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Strandmark, P. W., (1880): Blomställningen hos Empetrum nigrum L. 

 Bot. Notiser. 



Sylvén, N., (1906): Om de svenska dicotyledonernas första förstärknings- 



stadium. Kgl. svenska vet. akad. handl. Bd. 40. 

 Volk ens, G., (1912): Laubfall und Lauberneuerung in den Tropen. 

 Wagner, A., (1892): Zur Kenntniss d. Blattbaues d. Alpenpflanzen und 



deren biol. Bedeutung. Sitzber. d. k. Akad. d. Wiss. in Wien. Mat.- 



nat. Cl. C. I, Abth. 1. 

 Warming, E., (1878): Smaa biologiske og morfologiske Bidrag. Bot. 



Tidsskrift. 10. 



Warming, E., (1881): Om Skudbygning, Overvintring og Foryngelse. 

 Nath. Forenings Festskrift. 



Warming, E., (1886—87): Om Grønlands Vegetation. Medd. om Grøn- 

 land. XII. 



Warming, E., (1887): Biologiske Optegnelser om grønlandske Planter. 



Bot. Tidsskrift. Bd. 16, Hf. I. 

 Warming, E., (1888): Biol. Optegnelser om Grønlands Planter. 2. Bot. 



Tidsskrift. 16. 

 Warming, E., (1895): Plantesamfund. 

 Warming, E., (1912): Frøplanterne. 

 Warming, E., (1916—19): Dansk Plantevækst 2 og 3. 

 Wichura, (1816) : Beiträge zur Lehre von der Blatt- und Knospenstellung. 



Flora. 29. 



Winkler, H., (1901 og 1903): Untersuch, zur Theorie der Blattstellungen, 

 I og II. Jahrb. für wiss. Botanik, Bd 36 og 38 



On Empetrum nigrum. 

 Summary. 



According to the dominating shrubs the vegetation of the heaths of 

 Jutland may be divided in the following 6 formations: 



No. 1. Oxycoccus-Formation (comp. Olsen (1914) p. 27). 

 No. 2. Mï/n'm-Formation (comp. Raunkiær 's table (1910), column 1). 

 No. 3. £Wca-Formation (comp. Raunkiær 's table (1910), column 2). 

 No. 4. Empetrum-F oim&tion. (comp. Raunkiær 's table (1910), column 3). 

 No. 5. A rctostaphylos-F oi mation (comp. Raunkiær 's table (1910), columns 



4 and 5). 



No. 6. OaZfoma-Formation (comp. Raunkiær's table (1910), column 6). 



Of these formations No. 1 grows at the lowest level and No. 6 at the 

 highest. In formation No. 6 Empetrum has its maximum and it is here the 

 dominating species. If we go to higher or lower levels this plant gets more 

 and more rare and is at last missing in the Calluna- and 0.z?/coccMS-formation. 

 If burnt ofï, Empetrum regenerates very slowly (because only very few 

 seeds are able to germinate). 



The fruits are largely eaten and dispersed by various animals: birds, 



