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 flf Wetlands and Deeowater 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. Wetland identification manuals which incorporate the National 

 List have recently been produced by the Corps of Engineers (Environmental 

 Laboratory 1987) and the U.S. Environmental Protection Agency (Sipple 1988). 



