1020] PALMER, LIGNEOUS FLORA OF THE STAKED PLAINS 103 



ami 



for entering the new territory, and these may be long delayed, thus allowing 



species 



igraphical position and ecol 



canyons certain woody plants are as conspicuous for their absence as others 

 are surprising by their presence. Possibly a more extensive and thorough 

 exploration than I was able to make might discover some of the plants men- 

 tioned below, but in a careful though brief examination of some of the most 

 typical and heavily wooded portions of the Paloduro Canyon I found no 

 trace of them. Conditions in the River-bank zone of the canyon appear to 

 be ideal for the growth of the Mexican or Riverside Walnut {Juglans rupes- 

 tris), which is such a common and characteristic tree along all the streams 

 of the Edwards Plateau, and which approaches the Staked Plains at least as 

 near as Sweetwater, Texas, and extends northward into the Wichita Moun- 

 tains of Oklahoma; but it does not appear to have as yet found means of 

 entering the canyon. The Pecan, too, should thrive and easily maintain 

 itself along the river banks were it once introduced, and it would have no 

 very wide distance to bridge from the upper Pease River, in Hardiman 

 County, Texas, where it was observed growing spontaneously. It is also 

 surprising that only one species of Oak has found its way into the canyons, 

 since several shrubby and arborescent forms occur not far to the south and 

 east. The American Elm and Red Mulberry might both be expected in 



the 



the 



olorado not far to the southeast. No species of Red 

 Haws, R°oses, Blackberries, Viburnums, Dogwood, Ash nor many other 

 plants that might naturally be expected were seen. 



The entire absence of many plant families and the poor representation of 

 others which are largely developed in the surrounding country and some of 

 which seem well adapted to conditions here, together with the miscellane- 

 ous character of the plants that have become established are all strongly 

 suggestive of the extremely new and incomplete status of the flora. There 

 are, too, so far as known, no endemic species and a general absence of well- 

 marked varieties such as would naturally have been developed had many of 

 the species been long isolated under the peculiar conditions obtaining in the 

 canyons from the parent stock and normal habitat. 



All this is in striking contrast to the peculiar canyon flora of the Edwards 

 Plateau, where more or less modified representatives of a typical eastern 

 flora occupy certain restricted areas. If the former may be compared to 

 remnants of aboriginal tribes surviving in isolated fastnesses amidst an alien 

 and conquering race, the assemblage of plants in the Paloduro pnd other 

 canyons of the Staked Plains may better be likened to the heterogeneous 

 society in process of formation and adjustment drawn from many sources 

 to a newly opened land. Here, in fact, are found many of the phenomena 

 of a flora in the making, and one that has not yet reached a state of even 

 nnnroximate eouilibrium or attained a well-balanced and permanent form. 



