RECENT DISCOVERIES IN THE SOUTH NORWEGIAN FLORA 251 



The "survival" — or "refugium" — theory has lately been subjected to a 

 rather rough criticism from several Norwegian and Swedish Quaternary 

 geologists. They clamor distinct proofs for the existence of ice-free areas 

 along the Norwegian coast as well as for nunataks farther inland. Other 

 geologists do not totally deny the "refugium theory"' but prefer to remain 

 passive. 1 will here stick to the plants and their distribution, and especially to 

 the distribution of the bicentric mountain species. Norwegian and Swedish 

 botanists have cooperated conscientiously during the last generation, I dare 

 say even to their utmost, in order to investigate in full the geographical 

 distribution of the bicentric species. The result is that the bicentricity is a fact 

 for a number of species. On the whole, it is possible to state that the botanical 

 indicia in favor of the survival theory have increased, and many previously 

 unknown conditions have been brought into light (cf. Elfstrand, 1927; 

 Ekman, 1927; Nordhagen, 1930, 1936, 1940, 1952, 1954, and others). 



In order to explain the bicentricity some authors have resorted to the 

 Post-glacial Hypsithermal period. It caused a strong displacement north- 

 wards and upwards of the Piniis silvestris forests, and the authors in question 

 maintain that the presently bicentric mountain species had a continuous 

 distribution in the Norwegian-Swedish mountains before this warm time. 

 The cause of the present bicentricity should be that precisely the area from 

 north Trondelag to Saltdal in Nordland County consists of mountains reach- 

 ing a lower altitude than those to the south and the north of it, and thus 

 largely were covered in the Hypsithermal by Pinus silvestris forest which due 

 to its shading effect obliterated the light requiring bicentric species from this 

 area. Such an explanation is, however, unacceptable. A great many of the 

 bicentric species are today found right inside the upper reaches of the Pinus 

 silvestris belt. Saxifraga hieraciifolia offers a good example. It was found 

 already in the 1870's at an altitude as low as ca. 600 m above sea level at 

 Lake Olstappen in the eastern part of Jotunheimen. One of the botany 

 students at the University of Oslo, Sverre Lokken, has recently discovered it 

 at only 450 m altitude in a river gorge at Garmo, inside the Piims-hQ\i, in the 

 northern part of Jotunheimen. The finds from Olstappen and Garmo are 

 very important. It is evident that Norway had also during the Hypsithermal a 

 very broken relief with eroding rivers, gorges and lakes. Thus, if in recent 

 times a plant like Saxifraga hieraciifolia can occur not only above the timber- 

 line, but also here and there at a lower altitude, down to 450 m, inside the 

 Pinus region, a displacement upwards during the Hypsithermal of the Pinus 

 silvestris forests cannot possibly be used to explain the bicentricity of this 

 species. Below I will discuss the relationship between the bicentric Rhodo- 

 dendron lapponicum and the Pinus forests. 



The survival theory postulates first and foremost that there were ice-free 

 refugia along the coast of More in southern Norway (Undas, 1941), and from 

 Saltdal and Lofoten to west Finnmark in northern Norway (Holtedahl, 1929; 



