989 



is in agreement with their preference for the warmest and most 

 favourable piaces on the Færoes. 



The piants of this formation fruit fairly well, with some ex- 

 ceptions, thus Chamaeneriiim angnstifoliiim which frequently does 

 not even come inlo bloom (cfr. Ostenfeld 1907, p. 851); this may 

 also happen with Riihiis saxatilis (see p. 91(3). The dicotyledons 

 are all entomophilous, if not self-poUinated^; the flowers are con- 

 spicuonsly coloured, blue, reddish-purple, yellow and white being 

 represented (e. g. Polijgala, Geranium, Alector olophiis, Spiraea, etc). 



3. Alpine formations. 



The geological structure of the mountains is such that in al- 

 most every case the summit is flattened and forms a plateau, from 

 which the mountain flanks fall away towards the ocean or some 

 Valley in a succession of terraces, the home of the cliff-vegetation 

 already described. The broader lerraces may also be regarded as 

 plateaux occurring on a lower plane than the actual summils, but 

 the narrower terraces fall in with our conception of ledges and 

 slopes. 



In this higher region of the Færoes, or what may be cailed the 

 alpine region, we find the following plant-formations: 

 1 °. On the slopes and ledges, and in the ravines: 



a) Grass-slope formation, b) Lithophyte formation, c) Chomo- 

 phyte formations; the last generally being present as the 

 typical chomophyte formation, less frequently as the om- 

 brophile, and very rarely as the thermophile. 

 2°. On the plateaux or flåts: 



a) Lithophyte formation, b) Rocky-flat formation, c) Alpine-bog 

 formation, d) Grimmia-heath. 



The second group of formations, the vegetation on the flåts of 

 the mountain-plateaux, alone will be dealt with here. The other 

 alpine formations (Group 1°) we have already included under our 

 descriptions of the grass-slope and the cliff formalions. 



The plateaux are siluated at different altitudes ranging from 

 200—300 m. above the sea-level, upwards to 700—800 m., the 

 highest. The vegetation is essentially of the same character, although 

 it decreases in luxuriance and in wealth of species as the highest 

 levels are reached. 



^ All the Hieracia are apogamic. 



