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On June 1, 2012 there will be a new National Wetland Plant List. The May 9, 2012 Federal Register includes a notice that the final National Wetland Plan List has been published and will go into effect June 1, 2012. This is the first time the National Wetland Plant List (NWPL) has been successfully revised since 1988. Its represents the culmination of a multi-year effort led by the U.S. Army Corp of Engineers in coordination with the U.S. Fish and Wildlife Service, the U.S. Environmental Protection Agency and the U.S. Department of Agriculture. It replaces the 1988 National List of Plant Species that Occur in Wetlands.
This was not a small effort. There were 6700 plants in the 1988 plant list. The new list includes 8200. The majority of the increase in numbers is due not to the addition of new wetland plants, but the ongoing reorganization of plants worldwide. Since the original wetland plant list was created in 1988 analysis of DNA species relationships has led to many changes in the classifications of individual plants. Many plants have been moved to different genera or families. Sometimes an individual genus has been divided up.
Wetland plants are divided into broad categories. Obligate plants (OBL) always occur in standing water or saturated soils. Facultative plants (FAC) are found in wet to dry soils—but mostly wet soils. Facultative upland plants (FACU) occur rarely in wetland soils. The majority of plants found in the U.S. do not fall into any of these categories. They are upland plants (UPL) that almost never occur in water or saturated soils.
This means there is a kind of plant continuum. There are some plants with very specific needs with respect to how wet (OBL) or dry (UPL) the soil is and those that 
can adapt (FAC and FACU). Revising the plant list was the opportunity to incorporate new knowledge about where plants live and simultaneously update the nomenclature to keep up with the plant DNA research.
Will the new plant list have a big change on what areas are identified as a wetland?
First, keep in mind, wetland vegetation is one of the three criteria used to identify a wetland: vegetation, soils and hydrology.
It would depend on how many plants changed classification. Only 12% of the plants on the list did change – and they were equally divided between those moved to a less wet category ( i.e., FAC to FACU) and those moved to a more wet designation (i.e. FACU to FAC).
Wetland delineators need to acquaint themselves with the new list and start using it June 1. It is fortunate that the U.S. Army Corps of Engineers put a lot of work into developing a user-friendly resource. As of this writing, the NWPL database is still the one that was posted for reviewing and updating the list. Anyone accessing it has to pass through warnings about site security which is symptomatic of the list’s location on a Department of Defense webserver. However sometime early in June that will change. The address will remain the same, but the server will be changed. The plant list itself will be easier to access and use. For example right now it is possible to enter a county or location and get a list of all wetland plants associated with that area. Therevised website will include the ability to draw a circle on a map and get a list of 
wetland plants that could occur within that boundary. Later in the year the rest of the plants found in North America (both Canada and the U.S) will be added to the database—increasing the list to 32,000. These will provide a comprehensive database with all the current (as well as past names), links to pictures, geographic extent, etc. for all the plants found in North America.
But that’s not all. In late summer the Corps expects to add an electronic key to support accurate identification of wetland plants. The first step will be to enter the geographic location where the plant was found and then additional information to identify the plant species.
Finally it will not be necessary to wait another 25 years to update the plant list. The new list can be continually revised. There is a process in place to change a plant’s status. It is necessary to provide information to explain why the change is proposed that may need to be supported by field work to confirm that the proposal to make a change is scientifically grounded.
Corps Press Release: http://www.usace.army.mil/Media/NewsReleases/tabid/203/Article/1185/updated-2012-national-wetland-plant-list-is-available.aspx
National Wetland Plant List Federal Register Notice: http://www.gpo.gov/fdsys/pkg/FR-2012-05-09/pdf/2012-11176.pdf
The National Wetland Plant List: http://wetland_plants.usace.army.mil
Wetland Definitions and Classifications in the United States: http://water.usgs.gov/nwsum/WSP2425/definitions.html
Why do those plant names keep changing http://www.cnpsci.org/html/PlantInfo/WhyPlantNamesChange.htm
Development of Plant Taxonomy
http://herbarium.usu.edu/teaching/4420/History.htm
