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Group Detail Report: G182
Carex interior - Carex lurida - Parnassia grandifolia Seepage Fen Group

The U.S. National
Vegetation Classification
This vegetation of the Ozarks region and Interior Plateau occurs on the sideslopes of hills in narrow valleys, bases of bluffs, rock ledges, and terraces of streams and rivers, where the soil or substrate is saturated by calcareous groundwater seepage. Hydrophytic plants dominate wetter zones with mixed grasses or sedges in intermediate zones and tallgrass prairie species in mesic zones.
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Translated Name:Inland Sedge - Shallow Sedge - Largeleaf Grass-of-Parnassus Seepage Fen Group
Colloquial Name:Central Interior Seepage Fen
The vegetation of this group ranges from the Ozarks region and Interior Plateau as far east as southern Ohio. Examples occur on the sideslopes of hills in narrow valleys, bases of bluffs, rock ledges, and terraces of streams and rivers, where the soil or substrate is saturated by calcareous groundwater seepage. Soils are moist to wet, mucky peat or mineral and are moderately deep to shallow. Some examples contain a thin organic layer over limestone gravel, over a less permeable layer of more solid rock and have exposed bedrock, especially in hanging fens with a slope greater than 35°. The parent material is a mixture of gravel, limestone, and dolomite with fragments of deeply weathered bedrock present, or colluvium over bedrock. Hydrophytic plants dominate the fen, which varies from mixed grass or sedge fen to more tallgrass prairie species mixed with calciphiles. Characteristic herbaceous species include Cardamine bulbosa, Carex interior, Carex leptalea, Carex lurida, Impatiens capensis, Osmunda spp., Parnassia grandifolia, Rudbeckia fulgida var. umbrosa, Scirpus atrovirens, Scirpus cyperinus, Spartina pectinata, and Thelypteris palustris var. pubescens. Mesic prairie grasses include Andropogon gerardii and Sorghastrum nutans. Shrubs such as Alnus serrulata and Salix spp. may occur on some examples of this group. Fires are possible in some of the larger prairie fens.
Small-scale seepage-fed herbaceous wetland with circumneutral soils. Dominated by hydrophytic calciphiles, in particular sedges and graminoids.
Missouri now has a "glacial fen" type that covers northern Missouri and belongs within Midwest Prairie Alkaline Fen Group (G183). Missouri's "prairie fen" is entirely restricted to the Ozarks and belongs within this group. Extension of this group into southern Ohio may need to be confirmed.

Related Type Name:

Short Citation:
  • Evans 1991
  • Faber-Langendoen et al. 2017a
  • Minney 2000
  • Minney pers. comm.
  • Nelson 1985
  • Orzell et al. 1985
  • Richardson and Gibbons 1993
States/Provinces:AR, KY, MO, OH, TN
Range:This group is found within the Interior Plateau region ranging from the Ozarks of Missouri and Arkansas east through Kentucky and Tennessee to southern Ohio.
US Forest Service Ecoregions
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Typical examples of this small-scale group contain a well-developed herbaceous layer dominated by hydrophytic graminoid and sedge species. Some examples, especially those ranging into the eastern portions of the Interior Highlands, may contain a sparse to somewhat dense cover of shrubs 1-2 m tall. Trees are uncommon in these wetlands, although Acer rubrum may invade some examples.
Primarily calciphilic species of sedges (Carex spp.) and graminoids such as Andropogon gerardii and Sorghastrum nutans dominate examples of this group. Other characteristic species include Cardamine bulbosa, Carex interior, Carex leptalea, Carex lurida, Impatiens capensis, Osmunda spp., Parnassia grandifolia, Rudbeckia fulgida var. umbrosa, Scirpus atrovirens, Scirpus cyperinus, Spartina pectinata, and Thelypteris palustris var. pubescens. Tall shrub such as Alnus serrulata, Cornus amomum, and Salix spp. may occur. Acer rubrum can invade examples of this group.
Stands occur in patches on the sideslopes of hills in narrow valleys, bases of bluffs, rock ledges, and terraces, where the soil or substrate is saturated by calcareous groundwater seepage. Soils are mucky peat or mineral, with pH above 6.5, and shallow (0-100 cm), depending on natural disturbance and slope. The parent material is a mixture of gravel and dolomite with fragments of deeply weathered bedrock present. Some examples contain gravelly alluvium or colluvium over dolomite bedrock. The bedrock strata are often exposed, especially in hanging fens where the slope is greater than 35°.
The primary environmental characteristic of stands of this group is the consistent presence of seepage flow. It is assumed that the vegetation would be affected by long-term drought cycles, but this has not been documented. The recruitment of tree and shrub seedlings will be limited by soil wetness to drier embedded microsites, thereby making canopy gaps persist longer than in adjacent forests, and creating and sustaining the openings in which this vegetation occurs. Fires may penetrate from adjacent forests, but only in the driest conditions are they likely to be intense enough to have much effect. Seeps are fairly permanent features of the landscape, but may potentially be created, destroyed, or altered in extent because of changes in groundwater flow, stream entrenchment or headward erosion, mass movement on slopes, or long-term climatic cycles. Examples are often left undisturbed when surrounding forests are logged. The effects of logging on water infiltration or surface flow may have significant indirect effects on the integrity of examples.
S. Menard and M. Pyne      Version Date: 19May2015

  • Evans, M. 1991. Kentucky ecological communities. Draft report to the Kentucky Nature Preserves Commission. 19 pp.
  • Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2017a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
  • Minney, D. 2000. Edge of Appalachia Preserve: Plant community descriptions. Preliminary draft. An unpublished report for the Ohio Chapter of The Nature Conservancy.
  • Minney, D. Personal communication. The Nature Conservancy, Ohio Chapter, Dublin.
  • Nelson, P. W. 1985. The terrestrial natural communities of Missouri. Missouri Natural Areas Committee, Jefferson City. 197 pp. Revised edition, 1987.
  • Orzell, S., B. Pell, and G. Tucker. 1985. Notes on three palustrine natural community types in the Arkansas Ozarks. Arkansas Academy of Science Proceedings 39:141-143.
  • Richardson, C. J., and J. W. Gibbons. 1993. Pocosins, Carolina bays, and mountain bogs. Pages 257-310 in: W. H. Martin, S. G. Boyce, and A. C. Echternacht, editors. Biodiversity of the southeastern United States: Lowland terrestrial communities. John Wiley and Sons, Inc., New York.

USNVC Credits: Detailed Description of the National Vegetation Classification Types

Date Accessed:

To cite a description:
Author(s). publicationYear. Description Title [last revised revisionDate]. United States National Vegetation Classification. Federal Geographic Data Committee, Washington, D.C.

About spatial standards:
The United States Federal Geographic Data Committee (hereafter called the FGDC) is tasked to develop geospatial data standards that will enable sharing of spatial data among producers and users and support the growing National Spatial Data Infrastructure (NSDI), acting under the Office of Management Budget (OMB) Circular A-16 (OMB 1990, 2000) and Executive Order #12906 (Clinton 1994) as amended by Executive Order #13286 (Bush 2003). FGDC subcommittees and working groups, in consultation and cooperation with state, local, tribal, private, academic, and international communities, develop standards for the content, quality, and transferability of geospatial data. FGDC standards are developed through a structured process, integrated with one another to the extent possible, supportable by the current vendor community (but are independent of specific technologies), and publicly available.

About this document
This document contains type descriptions at the Group level of the U.S. National Vegetation Classification. These descriptions were primarily written by NatureServe ecologists in collaboration with Federal Geographic Data Committee Vegetation Subcommittee and a wide variety of state, federal and private partners as a part of the implementation of the National Vegetation Classification. Formation descriptions were written by the Hierarchy Revisions Working Group. The descriptions are based on consultation with natural resource professionals, published literature, and other vegetation classification systems. The Ecological Society of America's Panel on Vegetation Classification is responsible for managing the review and formal adoption of these types into the National Vegetation Classification. Partners involved in the implementation of the USNVC include:

U.S. Government
  • Department of Agriculture (USDA)
  • Department of Commerce (DOC)
  • Department of Defense (DOD)
  • Department of the Interior (USDI)
  • Forest Service (FS) - Chair
  • National Agriculture Statistical Service (NASS)
  • Natural Resources Conservation Service (NRCS)
  • National Oceanic and Atmospheric Administration (NOAA)
  • National Marine Fisheries Service (NMFS)
  • U.S. Army Corps of Engineers (USACE)
  • U.S. Navy (NAVY)
  • Bureau of Land Management (BLM)
  • Fish and Wildlife Service (FWS)
  • National Park Service (NPS)
  • U.S. Geological Survey (USGS)
  • Environmental Protection Agency (EPA)
  • National Aeronautics and Space Administration (NASA)
Non U.S. Government
  • NatureServe (NS)
  • Ecological Society of America (ESA)

Given the dynamic nature of the standard, it is possible a type description is incomplete or in revision at the time of download; therefore, users of the data should track the date of access and read the revisions section of the website to understand the current status of the classification. While USNVC data have undergone substantial review prior to posting, it is possible that some errors or inaccuracies have remained undetected.

For information on the process used to develop these descriptions see:

Faber-Langendoen, D., T. Keeler-Wolf, D. Meidinger, D. Tart, B. Hoagland, C. Josse, G. Navarro, S. Ponomarenko, J.-P. Saucier, A. Weakley, P. Comer. 2014. EcoVeg: A new approach to vegetation description and classification. Ecological Monographs 84:533-561 (erratum 85:473).

Franklin, S., D. Faber-Langendoen, M. Jennings, T. Keeler-Wolf, O. Loucks, A. McKerrow, R.K. Peet, and D. Roberts. 2012. Building the United States National Vegetation Classification. Annali di Botanica 2: 1-9.

Jennings, M. D., D. Faber-Langendoen, O. L. Louckes, R. K. Peet, and D. Roberts. 2009. Standards for associations and alliances of the U.S. National Vegetation Classification. Ecological Monographs 79(2):173-199.

FGDC [Federal Geographic Data Committee]. 2008. Vegetation Classification Standard, FGDC-STD-005, Version 2. Washington, DC., USA. []

For additional information contact:

  • Implementation of the U.S. National Vegetation Classification Standard - Alexa McKerrow (
  • NatureServe's Development of NVC Type Descriptions - Don Faber-Langendoen (don_faber-
  • Ecological Society of America's Review of the Type Descriptions
  • Federal Geographic Data Committee - Vegetation Subcommittee's Activities - Marianne Burke (