Invalid Unit Specified
G188 Pontederia cordata - Panicum hemitomon River & Basin Freshwater Marsh Group

The U.S. National
Vegetation Classification
Type Concept Sentence: These are non-tidal freshwater marshes dominated by emergent graminoid, floating-leaved aquatic vegetation, or shrubs. The dominant species may vary, but Pontederia cordata and Panicum hemitomon are typical. These are found on coastal plains from Massachusetts to Louisiana and Texas along rivers or in the headwaters of rivers, and in depressions, including karst depressions.
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Common (Translated Scientific) Name: Pickerelweed - Maidencane River & Basin Freshwater Marsh Group
Colloquial Name: Atlantic & Gulf Coastal Plain River & Basin Freshwater Marsh
Hierarchy Level: Group
Type Concept: These are non-tidal freshwater marshes dominated by emergent graminoid vegetation, floating-leaved aquatic vegetation, or shrubs. They occur on the coastal plains from Massachusetts to Louisiana and Texas. These marshes are most extensive in Florida along rivers or in the headwaters of rivers, and in karst depressions. The vegetation mosaic includes a range of mostly herbaceous wetland plant communities that may be referred to as marshes, meadows and prairies. The dominant species may vary, but Pontederia cordata and Panicum hemitomon are typical. Along rivers in Florida, Cladium mariscus ssp. jamaicense or Panicum hemitomon and Polygonum punctatum were apparently the historical dominant plant species, but a variety of other species may also be present. In the deeper water of karst depressions, common plants include Typha latifolia, Pontederia cordata, Nelumbo lutea, and others. In areas with less flooding, Panicum hemitomon, Leersia hexandra, and other species may be found. Plant species composition (including dominants) may vary seasonally or annually depending on inundation and fire history (especially in Florida).
Diagnostic Characteristics: These are non-tidal freshwater marshes dominated by emergent graminoid, floating-leaved aquatic vegetation, or shrubs. The dominant species may vary, but Pontederia cordata and Panicum hemitomon are typical. These are found on the coastal plains along rivers or in the headwaters of rivers, and in depressions, including karst depressions.
Rationale for Nominal Species or Physiognomic Features: This group consists of vegetation which has many different dominant plants. The species Pontederia cordata and Panicum hemitomon are nominal plants because they are limited to marshes and are common in the vegetation of this group.
Classification Comments: The floristic differences between these non-tidal coastal plain graminoid freshwater marshes and other eastern North American marshes may be minor; separation is better defined as warm-temperate or cold-temperate freshwater marshes. This group is the warm-temperate graminoid freshwater marsh.
Similar NVC Types:
G125 Eastern North American Freshwater Marsh, note:
G129 South Florida Freshwater Marsh & Wet Prairie, note:
G557 Southeastern Ruderal Marsh, Wet Meadow & Shrubland, note:
G777 Atlantic & Gulf Coastal Interdunal Marsh & Prairie, note:
Physiognomy and Structure: These long-hydroperiod herbaceous wetlands include floating-leaved aquatic vegetation in the areas with the longest duration of flooding, and emergent graminoid vegetation in areas that usually dry out for some period of time in the growing season. In Florida, the extensive graminoid marsh areas may be prone to wildland fire, and in absence of disturbances may become shrub-dominated. The role of hurricanes is probably important in reducing the cover of tall shrubs and trees and promoting the anaerobic conditions that restrict the survival of upland plants.
Floristics: Diverse assemblages of vegetation, ranging from open-water communities to emergent and graminoid marshes and scattered shrublands occur in these marshes. Along rivers in Florida, Cladium mariscus ssp. jamaicense or Panicum hemitomon and Polygonum punctatum were apparently the historical dominant plant species, but a variety of other species may also be present. In marshes along rivers outside of Florida, typical species include Zizaniopsis miliacea, Zizania aquatica, and Pontederia cordata. Sandbars along coastal plain rivers may be dominated by Panicum rigidulum, Polygonum hydropiperoides, and Polygonum punctatum. Marsh areas in large depressions with approximately a meter of standing water tend to support dense stands of emergent herbaceous perennials, often in stands dominated by one species. Species include Typha latifolia, Pontederia cordata, Nelumbo lutea, and others. Where there is less water (usually present only during the wet season), more graminoid vegetation is present, with species such as Panicum hemitomon, Leersia hexandra, and others.
Dynamics: Examples which are along rivers are subject to river flooding. Plant species composition (including dominants) may vary seasonally or annually depending on inundation and fire history. In the absence of fire, portions of stands may become dominated by Salix caroliniana. Then they may succeed to Acer rubrum until a replacement fire or mechanical activity restores the marsh. The marshes in large karst depressions are subject to long-term changes in hydroperiods in addition to the typical year-to-year fluctuations. The lakes in central Florida can become dry in a short time, as has happened at Paynes Prairie where water levels have fluctuated greatly over time (Patton and Judd 1986).
Environmental Description: Climate: Humid, warm temperate. Soil/substrate/hydrology: This group occupies non-tidal, generally narrow, but widely fluctuating, zones of freshwater herbaceous marsh vegetation along rivers and in different types of large depressions such as former lake basins, shallow peat-filled valleys, and zones around existing natural lakes (Kushlan 1990). Included here are streamside marshes (such as in the New Jersey Pine Barrens) and graminoid vegetation on sandbars of coastal plain rivers. The rivers in Florida where it extensively occurs include the Myakka, St. Johns, Kissimmee, and perhaps Caloosahatchee rivers. The hydroperiod is generally longer than 180 days, 7 to 12 months (Kushlan 1990). Outside of Florida, this vegetation mostly occurs in smaller areas.
Geographic Range: This group is most extensive in the Florida peninsula, but occurs elsewhere in the coastal plain, from Massachusetts to Louisiana and Texas, and in limited interior areas, in Kentucky, Tennessee and West Virginia.
Nations: US
States/Provinces: AL, CT, DE, FL, GA, KY, LA, MA, MD, MS, NC, NH?, NJ, NY, PA?, RI, SC, TN, TX, VA, WV
US Forest Service Ecoregions (2007)
Domain Name:
Division Name:
Province Name: Southeastern Mixed Forest Province
Province Code: 231    Occurrence Status: Possible
Section Name: Southern Atlantic Coastal Plains and Flatwoods Section
Section Code: 232J     Occurrence Status: Possible
Omernik Ecoregions: 65:C, 65o:C, 75:C, 75a:C, 75b:C, 75c:C, 75d:C, 75f:C, 75l:C, 76:C, 76c:C
Plot Analysis Summary:
Confidence Level: Moderate
Confidence Level Comments:
Grank: GNR
Greasons:
Concept Lineage:
Predecessors:
Obsolete Names:
Obsolete Parents:
Synonomy: < Basin Marsh (FNAI 1990)
< Floodplain Marsh (FNAI 1990)
< Freshwater Marsh (Kushlan 1990)
Concept Author(s): J.A. Kushlan (1990)
Author of Description: C.W. Nordman
Acknowledgements:
Version Date: 13May2015
References:
  • 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]
  • FNAI [Florida Natural Areas Inventory]. 1990. Guide to the natural communities of Florida. Florida Natural Areas Inventory and Florida Department of Natural Resources, Tallahassee. 111 pp.
  • Huffman, J. M., and W. S. Judd. 1998. Vascular flora of Myakka River State Park, Sarasota and Manatee counties, Florida. Castanea 63:25-50.
  • Kushlan, J. A. 1990. Freshwater marshes. Pages 324-363 in: R. L. Myers and J. J. Ewel, editors. Ecosystems of Florida. University of Central Florida Press, Orlando.
  • Patton, J. E., and W. S. Judd. 1986. Vascular flora of Paynes Prairie Basin and Alachua Sink Hammock, Alachua County, Florida. Castanea 51:88-110.