40 TRANSACTIONS OF THE [Sess. lxxvi. 



in Spitzbergen. Riibel (7) follows the Scandinavian 

 botanists in distinguishing an " Anthelietum," which he 

 regards as the basis of the snow-flush types of vegetation 

 to be indicated later. It is thus clear that experienced 

 observers in Northern Europe and the Alps recognise in 

 A. Juratzkana one of the pioneers of the snow-flush. 



Another cryptogamic element in the snow-flush vegeta- 

 tion is the genus Polytrichum, according to the Swiss 

 accounts generally P. sexangulare, Flork., and P. alpinum, 

 L., two species recorded as characteristic of the summit 

 region of Scottish mountains. On Ben Lawers we saw 

 cushions of Polytrichum (sp. not identified) in the snow- 

 flushes pointed out. This genus of mosses has several 

 species which are adapted for life in moorland flushes, as 

 indicated by C. B. Crampton [ (2) p. 62]. They can with- 

 stand periodical submergence and soon grow through the 

 shallow deposits of sediment laid down, so that they aid 

 in binding these deposits into a humous turf ; the close, 

 compact growth also enables the tufts to withstand periods 

 of drought. 



The snow-flush vegetation includes a limited number of 

 flowering plants, but according to Swiss accounts some 

 of these are very characteristic. The following is a list 

 of species recorded in August 1911 {i.e. after a dry summer) 

 on the western slopes of Ben Lawers (about 3500 feet) in 

 two snow-flushes where Anthelia was a conspicuous 

 element : 



Polytrichum. Gnaphalium supinum. 



Rhacomitrium lanuginosum. Salix herbacea. 



Solorina crocea (orange lichen). Sibbaldia procumbens. 



Carex pilulifera. Euphrasia (? scotica). 



C. rigida. Festuca ovina (vivvpard). 



A short list was recorded (August 13, 1898) by Robert 

 Smith on Ben-y-Ghloe at about 3000 feet on patches where 

 snow had recently melted : — Salix herbacea, Gnaphalium 

 svupinum, Alchemilla alpina, Galium saxatile. 



The Swiss " Schneetalchen" is thus described (3) : — " Poly- 

 trichum septentrionale usually appears as a pioneer and 

 covers the ground with a dense, dark-green carpet. Soon 

 afterwards Arenaria bifiora begins to penetrate this carpet ; 



