CHAPTER VIII 



GRASSLAND FORMATIONS OF THE 

 COLD TEMPERATE BELTS 



I. General Oecology of Grassland. Meadow and steppe. Protective measures in 

 meadows against winter drought. Hygrophilous character during the vegetative season. 

 Xerophilous structure of steppe-plants. 2. The Vegetation in Meadow Districts 

 and Steppe Districts, i. Meadow. Meadow in Europe. Meadow in Eastern Asiatic 

 parkland and in North America, ii. Steppe. Western part of the North American 

 prairie. The prairie in Kansas according to Hitchcock ; in Nebraska according to Pound 

 and Clements. The steppe in the Black Sea district according to Rehmann. The high- 

 steppe near Alexandrovsk according to Gruner. 



i. GENERAL OECOLOGY OF GRASSLAND. 



The grassland formation is represented in the cold temperate belts by 

 meadow and steppe only ; savannah, which still occasionally occurs in 

 mild-winter zones, is absent, for the grassland climate of the higher latitudes 

 possesses in the severe winter cold, usually accompanied by wind, a factor 

 hostile to trees. 



Between meadow and steppe a line cannot yet be drawn with certainty 

 in all cases, and an exposition of the oecology of grassland is greatly needed. 

 Moreover, the character of meadow or steppe depends to a great extent not 

 only on climate but also on soil, and shows rapid change in undulating 

 tracts, inasmuch as the higher places are occupied by xerophilous, and 

 the lower ones by tropophilous or hygrophilous vegetation ; and the 

 designation of the one type as climatic, and of the other as edaphic, is 

 in such a case quite arbitrary. 



Whether the meadow of cold-winter belts is to be included among 

 tropophilous or among hygrophilous formations cannot at present be 

 decided with any certainty. A closer investigation into the protection 

 afforded against drought during winter will probably enable us to come 

 to a decision. Meanwhile, it appears to me that some phenomena may 

 be considered as xerophilous devices to protect meadow-plants against 

 the desiccating effects of winter cold and wind, in particular the circum- 

 stance that the higher projecting parts perish at the conclusion of the vege- 

 tative season, and that the meadow can therefore be completely covered 

 with snow. During winter, as in very dry weather, the stomata are closed ; 

 and the chemical changes that take place in leaves at the commencement 

 of the cold ma)- perhaps be connected with protection against drought. 

 Apparently they do not occur in submerged plants. In any case, there 

 is far less danger from drought during winter to the meadow than to 



