HARDWICKE'S SCIENCE-GOSSIP. 



49 



BOTANICAL NOTES FROM THE SWISS HIGHLANDS. 



II. ZONES OF VEGETATION : THE RIGI. 



■ E distinguish be- 

 tween a vegeta- 

 tion of the plains 

 and one of the 

 hills : similarly 

 there is a differ- 

 ence between a 

 subalpine flora 

 and that which is 

 purely alpine. But 

 it is difficult to 

 draw exact lines 

 of demarcation be- 

 tween any fixed 

 number of botani- 

 cal zones, which 

 sliall coincide with- 

 out exception with 



IliW^flffS 1"^'^M^ those which we 



lil'llj^'l * ^ '^^^ i-[jay agree to re- 



gard as correlative 

 geographical ones. The zones overlap each other. 

 We must therefore meet the difficulty half way by 

 supposing a conical figure, which shall represent a 

 high mountain rising from a low level, upon which 

 botanical zones are described as proceeding obliquely 

 frotn side to side and intersecting diagonally the 

 horizontal geographical ones. 



In considering the subject generally, due account 

 must be taken of difference of latitude. Thus a 

 plant — Azalea prociimbens, for instance^rarely found 

 on the Swiss Alps under 6000 feet of altitude occurs 

 on the Scottish Highlands at 4000. These figures, 

 therefore, would be equivalent terms, in this sense. 

 Crossing the Brunig Pass some years ago, we found 

 this plant on a boulder near the summit. The pass 

 is under 4000 feet ; we may infer, therefore, that the 

 boulder had been detached at some past time from 

 an overhanging height. 



Let the beech limit be assigned to the hilly zone 



of Switzerland, that of the pines to the subalpine 



one, and the upper regions of prevailing cloud and 



mist to that which is truly alpine ; or thus, to be 



No. 195.— March 1881. 



more precise : hilly zone, 2500-4000 ; subalpine, 

 4000-5500 ; alpine, 5500 to snow-line. 



Although genera of plants occur in these upper 

 regions which are peculiar to them — androsace, bis- 

 cutella, oxytropis, for instance — the difference never- 

 theless is for the most part merely one of species — 

 perhaps in some instances one of starved, stunted, 

 abnormally hairy or pubescent variety — while a much 

 larger proportion of plants, both generic and specific, 

 alien to our British flora, such as arnica, bellidia- 

 strum, cerinthe, coronilla, cynanchum, &c., are 

 restricted to the hilly or subalpine zones of which 

 they are denizens. On the other hand, plants re- 

 garded as strictly alpine are occasionally found low 

 down the flank or at the base of a high mountain. 

 In such cases they are either of boulder origin, or 

 their seeds have been washed down by torrents and 

 deposited in localities otherwise congenial for their 

 germination, where they flourish and display not 

 unfrequently under these new conditions of existence 

 a luxuriance of growth foreign to their highland 

 habit : thus, Btipkunim raniiiicnloides, a humble 

 little plant, three or four inches high on the grassy 

 declivities above the pines, will attain proportions of 

 two and a half feet ; and the same remark applies to 

 Cochlearia saxatilis, Thalictriun alpiniun, Athamanta 

 cretensis, and others. Even the rhododendron may 

 occasionally be gathered at the foot of a mountain. 

 One locality of the kind is low down a promontory 

 of the Beatenberg, on the northern shore of the lake 

 of Thun. 



A line drawn from the point where the Rhone 

 enters the lake of Geneva to that where the Rhine 

 falls into the Bodensee will traverse the central 

 lakes of Switzerland. Let this be regarded from a 

 geographical point of view as a subalpine belt, with 

 an average width of twenty miles or so, which shall 

 serve as a boundary line between the hilly zone on 

 the one side and the alpine one on the other ; a chain 

 of mountains which forms as it were an advanced 

 guard to those snowy ranges which attain their 

 greatest elevation along the southern frontiers of 

 the country. It is within the confines of this belt 



D 



