ALPINE PLANTS AND THEIR TREATMENT. 



110 



they grow in a natural state. These conditions are not, of 

 course, to be found in a lowland climate ; but it is possible in 

 many respects to supply them by artificial means. And in the 

 search for and application of these means lie all the secrets of 

 successful cultivation. 



The first condition of growth for Alpines, as for all other 

 plants, is a certain degree of heat. If the thermometer never 

 rise above the freezing point, the sun may flood the landscape 

 with its light without producing any movement of vegetable life, 

 even supposing that the soil were free from snow and ice. But 

 whilst a considerable increase of warmth is necessary to bring 

 the plants of the plains into growth and flower, it is quite other- 

 wise with the plants of the Alps, as the smallest degree of heat 

 above the freezing point wakes them at once into active life. 

 The vegetation of the upper zones is subjected to a much more 

 severe treatment, and enjoys a summer so short and so cool 

 that it might almost be said to represent winter for the plants of 

 the plains. These Alpine species, however, accomplish during 

 this short space of time the complete cycle of their annual 

 existence. They flower and ripen their seeds as well as do the 

 lowland plants ; and their stunted habit, the shortness of their 

 stems, and the smallness of their foliage evidently contribute to 

 quicken and awaken life, by sending to the flower and to the 

 reproductive organs all the sap conveyed to the plant by its 

 numerous roots. 



It is necessary, however, to remember that under the condi- 

 tions to which the Alpine flora is subjected it enjoys an ardent 

 and intense warmth, from the fact that the solar rays shine 

 longer and more continuously upon it, and that the thickness of 

 the atmosphere is less than in the lowlands. But if during the 

 day, and when the sun exercises its influence, the vegetation 

 enjoys a greater degree of warmth, it has, on the other hand, to 

 endure cold and rigorous nights, during which the thermometer 

 sometimes descends to 18 or 20 degrees Fahr. below freezing. 



Another essential condition to rapid growth is light ; and it 

 is, after warmth, the chief element in which the Alpine flora 

 revels. At a great altitude nature is far more prodigal of light 

 than in the plains. At the very commencement of its growth 

 the Alpine flora is immediately benefited by the same amount 

 of light that the plants of the plains receive in the summer. 



