78 



species have been mutually compared. As mentioned above, the 

 anatomy of the greater number of the plants has already been 

 described, but I am of opinion that the present work would become 

 too superficial if I merely referred in it to these descriptions. I have 

 treated each species according to a certain fixed plan and this I 

 have preferred to employ with regard also to those species which 

 have previously been described elsewhere, hi the present paper 

 they will all be compared with each other and that by a single 

 author who must necessarily have some definite starting point. Only 

 in the case of Cassiope tetragona, upon which a small monograph 

 has already been published, have the main points of structure been 

 dealt with superficially. 



It is chiefly the leaves and the stems which are here described, 

 these organs being of the greatest importance in a biological, climato- 

 logical connection. The roots, which occurred but sparingly in the 

 material, have been investigated only for the sake of the mycorhiza, 

 in the cases where this was possible. The bud-scales have not 

 been examined at all. No . attempt has been made towards 

 giving a systematic anatomical account. The photographs of the 

 transverse sections of the stems have been taken by Mr. A. Hesselbo. 

 The illustrations have been drawn partly by Professor Warming and 

 partly by me. The material consisted chiefly of specimens preserved 

 in spirit, and was all from the Botanical Museum in Kjöbenhavn; 

 it had been collected over a long period by different naturalists. 



The following is a list of the chief literature: • — 



Abromeit, J., 1899, Botanische Ergebnisse der .... unter Leitung Dr. v. Dry- 

 galski ausgesandten Grönlandsexpedition. B. Samenpflanzen (Phanero- 

 gamen). (Bibliotheca botanica, 42. Stuttgart.) 



Ambronn, H., 1890, Allgemeines über die Vegetation am Kingua-Fjord. (Die 

 internationale Polarforschung 1882 — 83: Die deutschen E.xpeditionen und 

 ihre Ergebnisse, Bd. II, p. 61, Berlin, 1890.) 



Bonnier, G., 1894, Les plantes arctiques comparées aux mêmes espèces des 

 Alpes et des Pyrénées. (Revue gén. de Botanique, T. VI.j 



Breitfeld, H., Der anatomische Bau der Blätter der Rhododendroideæ. (Engl, 

 bot. Jahrb. Bd. 9.) 



BöRGESEN, F., 1890, Nogle Ericiné-Haars Udviklingshistorie. (Botanisk Tids- 

 skrift, Bd. 17.) 

 — 1895, Bidrag til Kundskaben om arktiske Planters Bladbygning. (Bota- 

 nisk Tidsskrift, Bd. 19.) 



Hesselman, H., 1900, Om Mykorrhizabildningar hos arktiska vaxter. (Bihang 

 till К. Sv. Vetensk. Akad. Handlingar, Bd. 26, Afd. III, Nr. 2.) 



