520 



NATURALIST'S GUIDE TO THE AMERICAS 



prairie) of the eastern and southern 

 portions. Includes rolling hills, mostly 

 low, but rising to an extreme height 

 of 100 ft. or more and originally 

 covered with a dense sod, the grass 

 cover reaching a height of one to 3 ft., 

 and with broad valleys through which 

 meandered creeks and rivers both for- 

 merly with sandy or gravelly beds, 

 fringed with timber and shrubbery. 

 Characterized by grass communities in 

 which blue-stems (Andropogon), prai- 

 rie-grasses (Koeleria) and spear-grasses 

 (Siipa) are prominent. Conspicuous 

 habitats, aside from the prairie itself, 

 are the sand-bedded larger streams with 

 shallow shifting channels and sand- 

 bars; and the smaller creeks with their 

 now-muddy banks and fringe of timber 

 and thicket, which may run back into 

 the draws; prairie sloughs, ponds and 

 marshes, with here and there mud flats, 

 sometimes alkaline; weed patches and 

 plum thickets ; and the artificial features 

 created by cultivation. 



3. The sand-hill region, an area of 

 18,000 sq. mi., in the central portion, to 

 which may be added 2000 sq. mi. in out- 

 lying smaller tracts. A very rough 

 area with hills rising 200 ft. or more. 

 Characterized by bunch-grass communi- 

 ties with Redfieldia, Calamovilfa, certain 

 blue-stems, and black grama (Bouteloua 

 hirsuta) the dominant grasses. Yucca is 

 a conspicuous plant and there are some 

 cacti. Conspicuous habitats: the open 

 sand-hills, mostly fixed and with a 

 grassy cover, but here and there with 

 ' 'blow-outs" and shifting areas of sand; 

 a little shrubbery in the pockets in the 

 hills, with an occasional hackberry or 

 hackberry thickets; wet valleys, with 

 hay flats, sloughs, marshes or lakes, the 

 latter with sandy, marshy, or boggy 

 shores; and with willow thickets, tree 

 claims, and groves around the ranches. 

 There are few streams and these around 

 the eastern margin, soon entering 

 tongues of prairie which follow back 

 into the hills. 



4. The plains region including the 

 western portions of the state and 

 extending eastward along the north- 



ern boundary and, to a less degree, 

 along the southern. Characterized by 

 short-grass communities, dominated by 

 grama grass, buffalo-grass, and certain 

 grass-like sedges, and with straggling 

 western yellow pines (Pinus scopulorum) 

 scattered over the canyon sides, the 

 buttes, ridges and talus slopes. Con- 

 spicuous habitats: the broad slightly 

 uneven, grassy plains; streams running 

 generally in canyons, frequently deep 

 and rock-walled; also dry "sand-draw" 

 canyons carrying water only after rain 

 or from melting snow; irrigating ponds 

 and ditches, rarely with small marshy 

 tracts; rocky escarpments, ridges and 

 buttes with scattering pines; deciduous 

 trees and shrubbery in the bottoms of 

 the canyons, along the streams, or about 

 the ranches; and an increasing amount 

 of cultivated land. 



5. The coniferous woodland region, 

 including the Pine ridge in the north- 

 western part of the state and smaller 

 areas south and east of it, where, on the 

 walls and talus slopes of extensive 

 canyons, rising sometimes to a height of 

 500 or 600 ft., a coniferous woodland has 

 developed. Conspicuous habitats: the 

 pine-clad slopes; deciduous timber and 

 shrubbery at the bottom of the canyons; 

 with springs and cool, clear brooks, and 

 occasional small ponds and marshes, 

 due to the work of beavers. 



To these might be added the bad lands, 

 due to excessive erosion, which, because 

 they exist as small scattered areas, we 

 have preferred to reckon as a habitat 

 in the plains region, characterized by 

 their sparse flora and fauna, restricted 

 to only those forms which can with- 

 stand the severe conditions. 



The boundaries between these areas 

 were more sharply defined before the 

 state was settled, cultivation having 

 tended to obliterate them. In the maj or 

 areas the vegetation has been but 

 little changed, but the disappearance of 

 the prairie sloughs and marshes and the 

 other changes due to the settling up of 

 the state have led to the disappearance 

 of many animals, especially among the 

 higher vertebrates. 



