Print Report

CEGL004665 Panicum hemitomon Marsh

Type Concept Sentence: No Data Available

Common (Translated Scientific) Name: Maidencane Marsh

Colloquial Name: Deltaic & Chenier Plains Maidencane Marsh

Hierarchy Level:  Association

Type Concept: This association is a very common fresh marsh type of the Chenier and Deltaic plains of Louisiana and the upper coast of Texas. This type is broadly defined to include several manifestations related to geographic location, associated vegetation, and degree of subsidence. However, all examples are strongly dominated by Panicum hemitomon. Much of the variability currently reflected in this type is exhibited between examples found in the Chenier and Deltaic plains. The Deltaic Plain expressions are largely floating marsh ("thick mat flotant"), while very little flotant is present in the Chenier Plain. Commonly occurring species in the Chenier Plain of Louisiana include Sagittaria lancifolia, Eleocharis spp., Typha spp., Cladium mariscus ssp. jamaicense, Ludwigia spp., Schoenoplectus californicus, Crinum americanum, Zizaniopsis miliacea, and Cephalanthus occidentalis, while in the Deltaic Plain common associates include Leersia oryzoides, and sometimes Sagittaria lancifolia, along with Thelypteris palustris, Osmunda regalis, Vigna luteola, Ipomoea sagittata, Polygonum sagittatum, and Conoclinium coelestinum.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This association (CEGL004665) was merged with former CEGL007892, assuming the latter''s name, Panicum hemitomon Semipermanently Flooded Herbaceous Vegetation. This type is broadly defined to include several manifestations related to geographic location and the associated vegetation and degree of subsidence. Marshes located further inland are less influenced by the current deltaic processes and may reflect a condition of this association prior to deltaic subsidence and subsequent flotant formation. Arguably, the Chenier Plain type should be classified as distinct from the Deltaic Plain type based on associated species and functional differences (flotant vs. not). Inclusional patches of Morella cerifera-dominated shrubland (~Morella cerifera - Panicum hemitomon Floating Marsh (CEGL007834)$$) up to many acres in size are common in the Deltaic Plain. Visser and Sasser (1998) did not recognize a "Flotant Marsh Shrubland." The Cajun name for Panicum hemitomon is "Paille Fine," pronounced "pie feen." Note: This CEGL004665 is placed in a seasonally flooded formation even though the element name reflects that it is semipermanently flooded. More information is needed to better separate the fresh to oligohaline marshes along the coast of Louisiana into associations. This vegetation may be floating and non-floating and share many species [see Similar Associations]. These marshes appear to undergo seasonal shifts in vegetation composition. In addition, subsidence, sea-level rise, and hydrologic changes are likely causing shifts in species composition, adding to the difficulty in classifying this vegetation.

Similar NVC Types: No Data Available
note: No Data Available
Physiognomy and Structure: No Data Available

Floristics: Species richness in this flotant marsh type is relatively high. All examples are strongly dominated by Panicum hemitomon. Commonly occurring species in the Chenier Plain of Louisiana include Sagittaria lancifolia, Eleocharis spp., Typha spp., Cladium mariscus ssp. jamaicense (= Cladium jamaicense), Ludwigia spp., Schoenoplectus californicus (= Scirpus californicus), Crinum americanum, Zizaniopsis miliacea, and Cephalanthus occidentalis, while in the Deltaic Plain common associates include Leersia oryzoides, and sometimes Sagittaria lancifolia, along with Thelypteris palustris, Osmunda regalis, Vigna luteola, Ipomoea sagittata, Polygonum sagittatum, and Conoclinium coelestinum (= Eupatorium coelestinum) (Sasser et al. 1996). Of interest, a few species more commonly associated with acidic, moist to wet pine flatwood communities are found in some flotant examples of the Deltaic Plain, including Asclepias rubra, Calopogon tuberosus, Platanthera nivea (= Habenaria nivea), Pteroglossaspis ecristata, Osmunda cinnamomea, Osmunda regalis, and Xyris caroliniana (Sasser et al. 1996). This association also includes localized freshwater marshes north of Lake Pontchartrain in Louisiana dominated by Panicum hemitomon and Orontium aquaticum. These marshes are surrounded by Taxodium spp. forests, and widely scattered Taxodium ascendens occurs in these examples. These marshes, located further inland, are less influenced by the current deltaic processes and may reflect a condition of this association prior to deltaic subsidence and subsequent flotant formation. In Texas, other components of flotant marsh dominated by Panicum hemitomon include Eleocharis quadrangulata, Erechtites hieraciifolius, Galium tinctorium, Habenaria repens, Hydrocotyle verticillata, Leersia hexandra, Sacciolepis striata, and Thalia dealbata. Invasive species noted in this community include Ludwigia grandiflora (= Ludwigia uruguayensis).

Dynamics:  Many of these mashes are maintained in herbaceous condition by burning in the fall, when unburned they develop a shrub layer of Morella cerifera. This shrub community may revert to herbaceous condition after the shrub layer develops enough mass to weigh down the floating mat causing submergence and eventual shrub mortality (Sasser et al. 1996). Localized examples of his association, north of Lake Pontchartrain in Louisiana dominated by Panicum hemitomon and Orontium aquaticum, are surrounded by Taxodium spp. forests, and widely scattered Taxodium ascendens occurs in these examples. These marshes, located further inland, are less influenced by the current deltaic processes and may reflect a condition of this association prior to deltaic subsidence and subsequent flotant formation.
Environmental Description:  This fresh marsh type occurs in the Chenier and Deltaic plains of Louisiana and the upper coast of Texas, as well as in localized areas north of Lake Pontchartrain. These more inland marshes are less influenced by the current deltaic processes and may reflect a condition of this association prior to deltaic subsidence and subsequent flotant formation.
Geographic Range: This association is restricted to Louisiana and Texas.

Nations: US

States/Provinces:  LA, TX


Confidence Level: Low

Confidence Level Comments: No Data Available
Grank: G3G4

Greasons: No Data Available
Type Name Database Code Classification Code
Class 2 Shrub & Herb Vegetation Class C02 2
Subclass 2.C Shrub & Herb Wetland Subclass S44 2.C
Formation 2.C.4 Temperate to Polar Freshwater Marsh, Wet Meadow & Shrubland Formation F013 2.C.4
Division 2.C.4.Ne Atlantic & Gulf Coastal Marsh, Wet Meadow & Shrubland Division D322 2.C.4.Ne
Macrogroup 2.C.4.Ne.1 Annual Wild Rice - Saltmeadow Cordgrass - Pickerelweed Fresh-Oligohaline Tidal Marsh Macrogroup M066 2.C.4.Ne.1
Group 2.C.4.Ne.1.b <i>Zizaniopsis milacea - Spartina patens - Panicum hemotimon</i> Freshwater Tidal Marsh Group G913 2.C.4.Ne.1.b
Alliance A3578 Maidencane Floating Marsh Alliance A3578 2.C.4.Ne.1.b
Association CEGL004665 Maidencane Marsh CEGL004665 2.C.4.Ne.1.b
Concept Lineage: duplicate record

Predecessors: No Data Available

Obsolete Names: No Data Available

Obsolete Parents: No Data Available
Synonomy: = Panicum thick mat marshes (Sasser et al. 1996)
Concept Author(s): L.M. Smith

Author of Description: R.E. Evans and J. Teague

Acknowledgements: No Data Available

Version Date: 07-29-02
  • Couvillion, B. R., J. A. Barras, G. D. Steyer, W. Sleavin, M. Fischer, H. Beck, N. Trahan, B. Griffin, and D. Heckman. 2011. Land area change in coastal Louisiana from 1932 to 2010. U.S. Geological Survey Scientific Investigations Map 3164, scale 1:265,000. 12 pp. pamphlet.
  • Couvillion, B. R., and H. Beck. 2013. Marsh collapse thresholds for coastal Louisiana estimated using elevation and vegetation index data. Journal of Coastal Research, Special Issue 63:58-67.
  • Deegan L. A., H. M. Kennedy, and C. Neill. 1984. Natural factors and human modifications contributing to marsh loss in Louisiana''s Mississippi River deltaic plain. Environmental Management 8(6):519-528.
  • Glick, P., J. Clough, A. Polaczyk, B. Couvillion, and B. Nunley. 2013. Potential effects of sea-level rise on coastal wetlands in southeastern Louisiana. Journal of Coastal Research, Special Issue 63:211-233.
  • Howard R. J., and I. A. Mendelssohn. 1999. Salinity as a constraint on growth of oligohaline marsh macrophytes. I. Species variation in stress tolerance. American Journal of Botany 86(6):785-794.
  • LNHP [Louisiana Natural Heritage Program]. 2009. Natural communities of Louisiana. Louisiana Natural Heritage Program, Louisiana Department of Wildlife & Fisheries, Baton Rouge. 46 pp. [http://www.wlf.louisiana.gov/sites/default/files/pdf/page_wildlife/6776-Rare%20Natural%20Communities/LA_NAT_COM.pdf]
  • NPS [National Park Service]. 2005. Jean Lafitte NHP 2005 Habitat Data Map (1:12,000) created by USGS-NWRC. Unpublished data shared by NPS.
  • Neubauer, S. C. 2013. Ecosystem responses of a tidal freshwater marsh experiencing saltwater intrusion and altered hydrology. Estuaries and Coasts 36:491-507.
  • Sasser, C. E., J. G. Gosselink, E. M. Swenson, M. Swarzenski, and N. C. Leibowitz. 1996. Vegetation, substrate and hydrology in floating marshes in the Mississippi River delta plain wetlands, USA. Vegetatio 122:129-142.
  • Southeastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Durham, NC.
  • USGS [U.S. Geological Survey]. 2013b. Trends and causes of historical wetland loss in coastal Louisiana. Fact Sheet 2013-3017. U.S. Geological Survey. March 2013
  • Visser, J. M., and C. E. Sasser. 1998. 1997 Coastal vegetation analysis. Unpublished report to Greg Steyer, Louisiana Department of Natural Resources, Baton Rouge, LA. Draft report November 20, 1998. 47 pp.
  • Williams, S. J. 2013. Sea-level rise implications for coastal regions. Journal of Coastal Research, Special Issue 63:184-196. [http://tidesandcurrents.noaa.gov/sltrends/msltrendstable.htm]
  • Willis, J. M., and M. W. Hester. 2004. Interactive effects of salinity, flooding, and soil type on Panicum hemitomon. Wetlands 24(1):43-50.