THE CLASSIFICATION OF COMMUNITIES 365 



Table 41. — Order of the Caricetalia Curvulae 



In addition to the numerous characteristic species of the component 

 alhances and associations of the CaricetaUa curvulae, we may enumer- 

 ate as characteristic species of the order: Agrostis rupestris, Potentilla 

 aurea, Sieversia montana, Trifolium alpinum, Gentiana kochiana, 

 Phyteuma hemisphaericuvi, Leontodon pyrenaicus, and other rather 

 widely distributed acidophilous species of the central European 

 mountains. 



Class: — Orders which have numerous, or sociologically important, 

 species in common may be united into "classes. " These usually have a 

 large number of species which are characteristic of the class and are, 

 therefore, ecologically well defined. 



In many cases (but not always) classes may coincide with "plant 

 formations" which have long been physiognomically recognized, such 

 as high moor, swamp, canebrake, heath, forest, dry meadow, and bush 

 steppe. As far as possible they may best be designated by means of 

 these commonly understood terms. 



As a rule, however, it is necessary to give a precise geographic 

 location. For example, the orders of the Molinietalia and Caricetalia 

 fuscae could very well be put into the class of the Eurosibiric flat 

 moors. 



Circle of Vegetation. — The highest unit of a system or classification 

 of vegetation on a floristic basis is the "circle of vegetation." It 

 includes the totality of the communities and species connected with it 

 that are confined, or largely confined, to a natural vegetational region. 



