686 Rydberg: Phytogeographical notes 



Alpine vegetation 



After having discussed the causes of the timber line, it is easier 

 to define what an alpine plant is. In short, it is a plant that can 

 endure the climate of the mountains above the timber line. It is 

 a plant that requires less heat during the growing season than the 

 forest trees, or that can survive a shorter growing season, or is 

 less affected by frost, and besides can better withstand desiccating 

 winds, deep snow, reduced precipitation, etc., or a combination of 

 such conditions. Some authors claim that alpine and arctic 

 plants are xerophytes, but they are not necessarily so. While 

 most of the plants of alpine and arctic regions can withstand a great 

 deal of drought, in fact are xerophytic plants, it is not the case with 

 all. Not a few of the arctic-alpine plants require a great deal of 

 moisture, growing only below and around snowbanks, or in springy 

 or boggy ground, as for instance several species of Ranunculus, 

 Saxifraga (in extended sense) , Sahx, and many grasses and sedges. 

 There are in the arctic-alpine regions even true aquatics, as for 

 instance among the phanerogams, Catabrosa aquatica, Phippsia 

 algida, Sparganium minimum, and S. hyperboreum, and a few species 

 of Potamogeton. 



New York Botanical Garden 



