3g4 Andu. Lundagk» 



being exposed al Ihc very coldest period. I had no opportunity to 

 observe the lale with which these (lowers niel. 



When tlie snow lies longer on large ilal stretches of land than 

 on a more rugged ground, it is due both to the Tact that on the 

 plain there is a thicker layer of snow and to the fact that the sun 

 dissolves this more easily on a rise in the ground. 



The thickest covering of snow which I have seen disappear so 

 early in the year that the underlying vegetation could come forth 

 was the 2-melre thick layer of snow between the thermometer-stand 

 and the villa, which, in 1908, melted before the middle of July. But 

 here, this deposit of the layer of snow was owing to the presence 

 of the villa, so that the condition of the vegetation previously existing 

 was changed by chance. The appearance of the vegetation does not 

 enlighten us, therefore, with regard to what the aspect would have 

 been if the place had been hidden every year under such a covering. 



As already mentioned the snow lay somewhat more continuously 

 in 1907 than in 1908. But there are always places where, in accor- 

 dance with the nature of the ground, the snow must be heaped up 

 in drifts, for instance in narrow fissures, and rock-crevices. Here 

 it might be expected, then, that the snow would cover those species 

 which, on account of their delicate nature, had not dared to venture 

 forth in more exposed places ; where, moreover, they would not 

 find such a good substratum as such fissures, with their great possi- 

 bility of humus-formation, might be able to offer. 



When, now and again in the winter, I found such a fissure 

 which, in consequence of its favourable exposure, might be supposed, 

 during summer, to contain species which usually did not occur near 

 that place on the rocky flat, I always visited it in the summer, 

 provided it was possible to do so, and if it was early in the summer 

 I regularly suffered the disappointment of finding it filled with ice, 

 and otherwise, if the ice had managed to melt away, I found it, in 

 most cases, quite barren ; as it naturally must be, seeing that the 

 ice, as a rule, does not have time to melt. 



Many such well-protected localities lose their importance as 

 regards the vegetation just b\' this, that, early in the summer, melted 

 snow from higher lying places oozes into them during the day and 

 saturates a part of the snow, which then, during the cold of the 

 night, is transformed into a solid mass of ice, which thaws very 

 slowly. 



From a biological point of view the essential importance of the 

 snow is that it prevents evaporation in winter and produces mois- 

 ture in summer. When, as is the case, the conditions are such that 

 the country receives almost all its precipitation in the winter, the 



