1917.] THE FLORA OF THE SWISS ALPS 33 



the highest Swiss mountain, the Monte Rosa, at 15,217 feet. There is 

 indeed no real upward limit of vegetation in the Alps. 



A short excursion through some characteristic parts of the coun- 

 try will show us the principal steps in the change of the vegetation. 

 We begin in the lake region at the southern foot of the Alps, where 

 we find the mildest climate in Switzerland. At the shores of the 

 lakes of Locarno, Lugano, and Como, the Italian cypress (Cupres- 

 sus sempervirens L.) brings us a greeting from the Mediterranean 

 countries (Fig. 12). 



Then we enter the beech forests, and admire the mighty crown 

 of this dominant tree (Fagus sylvatica L.) of the mountain belt ; the 

 group shown in Figure 13 grows near Flims in the Oberland of 

 Grisons, and is renowned for its luxuriant growth. 



From the top of the Piz Mundaun in the same Oberland of 

 Grisons we cast a glance at the slopes of the valley of the Upper- 

 Rhine, where the coniferous belt (Picea excelsa Link) is seen in its 

 whole extension, surrounded at its foot by woods of oak, and trans- 

 grading upward into the alpine belt (Fig. 14). This dark-green 

 girdle, formerly continuous without any doubt, has been partly de- 

 stroyed by human action, and shows now many interruptions filled 

 with corn-fields, meadows, and pastures — that is, various culture 

 and semiculture formations. 



The Scotch Pine (Pinus sylvestris L.) with its flattened crown 

 is the tree of our very poorest soils, where it adorns rocky or sandy 

 slopes, as is shown in our picture taken near the Campodials in the 

 Grisons (Fig. 15). 



In the Central Alps, especially in the Upper Engadine and Wal- 

 lis, the Spruce is upwardly replaced by a tree of the continental 

 climate, the Larch (Larix decidua Miller), forming open woods with 

 so slight a shade as to allow the occurrence of a good pasture under 

 the trees. Thus those larchwoods form an ideal solving of one of the 

 most intricate economical problems of the Alps, the cause of an end- 

 less conflict between forester and alpine farmer. And at last we ad- 

 mire in the Central Alps, for instance at Zermatt or Engadine, an- 

 other continental tree, the Arolla Pine, the Siberian Cedar, the king 

 of the alpine trees (Pinus cembra L.), which forms often the tim- 

 ber-line (Fig. 16). 



And now we reach the limit of tree-growth, this most important 

 biological line, which separates the Arctic region and the alpine 

 belt from milder climates. It is not a line; it is a girdle where the 

 tree struggles for its life (Kampfzone, struggle belt). First we leave 

 behind us the continuous wood (Forest-limit), then the isolated pi- 

 oneers of trees (Tree-limit), and^fmally the stunted forms of trees 

 (Cripple-limit). 



In and above this belt of struggling tree-life lies the belt of al- 

 pine shrubs; the Alpenrose (Rhododendron), the green Alder (Al- 

 nus viridis (Chaix) Lam.), and the dwarf Pine (Pinus montana 



