36 TRANSACTIONS OF THE [Sess. lxxvi. 



Anthelia: An Arctic- Alpine Plant Association. 

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



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 char- 

 acteristic of the higher Alps. This association presents 

 many points of interest as one in which several Hepaticse 

 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 

 convenient 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 

 many subdivisions (1) (2). The plant association now 

 under consideration 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 squarrosus grass- 

 land 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 Alchemilla alpina is more and 



