and more energetic during the favourable season, while the development of propagative 

 organs, on the contrary, is stronger and richer in the latter part of the auturan, in 

 winter, and in early spring. But nevertheless I cannot but maintain the statement 

 I have made once before, that a development of vegetative parts takes place on a very 

 large scale on the coast af Spitzbergen during mid-winter, when the sun is at its lowest 

 beneath the horizon and consequently the darkness is intense. Spores gerrainated and 

 grew into pretty well developed embryonic plants. Of several species, for instance, 

 Delesseria sinuosa, young plants were common towards the end of the dark season. It 

 could not well be doubted that these had been developed during the winter-months. 

 Older plants of the same species, and also of Halosaccion ramentaceuin, Rhodymenia 

 palmata, Phyllophora interrupta, Rhodomeln lycopodioidet^, Sphacelaria nrctica, Phloeospora 

 tortilis put forth new shoots in winter, which were in course of growth and more or 

 less developed at the entrance of the light season. However, it must be admitted that 

 the development of such organs did not set in with greater vigour nor produce any 

 considerable results before the beginning of Maj?. 



K. Vet. Akad. Handl. Band. 2(1. N:o ö. 1 1 



