X 



gica] nature. It is our hope that biological studies on the spot, which 

 are highly necessary, will be promoted by these papers; just as it 

 is one of the objects of the Danish Arctic Station on Disco to study 

 such biological and physiological problems as require a longer 

 sojourn (summer and winter) at the same place and the help 

 of laboratory instruments. 



Moreover, we hope that these papers will also render possible 

 comparisons with the same species from other and quite different 

 regions, e. g. the Temperate or Alpine regions, and also will serve 

 to demonstrate whether differences do occur or do not; after which 

 the question will arise: What reason is there for these differences? 

 hi the investigations published in the present volume it has been 

 possible to make such comparisons in only a very few cases, one 

 of the reasons being that the material in hand did not allow 

 of such comparisons ; for . usually , the notes regarding the 

 conditions under which the plants were found were not sufficiently 

 exhaustive. 



As regards the points which now require to be investigated 

 in Arctic countries, the reader is referred to "Meddelelser om 

 Grönland," vol. XXX, where the instructions given to the botanist 

 of the Amdrup Expedition, Mr. С Kruuse, have been published. 

 From these we shall here extract some points concerning the 

 Biological questions: — 



1. The condition in which plants liave passed the winter: whether 

 reserve food-material occurs; whether the flowers are formed 

 the year previous to that in which they open. 



2. Spring phenomena. 



3. Flowering phenomena: the biology and the shade of colour 

 of the flower; the visits of insects to the flower. 



4. Fructification ; phenomena connected with the fall of the leaf; 

 dispersal of seed. 



5. Observations of the humidity of the air; the temperature of 

 the snow, soil, water and air (in the sunlight and in the 

 shade). 



6. The formation of mycorrhiza. 



7. Investigations of carbon-assimilation. 



For further references see loc. cit. 



It may, moreover, be stated that, of the two undersigned, 

 Ostenfeld has revised the determination of the species, while 



