772 ZONES AND REGIONS [Pt. Ill, Sect. IV 



meters. A greater humidity in summer in the higher stations causes 

 the appearance of summer-green oak-forest (Q. Kellogii) ; sandy and 

 gravelly soil is dominated by the accommodating pines (Pinus ponderosa). 

 The upper moist and cool belt of the montane region is occupied by the 

 most magnificent mixed coniferous forest in the world, and is the home 

 of Sequoia gigantea. An account of these forests has been already given. 

 Regarding the alpine region there are no data. 



In the Chilian sclcrophyllous district the atmospheric precipitations do 

 not suffice, even on the mountain sides, to evoke a stronger vegetation ; 

 the poor xerophilous vegetation passes over into the still poorer vegetation 

 of the mountain desert or puna. Only on Frai Jorge, a peak in the 

 otherwise thoroughly dry province of Coquimbo, has a constant belt of 

 clouds, just as in the Canaries, afforded conditions for the existence of 

 temperate rain- forest, even if in an attenuated form. This forest is also 

 systematically allied to the rain-forest of Valdivia. Its most important 

 trees are Aetoxicum punctatum and Drimys chilensis 1 . 



3. THE REGIONS IN THE COLD TEMPERATE BELTS, 

 i. SWITZERLAND. 



Among the mountains of the northern cold temperate zone the Swiss 

 Alps have in all respects been botanically studied in the fullest detail. 

 H. Christ 2 has presented a picture of the vegetation of the Swiss Alps 

 which is complete in its leading features, and now requires only to be 

 continued in detail in the physiological direction already indicated by him 

 in order to be rendered as perfect as at present possible. 



The following tabular statement is not universally applicable, and serves 

 only to give the general orientation ; the stages enumerated in it are rarely 

 all present : — 



AVERAGE MOUNTAIN REGIONS ON THE SWISS ALPS. 



Meters. 

 Basal Region 550-700 



Montane Region. 



Chestnut-forest (South Switzerland) up to 900 



Beech-forest „ 1,200 



Spruce-forest 800-1,800 



Larch and Cembran pine (Central Alps) up to 2.100 



Alpine Region. 



Pinus Pumilio and Alnus viridis 2,coo 



Rhododendron up to 2,120 



Juniperus nana „ 2,500 



Herbs and dwarf-shrubs up to the summits. 



(Snow-limit 2,700-3,000 meters.) 



1 F. Philippi, op. cit. 2 Christ, II. 



