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M067 Rhynchospora spp. - Eleocharis spp. - Panicum spp. Atlantic & Gulf Coastal Plain Wet Prairie & Marsh Macrogroup

Type Concept Sentence: Common plants of these herbaceous or shrub wetlands include species of Eleocharis, Fimbristylis, Panicum, Rhynchospora, Sarracenia, and Xyris, or shrubs Cephalanthus occidentalis or Vaccinium spp., which occur in warm-temperate Atlantic and Gulf coastal plains depressions and basins, seepage slopes, interdunal swales and poorly drained wet flats.


Common (Translated Scientific) Name: Beaksedge species - Spikerush species - Panicgrass species Atlantic & Gulf Coastal Plain Wet Prairie & Marsh Macrogroup

Colloquial Name: Atlantic & Gulf Coastal Plain Wet Prairie & Marsh

Hierarchy Level:  Macrogroup

Type Concept: Common taxa of these marshes and wet prairies include species of Eleocharis, Fimbristylis, Panicum, Rhynchospora, Sarracenia, and Xyris. Also included are warm-temperate shrub swamps dominated by the shrubs Cephalanthus occidentalis, Vaccinium corymbosum, Vaccinium formosum, or Vaccinium fuscatum. These wetlands occur on the Atlantic and Gulf coastal plains in depressions and basins, seepage slopes, interdunal swales and poorly drained wet flats. The vegetation ranges from floating-leaved aquatics in deeper basins, to emergent marsh in semipermanent water, to drawdown zones with diverse small graminoid and forb vegetation, to shrub swamp and shrub edges. Wet prairie vegetation is also found on extensive wet flats and consists of primarily herbaceous wetland vegetation with relatively thick cover of graminoid species. Examples occupy low, flat plains on poorly drained soils, often saturated for 50-100 days per year. In addition to saturation or flooding, occasional to frequent fires, including during the early growing season, promote the maintenance of this vegetation.

Diagnostic Characteristics: These are herbaceous wetlands, often mixed with low shrubs. They occur in depressions, basins, and interdunal swales, and on seepage slopes, or on wet flats on the coastal plain of the southeastern United States, including some areas as far north as Cape Cod, Massachusetts. Common taxa include species of graminoids Rhynchospora, Panicum, Eleocharis, Aristida, Xyris, forbs Pontederia cordata and Sarracenia and shrubs Hypericum, Vaccinium, Ilex, and Cephalanthus occidentalis.

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: Generally this macrogroup represents warm-temperate vegetation, extending into the cool-temperate zone in New England and with some disjunct occurrences in the Great Lakes area. It includes a wide variety of mainly herbaceous graminoid wetlands, and also some forb and shrub wetlands. Wetland interdune swales are included. Federal land distribution should be updated to include Assateague, Cape Cod, Chincoteague, Fire Island, Plum Island, and maybe others.

Similar NVC Types: No Data Available
note: No Data Available

Physiognomy and Structure: These wetlands are generally dominated by graminoid vegetation. There often are some woody plants, such as low shrubs and/or scattered tall shrubs or very sparse trees present. The tall shrubs have more cover on sites that have not been recently burned. Included here are southern shrublands dominated by Cephalanthus occidentalis or Vaccinium spp.

Floristics: Common taxa include species of Eleocharis, Fimbristylis, Panicum, Rhynchospora, Sarracenia, and Xyris. Graminoids include Andropogon glomeratus, Aristida beyrichiana, Aristida palustris, Aristida stricta, Calamovilfa spp., Carex striata, Ctenium aromaticum, Cyperus haspan, Cyperus virens, Dichanthelium erectifolium, Dichanthelium wrightianum, Eleocharis elongata, Eleocharis equisetoides, Eleocharis microcarpa, Eleocharis quadrangulata, Fuirena scirpoidea, Fuirena squarrosa, Juncus abortivus, Juncus effusus, Juncus repens, Leersia hexandra, Panicum hemitomon, Panicum rigidulum, Panicum verrucosum, Panicum virgatum, Rhynchospora chapmanii, Rhynchospora corniculata, Rhynchospora filifolia, Rhynchospora harperi, Rhynchospora inundata, Rhynchospora tracyi, Saccharum spp., and Steinchisma hians. Forbs include Bartonia verna, Centella erecta, Lachnanthes caroliana, Lachnocaulon minus, Ludwigia glandulosa, Ludwigia linearis, Ludwigia spp., Proserpinaca spp., Rhexia alifanus, Rhexia cubensis, Rhexia spp., Sabatia angularis, Sagittaria longiloba, Sagittaria papillosa, Symphyotrichum subulatum, and Xyris jupicai. Large wetland ferns such as Osmunda cinnamomea and Osmunda regalis also often dominate. Some examples have a very sparse tree component of Magnolia virginiana, Pinus elliottii var. elliottii, Pinus palustris, Pinus serotina, or Taxodium spp. and scattered shrubs, such as Morella cerifera, Morella pensylvanica, Vaccinium corymbosum, or Clethra alnifolia. Other woody plants may include Acer rubrum, Cephalanthus occidentalis, Cyrilla racemiflora, Hypericum chapmanii, Hypericum fasciculatum, Hypericum tenuifolium (= Hypericum reductum), Ilex coriacea, Ilex glabra, Ilex myrtifolia, Lyonia lucida, Nyssa biflora, and Vaccinium spp. Other characteristic and often dominant species for the northern part of the range (Massachusetts to New York or New Jersey) include Cyperus dentatus, Dichanthelium meridionale, Eleocharis acicularis, Eleocharis robbinsii, Eriocaulon aquaticum (= Eriocaulon septangulare), Euthamia caroliniana (= Euthamia tenuifolia), Gratiola aurea, Juncus militaris, Juncus pelocarpus, Lobelia dortmanna, and Xyris difformis. Along rivers in northeastern, central and southern Florida, Cladium mariscus ssp. jamaicense or Panicum hemitomon and Polygonum punctatum were apparently the historical dominant plant species.

Dynamics:  While many of these wetlands are in depressions, slopes and flats, examples which are along rivers are subject to river flooding. The depth, duration and season of flooding are primary influences on the dynamics of this wetland vegetation (Kirkman et al. 2012). Large fluctuations in the water level cause both anaerobic and dry conditions, which promote herbaceous plants rather than trees. Due to these factors and the irregular occurrence of wildland fire during dry conditions, these habitats are maintained as open herbaceous (including some shrub) vegetation. In the humid warm-temperate climatic zone, forests and woodlands are the dominant natural vegetation. Plant species composition (including dominants) may vary seasonally or annually depending on inundation and fire history. Fire may also be necessary to stimulate growth, flowering and seed production of many herbaceous species found in communities of this macrogroup. In the absence of fire, vegetation may become heavily wooded, resulting in the eventual elimination of the herbaceous vegetation (Folkerts 1982).

Environmental Description:  Climate: South of Virginia, the climate is humid, warm-temperate. From eastern Virginia to Cape Cod, Massachusetts, the climate is humid, cool-temperate. Soil/substrate/hydrology: This macrogroup includes non-tidal, freshwater herbaceous marsh, wet prairie, and shrub swamp vegetation. These wetlands occur along rivers and in different types of depressions such as former lake basins, shallow peat-filled valleys, and zones around existing natural lakes (Kushlan 1990). It also includes oligotrophic wetlands maintained by seepage at the zone between an overlaying, permeable sandy layer and a lower layer of relatively impermeable material such as sandstone or clay. This vegetation also includes wetlands of low, flat plains on poorly drained soils, such as Ultisols, Spodosols, Inceptisols, and Entisols (Collins et al. 2001); some of these soils have an argillic horizon which impedes drainage and contributes to high water tables. The low areas where this vegetation occurs on barrier islands and similar immediate coastal areas are dune swales or other basins. These ponds have standing water well into the growing season, and many are permanently saturated. The vegetation also occurs in small basins and depressions, primarily in sandy terrain of the Atlantic Coastal Plain, from southeastern Virginia to Florida, including the Lake Wales Ridge area of central Florida. Most southeastern basins are formed by subsidence of surface sediments caused by solution in underlying limestone, but origins may be different from Delaware northward.

Geographic Range: This macrogroup occurs primarily in the warm-temperate climatic zone on the Atlantic and Gulf coastal plains, including the Mississippi Embayment. It ranges from Massachusetts to Florida and Texas, and also rarely occurs in the Great Lakes region of the United States and Canada (Ontario).

Nations: CA,MX?,US

States/Provinces:  AL, AR?, CT, DC, DE, FL, GA, IN, LA, MA, MD, ME, MI, MS, MXTAM?, NC, NH, NJ, NY, ON, PA?, RI, SC, TX, VA, WI?, WV




Confidence Level: Moderate

Confidence Level Comments: No Data Available

Grank: GNR

Greasons: No Data Available


Concept Lineage: No Data Available

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available

Synonomy: > Bog Swamp (Okefenokee), Prairies (Wharton 1978)
> Deep Fresh-water Marshes (Penfound 1952)
> Depression marshes (Edwards et al. 2013)
> Freshwater Marsh (Kushlan 1990)
> Freshwater marshes (Penfound 1967)
= Graminoid-dominated wetlands (Christensen 2000) [This does not include the shrub swamps which are included with M067.]
> Gulf Coast pitcher plant bog (Folkerts 1982)
? Herb bogs (pitcher plant bogs) (Wharton 1978)
> Interdunal wetlands (Edwards et al. 2013)
> Limesink (Wharton 1978)
> Marsh Ponds (in part) (Wharton 1978)
> Okefenokee Swamp Prairies (Edwards et al. 2013)
> Seepage slope herb bogs (Edwards et al. 2013)
> Shallow Fresh-water Marshes (Penfound 1952)
> Southern Depression Wetlands, open- canopied herbaceous-dominated communities (Kirkman et al. 2012)
> Southern wet meadow (grass-sedge bog) (Penfound 1967)
> grass-sedge savannah (Clewell 1981)

Concept Author(s): Faber-Langendoen et al. (2014)

Author of Description: C.W. Nordman and A.S. Weakley

Acknowledgements: No Data Available

Version Date: 10-15-14

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  • Clewell, A. F. 1981. Natural setting and vegetation of the Florida Panhandle: An account of the environments and plant communities of northern Florida west of the Suwannee River. U.S. Army Corps of Engineers. Mobile, AL. 773 pp.
  • Collins, M. E., R. Garren, and R. J. Kuehl. 2001. Ecological inventory of the Apalachicola National Forest. Summary report submitted to USDA Forest Service. Soil and Water Science Department, University of Florida, Gainesville.
  • Drewa, P. B., W. J. Platt, and E. B. Moser. 2002b. Community structure along elevation gradients in headwater regions of longleaf pine savannas. Plant Ecology 160(1):61-78.
  • Edwards, L., J. Ambrose, and K. Kirkman. 2013. The natural communities of Georgia. University of Georgia Press, Athens, GA. 675 pp.
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