1905-1906.] Scottish mountain Plants. .251 



concern us just now are — the Super-agrarian zone, char- 

 acterised by the Bracken (the higher limit of this fern is 

 usually the limit of cultivated ground) ; the Infer - arctic 

 zone, Erica Tetralix without Bracken ; Mid-arctic zone, Heather 

 (Calluna) without Bell Heath (Erica Tetralix) ; Super-arctic 

 zone, a dwarf Willow (Salix herbacea) without Heather. The 

 exact height reached by any particular plant may vary even 

 on the different slopes of the same mountain, for the height 

 attained on the southern side is often greater than on the 

 northern. Aquatic plants are by no means so easily affected 

 by the mountain climate as are land forms, and therefore 

 afford little criterion of elevation. In the higher zones 

 climbers are conspicuous by their absence. The Wood 

 Vetch (Vicia sylvatica) and the Stone Bramble (Eubus 

 saxatile) scramble over rock ledges, but the former occurs 

 in greater abundance lower down. Annuals (as Gentiana 

 nivalis) are rare. 



It may be interesting to group together informally some 

 of the more conspicuous types of our native mountain plants, 

 making no aim at completeness, and always remembering 

 that mountain floras are usually as heterogeneous in com- 

 position as lowland ones, and cannot be divided up into a 

 few strictly defined groups. 



Forest Trees. — The lower slopes are frequently covered with 

 woods of Scots Pine, Larch (not indigenous). Birch, &c. 

 The rearguard of such forests is usually the Pine, as this 

 tree withstands wind and cold comparatively well. Where 

 isolated clumps of trees occur, their growth is often stunted. 

 Beneath the woods or forests of mountainous districts such 

 plants as Vaccinium Myrtillus, Linnsea, Pyrola, Goodyera, 

 various Ferns, &c., may occur. In Continental woods similar 

 plants are found, together with the Lady's-slipper Orchid 

 (Cypripedium Calceolus) and others. The growth of forests 

 is encouraged by a considerable amount of atmospheric and 

 also surface moisture. 



Tall Herlaceous plants are more commonly observed at 

 low elevations, but they also occur at considerable heights, 

 especially where there is more shelter than usual. They 

 then form a noticeable feature, among a herbage so generally 

 dwarf. The most frequent plant of this description in Scot- 



