INTRODUCTION 



The National List of Plant Species That Occur in Wetlands 

 (hereafter referred to as the National List ) represents the 

 combined efforts of many biologists over the last decade to define 

 the wetland flora of the United States. The National List has 

 undergone a number of revisions based on intensive review by 

 regional ecologists. National, regional, and State lists are being 

 distributed to provide users with the most current information. 

 We welcome and encourage modification and improvement of the 

 National List . Refinement of the National List will occur 

 continually, reflecting increased knowledge in Indicator 

 assignments, taxonomy, and geographic distribution. We anticipate 

 that further refinement of the National List will lead to 

 additional infra-specific and subregional Indicator assignments. 

 Review documents and procedures are included with the National List 

 to aid and encourage additional review (Appendix A) . 



The U.S. Fish and Wildlife Service initially developed the National 

 List in order to provide an appendix to the Classification of 

 Wetlands and Deepwater Habitats of the United States (Cowardin et 

 al. 1979) to assist in the field identification of wetlands. Plant 

 species that occur in wetlands as used in the National List are 

 defined as species that have demonstrated an ability (presumably 

 because of morphological and/or physiological adaptations and/or 

 reproductive strategies) to achieve maturity and reproduce in an 

 environment where all or portions of the soil within the root zone 

 become, periodically or continuously, saturated or inundated during 

 the growing season (adapted from Huffman 1981). The development 

 of the National List changed significantly when a cooperative 

 review effort was established by the major Federal agencies 

 involved in wetland identification and management. The utility of 

 the National List goes far beyond a simple catalog of wetland 

 plants. The Fish and Wildlife Service, in cooperation with North 

 Carolina State University, has produced a weighted average 

 procedure for using the wetland Indicator assignments of individual 

 species to assist in determining the probability that a community 

 is a wetland (Wentworth and Johnson 1986). This procedure is used 

 by the Soil Conservation Service to aid in the determination of 

 wetlands included under the conservation provisions of the Food 

 Security Act of 1985. The Fish and Wildlife Service, Army Corps 

 of Engineers, Environmental Protection Agency, and Soil 

 Conservation Service use the National List to aid in identifying 

 wetlands falling under their various wetland program 

 responsibilities as specified in the Federal Manual for Identifying 



and Delineating Jurisdictional Wetlands (Federal Interagency 



Committee for Wetland Delineation 1989). 



