1915] 



WILLE FLORA OF NORWAY 71 



places is also much more abundant, and the ordinary lowland 

 flora may be found fairly well represented. 



Almost all cultivated land in Norway lies in the Oak and 

 Pine Zones. Rye and oats ripen up to latitude 69°N., barley 

 even up to 70 °N. — in the south it can be grown up to a height 

 of 2,066 feet above the sea. The potato is cultivated rather 

 farther north and a little higher above sea-level than barley. 

 Side by side with the growing of grain is that of forage 

 plants, of which the most important species are Trifolium 

 vratense and Phleum vratense. 



III. THE BETULA ODORATA ZONE 



Betula odorata also occurs in the lowlands, and extends 

 farther toward the sea than Pinus sylvestris, but by its zone, 

 as here defined, is meant the region above the height limit of 

 Pinus sylvestris upon the mountains and north of its distri- 

 bution. In the very south of Norway, Betula odorata goes up 

 to about 3,600 feet above the sea, and northward as far as 

 latitude 71° 10' N. Thus beyond the Birch Zone there is only 

 the northeastern part of Finmark and the highest mountain 



regions. 



In the south of Norway the great proportion of the so-called 

 "saeters" lies in the Birch Zone, as this tree generally oc- 

 cupies the margin of the mountain wastes, and fills the little 

 valleys that intersect them with a short-stemmed forest of 

 Betula odorata subsp. alpigena. 



Side by side with this mountain form of birch, there may 

 also grow Alnus incana, Populus tremula, Prunus Padus and 

 Sorbus Aucuparia. The ground vegetation will be somewhat 

 variable according to the degree of moisture in the soil. 



On dry gravelly slopes, especially if they face the south, 

 the following species of higher plants are generally found 

 in addition to a few species of lichens, such as Cetraria island- 

 ica, Stereocaulon, etc. : Arctostaphylos officinalis, Agrostis 



fl 



A. vulgaris var. 



pubescens, Antennaria dioica, Anthoxanthum odoratum 

 Astragalus alpinus, Botrychium Lunaria, Betula nana, Call 

 una vulgaris, some species of Car ex, Empetrum nigrum 



