1915] 



WILLE FLORA OF NORWAY 67 



Spiraea Filipendula, Thymus Chamaedrys, Trifolium mon- 

 tanum, Veronica spicata, etc. 



Where the soil is deep and not too dry, the above-mentioned 

 deciduous trees that are susceptible to cold form forests or 

 copses, intermingled with Corylus Avellana, Prunus spinosa, 

 species of Rosa and Rubus, and a luxuriant ground vegeta- 

 tion, among which are several orchids. 



A few of these trees and the more hardy species of the 

 Silurian flora, such as Origanum vulgare and others, may, like 

 an advance-guard, overstep the boundaries of the Silurian 

 regions, but then they generally occur in warm localities, in 

 talus at the foot of cliffs, or in steep slopes that face south- 

 ward, even high up the sides of the valleys, or in the upper 

 parts of the West Country fjords. 



But the number of species diminishes with increasing dis- 

 tance from the lowland Silurian regions, and there are only a 

 few species that have advanced as far as north of the Dovre 

 Mountains. 



2. The Region of Fagus sylvatica. — This region is situated 

 along the southeast coast of Norway, from the Swedish border 

 to Grimstad, where it extends as far north as Holmestrand. 

 There is a small beech-wood a little to the north of Bergen, 

 but this is a solitary instance, and has nothing to do with the 

 real distribution area of the beech. 



The beech is purely a lowland plant, as there is only one 

 place in which it goes to a height of 886 feet above the sea, 

 its usual height being not more than 525 feet. When culti- 



& u " uv,iu & 



vated, it can grow almost as far north as Quercus pedunculata, 

 but prefers a rather higher summer temperature (13.4°C.) 

 and thrives best on comparatively warm gravel banks. 



The beech is one of those plants which has recently ap- 

 peared to spread to new regions ; and there is no doubt that 

 it has not yet nearly reached the limits of distribution to 

 which it will little by little attain, especially along the low 

 land of the south coast. This is due to the fact that it must 

 have immigrated in fairly recent times. 



The following plants may also be mentioned as occurring 

 chiefly in the region of the beech : Cladium Mariscus, Cor on- 



