OF PERTHSHIRE AND BRAEMAR. 315 



lected : thus, among the fungi, not only do we see frequent 

 additions of microscopic, but occasionally also the reader 

 is astonished by the announcement of hitherto overlooked 

 species of large size ; in the lichens, the additions of the 

 last seven or eight years must much exceed a hundred 

 species ; and even in the mosses, the most fully investigated 

 group of the three, they may be counted by dozens. 



The mosses, though possessing little economic value, 

 yet serve both for a quiet and pleasing adornment of rocks, 

 walls, &c., and also in the most barren situations prepare a 

 slight soil for the development of higher organisms. Every 

 different situation is more or less distinguished by the 

 presence of certain genera. On newly turned soil Phascum, 

 Weisia and Pottia prevail ; on walls, Trichostomum, Tortula, 

 Bryum, Rhacomitrium ; on trees, Orthotrichum, Zygodon\ 

 in bogs. Sphagnum, Hypnum, and numerous other genera ; 

 and on rocks a multitude of genera and species, which, 

 again, increase greatly in number with a higher elevation. 



Three alpine regions in Scotland stand preeminent for 

 the variety of their mosses: — ist, Ben Lawers, in Perth- 

 shire, with the adjoining peaks ; 2nd, the Clova District, 

 in Forfarshire ; 3rd, Braemar. All these were long since 

 searched by able botanists, as Hooker, Gardiner, Drum- 

 mond, Wilson, Arnott, Greville, and others ; but such is 

 their richness, that a year hardly ever passes without some 

 discovery. There are several causes for this richness, e.g. 

 elevation, moisture of climate, and nature of soil. 



Ben Lawers is situated on the north of Loch Tay, and 

 attains an elevation of 3984 feet above the level of the sea : 

 it is the highest point in Perthshire. Its lower slopes con- 

 sist of extensive moors, interspersed with peat-bogs, and 

 here and there crossed by rocky streams, which have cut 

 deep channels for themselves through the moors. On the 

 upper parts of these slopes, in bogs, occur the following 

 mosses (at an elevation of from 2500 to 3000 feet) : — 



