594 ZONES AND REGIONS [Pt. Ill, Sect. II 



originally covered with forests, and that these were destroyed by Indians 

 in order to produce grassy tracts for the buffaloes. Reliable grounds for this 

 opinion have, however, not yet been supplied. Indeed it will hardly be 

 possible to solve the question with certainty. 



ii. STEPPE. 



Steppe districts have at least in certain localities preserved their original 

 physiognomy to a greater extent than most meadow districts, for they are 

 less densely inhabited by man and present greater difficulties than do 

 meadow districts to being brought under cultivation. For example, the 

 tvestem part of the North American prairie (Figs. ^i y 333)> m Dakota, 

 Nebraska, Kansas, and Texas, is certainly an original steppe, however much 

 it may have been modified recently, and its xerophilous character increases 

 from east to west, so that on the Missouri river it passes over into meadow, 

 and at the foot of the Rocky Mountains into desert. 



Hitchcock 1 has given a vivid description of the dry, western steppe in the 

 State of Kansas. The prairie is more extensive than all the other formations 

 together. The western half of the State lies in the district known as 

 ' Great Plains,' which extends westwards to the Rocky Mountains, south- 

 wards to Texas, and northwards to a great distance. The land in this 

 district is nearly flat, but here and there interrupted by river-beds : — 



' One may ride for many miles without seeing any distinguishable eminence to 

 interrupt the uniformity of the plain, which extends to the horizon in all directions. 

 There are no trees, no shrubs (although many plants are lignified at the base), no tall 

 herbs. . . .' 



The following plants are characteristic of the western plain : Erysimum asperum, 

 Polygala alba, Malvastrum coccineum, Linum rigidum, Sophora tomentosa, Psoralea 

 tenuiflora (Leguminosae), Cereus viridiflorus (SW. Kansas), Opuntia Rafinesquii, 

 O. missouriensis, O. fragilis, Gutierrezia Euthamiae (Compositae), Aplopappus spinu- 

 losus (Compositae), Evax prolifera (Compositae), Engelmannia pinnatifida (Com- 

 positae), Thelesperma gracile (Compositae), Artemisia Wrightii, Senecio Douglasii, 

 Cnicus ochrocentrus, Asclepias Jamesii, Krynitzkia crassisepala (Boraginaceae), 

 Ipomoea leptophylla, Solanum triflorum, Chamaesaracha sordida (Solanaceae), Ver- 

 bena bipinnatifida, Cladothrix lanuginosa (Amarantaceae), Chenopodium olidum, 

 C. Fremonti incanum, Allium Nuttallii, Aristida purpurea, Munroa squarrosa (Fig. 

 337), Elymus Sitanion. The following extend further to the east : Kuhnia eupa- 

 torioides (Compositae), Liatris punctata (Compositae), Solidago missouriensis, Am- 

 brosia psilostachya, Lepachys columnaris (Compositae), Echinospermum Redowskii 

 occidentale (Boraginaceae), Evolvulus argenteus, Solanum rostratum, Oxybaphus 

 angustifolius (Nyctaginaceae), Andropogon furcatus, A. scoparius, Chrysopogon 

 nutans (these three grasses predominate in the eastern prairies), Schedonnardus 

 texanus (Gramineae), Bouteloua oligostachya (Gramineae), B. racemosa, Buchloe 

 dactyloides (Gramineae, Fig. 336), Koeleria cristata, Eatonia obtusata (Gramineae). 



1 Hitchcock, op. cit., p. 62. 



