ANTHELIA: AN ARCTIC-ALPINE PLANT ASSOCIATION 8l 



Anthelia : An Arctic-Alpine Plant Association. 

 By W. G. Smith, B.Sc, Ph.D.i 



In the course of the ascent of Ben Lawers by the Inter- 

 national Phytogeographical Excursion last August, Professor 

 C. Schroter and Dr. E. Riibel, two experienced Swiss 

 botanists, pointed out a plant association extremely 

 characteristic of the higher Alps. This association presents 

 many points of interest as one in which several Hepaticae 

 and Mosses play the part of pioneers in colonising a sub- 

 stratum which owes its origin in the first place to topography 

 and in the second place to the action of running water. 

 While the term "arctic-alpine zone" in Scotland is a con- 

 venient term for general use, most botanists will appreciate 

 that the zone is by no means uniform in its development. 

 Just as the vegetation of the lowlands presents itself as 

 woods, moors, grassland, and other types, each with sub- 

 types, so in the arctic-alpine zone there are m,any sub- 

 divisions (i) (2). The plant association now under con- 

 sideration is one of these subdivisions, and it is proposed to 

 bring together here some information which may direct 

 attention to it and may stimulate the study of others. 



Last August on Ben Lawers, after ascending the morainic 

 valley of the Tuim Bruic or Carie Burn, and traversing in 

 succession the zones of Nardus-Juncus sqiiarrosus grassland 

 and the Alchemilla alpina pasture, the lower levels of the 

 south-west corries were reached. Shortly after leaving the 

 clear springs which emerge from the rocks about 3000 feet 

 at the highest limit of a definite stream channel on the 

 Lawers side of the valley, the Swiss botanists drew attention 

 to a long, dark, crusted tract descending from near the 

 base of the "Gentian Cliff," a very conspicuous tract in 

 the rock-strewn green sward of this part. Other examples 

 were seen in ascending the slope towards the low neck between 

 Ben Lawers and B. Ghlas, frequently as dull dark stretches 

 following a series of shallow troughs. Towards the summit 

 the grassy turf becomes more limited, and AlcJiemilla alpina is 



' Read before the Botanical Society of Edinburgh, llth April 1912. 



