ADAPTATIONS AND DISTRIBUTION 



Soils in Oklahoma arc incoinjilctclv known. Sullicicnt information has 

 been gathered to indicate several broadly different basic types; those based 

 upon (1) weathered sandstone outcrops; (2) weathered limestone; and (3) 

 clay deposited in ancient Iresh water or marine basins. Smaller areas of other 

 types exist, such as the alluvial loams and clay-sands on the flood plains of 

 streams, and the sand dunes and salt plains which occur in the West. 



Ecologically, the state is sometimes thought of as essentially prairie; but 

 this is at best only a half truth. Most of the eastern half is wooded, with oaks 

 and hickories dominant, either as scrubby thickets or as savannah. Bottom 

 lands along the streams, except in the western portion of the state, have a 

 forest of mixed deciduous woods; cottonwood, elm, willows, and redbud 

 being particularly noticeable. Rather extensive patches of pine woodland 

 occur locally on the Ouachita Mountains of the Southeast; and on the flood 

 plain of the Red River and its major tributaries in this region, such southern 

 trees as sweet-gum and cypress are common. The western half of the state 

 is grassland, broken here and there by islands of oak-hickory woodland, and 

 oak-shinnery, in addition to which are the flood-plain forests of the rivers 

 and, in the west central part, the wooded ravines. In the Northwest, fairly 

 extensive stands of sagebrush occur. Climatically, one would expect the true 

 prairie (i.e., Andropogon or tall-grass prairie) to extend over much of the 

 eastern half. Actually, except for "islands" of it farther south, only a rela- 

 tively small tongue enters the Northeast from Kansas. This distribution is 

 traceable primarily to the fact that soil type determines the present vegetative 

 cover as much as climate does over most of Oklahoma. In general, limestone 

 and clay soils favor climax grassland; and sandstone soils, sub-climax wood- 

 land or savannah in much of the state. This is the reason why larger or 

 smaller islands of prairie in woodland and islands of oak-hickory woodland 

 in prairie are so often encountered (for further detail of ecological relations 

 see Bruner, 1931, and Bragg and Smith, 1943). 



In fauna, Oklahoma varies greatly from east to west, less so from north 

 to south. This might be expected inasmuch as the extreme southeastern 

 corner is little more than a northward extension of the Gulf Coastal Plain 

 whereas Black Mesa at the northwestern edge of the Panhandle is an eastern 

 outlier of the Rocky Mountain Highland. Conditions of existence vary 

 enormously from east to west and many components of the eastern, mesically 

 adapted fauna and flora find their western limits in Oklahoma. Likewise, 

 many of the western and southwestern, xerically adapted forms meet an 

 ecological barrier here to further extension to the eastward. In short, no state 

 of the United States except Texas offers more favorable opportunities to learn 

 just what happens when two differently adapted faunas or floras meet. 



Since Amphibia are dependent upon factors correlated with available 

 moisture, both in their individual lives and in breeding, these factors are em- 

 phasized, especially among the salientians. Morphological variations might 

 be expected within species and between species as conditions become grad- 

 ually less favorable for any given group, west to east or east to west, the de- 

 gree of variation dependent upon the interplay of genetic factors tending 



