84 KJELLMAN, THE ALGiE OF THE ARCTIC SEA. 



cially for the purpose of assimilation. These facts caii and certainly ought to be 

 explained in the following way. In its original home, tlie Arctic Sea, this plant has 

 need of tlie whole year, and, during that time, of all its assimilating organs in order 

 to accoinplish its development; whereas on the coast of Bohuslän, where it has come 

 into inore favourable conditions, it is able, by carrying on assimilation for only a part 

 of the same time, to form such a quantity of nutrient substances as suffices not only 

 to develop the reproductive organs, but also to supply the assimilating organs, that 

 it has cast off after they have functioned during the necessary time. 



With regard to the physiology of nutrition, the arctic algaj are in several respects 

 most instructive. They may during very long periods be inclosed in ice and exposed 

 to high degrees of cold, without being killed or losing their power to resumé vigorously 

 their development, when the hindering fetters have been broken. Still more, they 

 prove that plants can germinate at a temperature of from — 1° to — 2° C, and are 

 able, without being checked in their vital functions by the temperature scarcely ever 

 rising to the freezing-point, to develop into magnificent forms producing endless masses 

 of reproductive cells throughout all the year or during the greater part of it. We 

 have thus in these algas vegetative organisms whose optimum of temperature may be 

 stated to be about or beloAv zero C. Besides, the energy of assimilation requisite for 

 this rich and vigorous development seems to comport vei'y ill with the slight quantity 

 of light afforded to these plants. As far as I can judge, this cannot be explained 

 otherwise than by the assuraption that the arctic alga3 in general are content with a 

 very inconsiderable measure both of light and of warmth. 



With the modern theories on the nature of the process of assimilation, it is cer- 

 tainly difUcult to assume that the algte should continue uninterruptedly their assimi- 

 lation at the 80:th degree of latitude during the winter when there prevails an almost 

 absolute darkness to the human eye; but such an assumption becomes almost necessary 

 on account of the rich and vigorous development of new parts that was proved to take 

 place during the winter. Otherwise one would be obliged to assume that the consi- 

 derable quantity of plastic substance used up by the alga3 in forming new organs 

 on a large scale during the dark season, are nutriments stored up in reservs du- 

 ring the preceding period of light. I cannot affirm decisively that this was not the 

 case. But on the materials that I have had at my disposition, such an assertion cannot 

 be founded. Certainly, several Florideaä contained a remarkably large quantity of solid 

 substances in their cells during the winter. But neither in the Fucoidege nor in the 

 Chloropliylloijhycece such stores were to be detected. However, nutrient substances in 

 reserve may have occurred in them in a liquid form. I had no means of investigating 

 this '). If the raw materials are assumed to have been gathered during the light season, 

 this implies, on the other hand, that nutritive substances must be prepared then to an 

 extraordinary extent, as not only all the material is to be formed of which vegetative 

 organs are built, but also a sufficient quantity is to be reserved for the developing of 



^) It ought to be remarked here that the observations to which I refer chiefly, were carried on during an iu- 

 voluntary and uupremeditated wintering on the north coast of Spitzbergen. 



