7o8 



ZONES AND REGIONS [Pt. Ill, Sect. IV 



2^ 



hand, the alpine form of Parnassia palustris x has much smaller flowers than 

 the lowland plant. The scent of the flowers increases with the altitude. 



To the general characters of alpine vegetation, in the alpine regions of 

 temperate mountains, are added others due to the shortness of the vegetative 

 period. These are most strikingly exhibited in species that are common 

 both to the lowlands and to the mountains. Thus, flowers of Calluna, 

 Parnassia, Gnaphalium dioicum, Gentiana germanica, Solidago Virgaurea, 

 Dianthus superbus, open in August on the hills, but in July in alpine regions, 

 although the vegetative season in the latter commences much later 2 . 



The question how far the characteristics of alpine plants that have just been 

 enumerated are to be considered as the direct effects of the mountain climate 



has been partly solved by 

 the experiments of A. von 

 Kerner and Gaston Bon- 

 nier, who cultivated low- 

 land plants in a mountain 

 climate. As Bonnier's ex- 

 periments appear tobe most 

 free from objection, preced- 

 ence will be given to them, 

 though they are of later 

 date than those of Kerner. 

 Bonnier's experimental 

 cultures at the greatest 

 altitudes were carried on in 

 the Alps (Aiguille de la Tour) at 2,300 m., and in the Pyrenees (Col de la 

 Paloume) at 2,400 m. ; the control cultures in the lowlands were in the imme- 

 diate and more distant neighbourhood of Paris, as well as in the Departement 

 du Gex. Several intermediate stations, for instance at 740 meters and at ] ,050 

 meters (Chamonix), were also utilized for cultures. In each series of experi- 

 ments the same soil, taken from the mountain station, was used, and, to 

 obviate individual variations, in perennial plants vegetative members of the 

 same stock were used, and in annuals, seeds of the same plant. In all the 

 cultures the mountain climate caused changes in external and internal 

 structure, by which lowland plants acquired a more or less decided, but 

 always evident, alpine habit. The subterranean parts acquired, at least 

 relatively, a stronger development. The axes became shorter, more hairy, 

 and displayed a tendency to spread out horizontally. The leaves were 

 smaller, thicker, more hairy, and richer in chlorophyll. The flowers were 

 larger relatively, and often even absolutely (Solidago Virgaurea, Carduus 



1 Compare, for instance, the flowers of Parnassia on the Schynige Platte and at 

 Interlaken. 

 a See Sendtner, op. cit., p. 289. 



' r -^ 



F]G. 410. Alpine flora of the Andes. Perennial rosette-plant. 

 New Grenada to Pern. 3,000-4,000 m. Achyrophorus qui- 

 tensis, Sch. Bip. Two-thirds natural size. 



