Theodore Roosevelt National Park
The primary objective of the first year of the project was to determine the number and distribution of exotic plant species within the park. A preliminary list of exotics was provided by park personal. A more complete list of exotics found in the park was then generated using Heidel's (1990) list of "Preliminary Vascular Flora of Theodore Roosevelt National Park". The origin of all of the plant species listed in that report were determined from Stevens (1963) and Flora of the Great Plains (Great Plains Association 1986).
Butler, Jack L. and Einhellig, Frank A.
"Exotic Plants in Theodore Roosevelt National Park,"
University of Wyoming National Park Service Research Center Annual Report: Vol. 15
, Article 41.
Available at: http://repository.uwyo.edu/uwnpsrc_reports/vol15/iss1/41