Plant Communities of the World 281 



and Koeleria cristata. Similar communities are found in locally 

 dry continental areas in middle Europe, as in the Wallis of 

 Switzerland; a fine Festucetum vallesiacae, and related unities, 

 are found similarly in the Bohemian foothills and in the Jugo- 

 slavian Velebit Mountains. The most famous communities of 

 this class are the prairies and great plains of America, so well 

 studied by Clements, Shantz, Livingston and Shreve, Weaver 

 and Fitzpatrick, and others, that I need not go into details. 



The decided continentality of the Duriherbosan climate must 

 rely on the strong change of dry and wet without great tempera- 

 ture differences. The areas with rich savannah grasslands cover 

 wide stretches in Brazil, the Argentine, Australia, and especially 

 in Africa. With increasing coldness, the communities merge 

 toward steppe prairie, and where the climate becomes less 

 hostile to trees one finds gradual transitions to Hiemilignosa. 



75. Sempervirentiherbosa: Evergreen grassland (meadows). — 

 The turgor for the most part suffices to keep the dominant 

 grasses and herbs in their shape, and mechanical stififening is 

 therefore slight. These meadows have no pronounced winter 

 rest; they sprout whenever temperature permits. They prevail 

 in a cool oceanic climate poleward beyond the tree limit, in the 

 mountains above the tree limit, edaphically in flood areas of 

 sea and rivers and on windy coasts. Most meadows, all middle 

 European meadows of the plains, are biotically conditioned 

 (half-culture) and would turn into forests if left alone. Many 

 leaves die in winter, but younger ones in all stages are always 

 present and new ones are formed. The plant is evergreen, but 

 the single leaf is not. Whenever I dug in the Engadine in the 

 cold months when the temperature of the air was far below 

 zero, I found the local habitat under the heavy snow cover to 

 be around zero and the vegetation green, always ready to 



