71 



parently of Rocky Mountain derivation, such as Woodsia 

 scopulina, Eriogonum Alleni, and Senecio antennariij 'olins , whose 

 ancestors, Wherry (10) suggests, may have migrated eastward 

 across northern North America and made their way southward 

 along the Appalachians in pre-glacial times. 



Finally, there should be mentioned, of course, the hundreds 

 of weeds, introduced from Europe and elsewhere in the last 

 three centuries, which have come to be the dominant species of 

 clearings and waste grounds. 



Literature 



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3. Kearney, T. H. The Lower Austral element in the flora of the Southern 



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4. Merriam, C. H. Life Zones and Crop Zones of the United States. Bull. 



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5. Millspaugh, C. F. The living flora of West Virginia. W. Va. Geol. Surv. 



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