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Vegetative Survey of Wetland Habitats at Jean Lafitte National Historical Park and Preserve in Southeastern Louisiana
Lauren E. Nolfo-Clements

Southeastern Naturalist, Volume 5, Number 3 (2006): 499–514

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2006 SOUTHEASTERN NATURALIST 5(3):499–514 Vegetative Survey of Wetland Habitats at Jean Lafitte National Historical Park and Preserve in Southeastern Louisiana Lauren E. Nolfo-Clements* Abstract - I conducted a vegetative survey of the wetland habitats at Jean Lafitte National Historical Park and Preserve (JLNHPP) - Barataria Unit. Although wetland habitats make up over 65% of the total park area, there has never been a thorough vegetative survey of this portion of the preserve. Three main habitats were identified: freshwater floating marsh, spoil banks, and waterways. The floating-marsh habitat was further divided into three different community types: thick mat, thin mat, and wax-myrtle thicket. The thick-mat community encompasses four vegetative associations characterized by their dominant species. These are the Sagittaria lancifolia, Typha spp., Schoenoplectus americanus, and Spartina spp. associations. Overall, I identified 168 species in 113 genera in 60 families. Of these, 47 species had never been recorded in the area now encompassed by JLNHPP, and 27 species had not previously been recorded in Jefferson Parish, LA. The three most prevalent families were Cyperaceae (29 species), Poaceae (24 species) and Asteraceae (16 species). Introduction This plant survey was conducted as part of a larger project aimed at characterizing the habitat selection of Myocastor coypus (Molina) (nutria). Since those aquatic mammals are found in nearly all marshy areas of Jean Lafitte National Historical Park and Preserve - Barataria Unit (JLNHPP), an effort was made to become familiar with the wetland plants of the marsh and the surrounding wetland habitats. Additionally, there had never been a vegetative survey aimed at examining the characteristics and discreet plant communities present in the wetlands of JLNHPP. In fact, one of the most startling characteristics of this wetland is the prevalence of freshwater floating marsh. This habitat type, although widespread in the park, has not undergone much scrutiny in the past. Floating marshes are found throughout the world, including in the Danube River delta in Romania, the Amazon Basin in South America, the Netherlands, Australia, Canada, Hawaii, Florida, Georgia, Arkansas, and numerous water bodies in Africa (Sasser et al. 1994). These floating mats of vegetation form on top of peat and muck, three to six meters above subsiding silts and clays deposited by rivers (Chabreck 1988). Sasser and colleagues described the floating marshes of Louisiana (Sasser 1994; Sasser et al. 1994, 1995; Visser et al. 1998, 2000). Although the marshes of JLNHPP resemble *Department of Ecology and Evolutionary Biology, Tulane University, 310 Dinwiddie Hall, New Orleans, LA 70118. Current address - The Humane Society of the United States, Wildlife and Habitat Protection, 700 Professional Drive, Gaithersburg, MD 20879; lclements@hsus.org. 500 Southeastern Naturalist Vol. 5, No. 3 those described in the past, many of the species assemblages found there appear to be unique. Vegetative surveys of the area now encompassed by JLNHPP have been conducted previously, yet these are sparse and often incomplete. Penfound and Hathaway (1938) conducted a survey of plant communities in Louisiana marshes, but did not give exact locations of their study sites. The Bayou Villars transect they describe is roughly located in what is now part of JLNHPP. Therefore, the plant lists and habitat descriptions generated from that 1938 survey are considered comparable to this study. White et al. (1983) conducted a survey of all plant communities of JLNHPP soon after its establishment in 1978. That survey included bottomland hardwood forests, swamps, marshes, canals, and disturbed communities. Yet, a close examination of their list revealed that many of the species characteristic of the floating-marsh habitat are absent, especially those found in association with wax-myrtle thickets and certain thick-mat associations. Conner et al. (1986) published a floristic survey of the known plant species found in the wetlands of the Barataria Basin, LA, an area directly adjacent to JLNHPP. Their list includes species they collected as well as species recorded previously in the literature for that area. That survey encompassed not only fresh-, brackish-, and salt-water marshes, but also bottomland hardwoods, swamps, and disturbed areas. An aspect of the present survey that sets it apart from previous work on the floating marshes of Louisiana and their associated wetland habitats is that careful attention was paid in noting non-native species. Introduced species are present throughout the wetland habitats of JLNHPP. Although some of the non-native species recorded have been established in this area for nearly a century or more, such as Alternanthera philoxeroides (Jipsen 1995) and Eichhornia crassipes (Center et al. 2005), others are relatively new introductions, such as Hydrilla verticillata (Colon-Gaud et al. 2004) and Salvinia minima (Madeira et al. 2003). Additionally, the floating wax-myrtle thicket community, despite its mention in previous works, has hitherto not been described in detail. Moreover, many of the understory species found in the wax-myrtle thickets of the park have not been previously recorded in association with these shrubs. Therefore, the primary focus of this survey was to evaluate the wetland area of JLNHPP for overall species composition and habitat types, while noting the presence of non-native species. Study Site This study was conducted in the Barataria Unit of Jean Lafitte National Historical Park and Preserve, located about 24 km south of New Orleans in Jefferson Parish, LA. The wetland habitats of the park make up about 4900 hectares of the total park area of approximately 7500 hectares (D.P. Muth, JLNHPP, pers. comm.). The climate is subtropical 2006 L.E. Nolfo 501 with annual rainfall exceeding 160 cm and mean annual temperature of 21 °C (summer average of 28.5 °C, winter average of 12.2 °C). The growing season typically exceeds 260 days. The study site is at or slightly below sea level (White et al. 1983). The wetland habitats of the park include three types of floating-marsh, spoil-banks, and open-water habitats. The floating-marsh habitats roughly coincide with types I–V thick- and thin-mat fresh floating marsh, as characterized by Sasser (1994). These habitats are nearly devoid of woody vegetation except for patches of Morella cerifera (Myrica cerifera) distributed across the marsh. Canals that were dug primarily for oil and gas exploration provide access to the marsh. These canals are lined by spoil banks that were constructed from the sediments excavated in the digging of the canals. Woody vegetation dominates this habitat type, in contrast to the herbaceous species that dominate the surrounding canal and marsh communities. Smaller bodies of water that traverse open expanses of marsh are referred to as trenasses, French-Acadian for “trail on the marsh.” These waterways are trappers’ ditches, dug by trappers as routes for laying trap lines (D.P. Muth, JLNHPP, pers. comm.). Trenasses average 2–3 meters wide and are usually completely covered with aquatic vegetation during the growing season. Methods All plant samples were collected either along transects extending up to 450 meters into the open marsh, or from locations within or adjacent to known nutria home ranges. Many specimens were collected along transects during trips conducted solely for the purpose of plant identification. Other specimens were obtained during nutria-radiotracking expeditions or habitatassessment samplings. All mat, wax-myrtle thicket, spoil-bank, and trenasse-waterway collections were carried out on foot. Canal-waterway collections and identifications were done from a 14-foot aluminum flatboat. Specimens were collected May 2003–August 2004. Typically, two to five trips were made to marsh areas almost every week during the warmer months and once a week or less from November to February. Approximately 100 trips were made to the study site. Collections were not made on every trip, but vouchers were taken whenever a fertile specimen was found of a species that was previously unidentified. The location of each specimen was recorded using a Garmin® Etrex Venture GPS unit (Forestry Suppliers, Jackson, MS), and the habitat type and general species habit were noted. Specimens were transported to the Tulane University Herbarium in New Orleans for drying, identification, and cataloging. Species that were previously well known before the study or were not observed in flower or fruit were identified in the field, and no specimens were collected. If such plants could not be identified to species in the field, they are listed by generic name only. Flowering plants were identified using Correll and Johnston (1979), Godfrey and Wooten (1979, 1981), Allen (1992), and Stutzenbaker (1999). 502 Southeastern Naturalist Vol. 5, No. 3 Ferns were identified following Thieret (1980). The native range of each species was noted from the sources above and from the following websites: The International Plant Names Index (www.ipni.org) and the PLANTS National Database (http://www.plants.usda.gov). All scientific nomenclature follows the Integrated Taxonomic Information System (ITIS) online database (www.itis.usda.gov). After being identified, all specimens were given a National Park Service catalog number, entered into their database, and labeled accordingly. All specimens from this survey are on permanent loan to the Tulane University Herbarium from the JLNHPP Herbarium. Results and Discussion A total of 168 species in 113 genera in 60 families were identified (Appendix 1). Of these, 15 species were non-native. The three most prevalent families were Cyperaceae (29 species), Poaceae (24 species), and Asteraceae (16 species). The study area was divisible into three main habitat types: floating marsh, spoil bank, and waterway. The floating marsh was further divided into three distinct community types: thick mat, thin mat, and wax-myrtle thicket. All three communities maintain some buoyancy during the year. The thick-mat community may be further divided into four discreet plant associations characterized by their dominant species. These are the Sagittaria lancifolia, Typha spp., Schoenoplectus americanus, and Spartina spp. associations. The spoil banks are generally of a slightly higher elevation than the surrounding marsh and canals and are made of sediments dredged from the canals. The waterways contain floating mats of vegetation during the growing season, but these differ from those found on the floating marsh in that they are ephemeral and their locations change often with wind and tides. Their species composition also differs from that of the floatingmarsh communities. The following is a description of each of the three habitat types along with a list of the dominant species that characterize each habitat and the discreet communities and associations within these habitats. Floating-marsh habitat This habitat type may be further divided into three distinct plant communities as characterized by their differing species composition and mat thickness. These communities will be referred to as thick-mat, thin-mat, and wax-myrtle thicket floating-marsh communities. Thick-mat community. This floating-marsh community resembles marsh types I-III as described by Sasser et al. (1994), but, at JLNHPP, Panicum hemitomon does not play a major role as it does in the thick-mat types described by Sasser et al. (1994). Panicum hemitomon is primarily found as an understory in certain wax-myrtle thickets and on the edges of thick-mat communities. It does not form widespread monocultures as it does in many other thick-mat floating marshes (Sasser et al. 1996). 2006 L.E. Nolfo 503 At JLNHPP, there are four main associations of thick-mat marsh characterized by their dominant species. The first and most widespread is the Sagittaria lancifolia type, followed by the patchy and nearly monotypic Typha spp., Schoenoplectus americanus, and Spartina spp. types. There are also monospecific patches of Zizaniopsis milaceae and Phragmites australis that are concentrated along marsh edges and waterways. The vines Vigna luteola and Ipomoea sagittata often form dense, twining colonies over small areas of thick-mat vegetation regardless of the dominant species. Sagittaria lancifolia association. The majority of the thick-mat marshes at JLNHPP are dominated by stands of Sagittaria lancifolia acting as an overstory. Leersia hexandra is usually a co-dominant with S. lancifolia in most thick-mat communities. These two species are accompanied by other understory and overstory species whose dominance in the community varies greatly both temporally and spatially. Generally, this association is the most species rich of the four thick-mat associations listed here. Understory species often observed throughout the growing season include Alternanthera philoxeroides, Hydrocotyle spp., Polygonum punctatum, and Phyla lanceolata. Numerous species of Carex and Cyperus are nearly always present in varying stages of flowering, fruiting, or senescence throughout the year. Larger Eleocharis species, especially Eleocharis cellulosa, Eleocharis fallax, and Eleocharis montana are often found as an understory on this type of thick mat. Occassionally, small-scale (1–3 m2), monospecific patches of Juncus spp., Schoenoplectus californicus, and Schoenoplectus tabernaemontani are also common in this community. Various plant species also make ephemeral appearances, primarily in the late summer and fall (August–November). The grasses include Andropogon glomeratus, Echinochloa crusgalli, Echinochloa walteri, several Panicum spp., Paspalum mimus, Paspalum urvillei, Sacciolepis striata, and Setaria spp. Composites also make their appearance on the marsh at this time including Symphyotrichum subulatum, Conoclinium coelestinum, Cirsium horridulum, Eupatorium capillifolium, Iva annua, and Pluchea odorata as do Sesbania spp. and Ludwigia spp. In contrast, the mallows Kosteletzkya virginica and Hibiscus moscheutos ssp. lasiocarpos, in addition to Iris giganticaerulea and Hymenocallis caroliniana, make their debut in the spring and early summer (March–June). Typha spp., Schoenoplectus americanus, and Spartina spp. Associations. As previously mentioned, areas of thick-mat marsh are dominated by Typha spp., Schoenoplectus americanus, and Spartina spp. These thickmat marsh associations are not as widespread as the S. lancifolia-type marsh and often grade into S. lancifolia marsh; some of the understory species listed above are occasionally found on the edges of these monotypic thick-mat associations. This is especially true of the Typha spp. association, which usually has significant overlap with the S. lancifolia marsh and can sometimes act as an overstory. 504 Southeastern Naturalist Vol. 5, No. 3 Thin-mat community. This community corresponds with type IV marsh characterized by Sasser et al. (1994). Generally, thin mat is found on the edges of trenasses or wax-myrtle thickets, or occasionally interspersed with thick-mat habitats. Areas of thin mat that are distributed in a thick-mat matrix may have formed as a result of intense airboat or herbivore activity (L. Nolfo, pers. observ.). Thin-mat marsh is often found under powerlines that are maintained using airboats. Thin mats are also found in areas of intense herbivore activity (primarily nutria, swamp rabbits, and deer) as indicated by scat, resting platforms, and well-worn trails. Generally, thin mats tend to have higher species diversity per 0.5 m2 than do thick mats, averaging 10 species versus 4 or 5 for a thick mat during the peak of the growing season; yet, total above- and below-ground biomass are significantly lower in thin-mat marshes (L. Nolfo, unpubl. data). Ordinarily, small Eleocharis species—especially Eleocharis olivacea, Eleocharis radicans, and Eleocharis vivipara—tend to dominate this community, often in conjunction with Hydrocotyle spp., Bacopa monnieri, Ludwigia repens, and occasionally Micranthemum umbrosum. These species form dense, low carpets from which other, less dominant species emerge. Sagittaria latifolia and Pontedaria cordata are common emergents in this marsh type, as are various species of Cyperus. Habenaria repens is intermittently present, as are Fuirena pumila, Juncus filipendulus, and Ludwigia uruguayensis. Other common thick-mat species found on the thin mat include Alternanthera philoxeroides, Phyla lanceolata, Polygonum punctatum, and Schoenoplectus americanus. On occasion, floating aquatic species usually associated with waterways are found on thin mats. These species sometimes wash in during periods of high wind and tide and may make up a significant portion of the biomass of the thin-mat community on such occasions. Species such as Salvinia minima, Lemna minor, Spirodela polyrhiza, Wolffiela gladiata, and green algae may all be found sporadically on the thin-mat marsh. Wax-myrtle thicket community. Sasser et al. (1994) refer to wax-myrtle thickets as type V floating marshes. Yet, the primary understory they note for these marshes is Panicum hemitomon. Although this grass is present in some patches of Morella (Myrica) cerifera, it is by no means the only, nor the prevalent, understory species in this community at JLNHPP. In fact, the dominant understory in these areas is Sphagnum spp. This moss forms a carpet beneath M. cerifera in most areas that is only broken up by occasional holes in the mat occupied by Lemna minor and Spirodela polyrhiza. Other bryophytes and hepatophytes are often present with the Sphagnum spp., but they generally do not make up a significant portion of the biomass. Thelypteris palustris, Woodwardia areolata, Rhynchospora microcephala, and Decodon verticillatus are the next most common understory species after Sphagnum spp. Clumps of Xyris laxifolia var. iridifolia are also found throughout this floating-marsh community. A number of composites are common, including Eupatorium perfoliatum, Ageratina 2006 L.E. Nolfo 505 altissima, Pluchea foetida, and Solidago fistulosa. Occasionally, areas of Sagittaria lancifolia are also present. Besides the Morella (Myrica) cerifera that makes up the vast majority of the overstory in this community, there is an occasional Triadica (Sapium) sebiferum or, less frequently, Acer rubrum. Spoil-bank habitat Of the habitats investigated, the least time was spent collecting on the spoil banks. Therefore, the species list for this habitat may not be as complete as those for the other habitat types. These thin strips of woody habitat line canals and form a barrier between open water and the marsh in most areas of the park. In some areas, the marsh is directly adjacent to a canal, but this is not usually the case. The dominant overstory species in this habitat is Triadica (Sapium) sebiferum. Other common spoil-bank trees include Salix nigra, Taxodium distichum, Quercus virginiana, Celtis laevigata, and Morella (Myrica) cerifera. Understory species in this habitat that do not occur elsewhere in the park include Colocasia esculenta, various species of Carex, Rhynchospora corniculata, Hymenocallis caroliniana, Arthraxon hispidus, Dichanthelium dichotomum, Phytolacca americana, and many others (see Appendix I). The species included in this habitat are also found in bottomland hardwood forest, and are thus much more tolerant of shade and/or desiccation then are the plants that dominate the floating-marsh and waterway habitats (Denslow and Battaglia 2002). Waterway habitat This habitat type encompasses canals and the trenasses that dissect vast areas of open marsh. Trenasses are filled with floating and submerged aquatic vegetation for the majority of the growing season and tend to revert to open water in the winter months. There is some evidence that these narrow waterways may eventually revert to floating-mat marshes. For example, there are certain trenasses that contain a nearly equal mix of open water species and typical thin-mat species whose roots are still too sparse to walk on. Yet, whether or not these areas are reverting to marsh or becoming open water is unclear. Overall, the species found in canals and trenasses are virtually identical and are thus included in a single habitat type. The types of plants found in the waterways can be divided into three categories according to their habit: floating aquatics, submerged aquatics, and ephemeral-mat species. The two most dominant floating aquatic species in this habitat are Azolla caroliniana and Salvinia minima. Other common floating emergents include Spirodela polyrhiza, Lemna minor, and Heteranthera dubia. Nymphaea odorata is unique in that, although its leaves are emergent, the plant is rooted in the substrate below. The submerged aquatic flora includes Hydrilla verticillata, Vallisneria americana, Myriophyllum aquaticum, Myriophyllum spicatum, Ceratophyllum demersum, Najas guadalupensis, Cabomba caroliniana, and Utricularia spp. 506 Southeastern Naturalist Vol. 5, No. 3 Ephemeral-mat species are plants that form thin, temporary, floating mats in areas that are normally open water. These mats are highly variable both temporally and spatially and are often found floating along the edge of canals and in trenasses. These mats are usually present throughout the summer and early fall, but typically disappear as the growing season ends. Eichhornia crassipes is the dominant mat-forming species and it often persists in waterways through a good portion of the winter months (through January). Some other common ephemeral-mat species include Oxycaryum cubense, Limnobium spongia, Bidens laevis, Alternanthera philoxeroides, Hydrocotyle ranunculoides, Ludwigia peploides, L. uruguayensis, Fuirena pumila, and Pontederia cordata. Forty seven of the species identified in this survey were not recorded for this area by White et al. (1983) or Penfound and Hathaway (1938). A few of these species are common and may constitute a significant portion of wetlands. Most notable among these are Eleocharis fallax, Sphagnum spp., Schoenoplectus americanus, Sagittaria latifolia, Leersia hexandra, Vallisneria americana, Decodon verticillatus, and Oxycaryum cubense. Other species that are widespread but not as prevalent as those listed above include Phyla lanceolata, Xyris laxifolia var. iridifolia, Rhynchospora microcephala, Thelypteris palustris, Cyperus haspan, and Cyperus polystachyos. Twenty nine species that were recorded for this area had not been documented for these types of habitats in Louisiana (see Conner et al. 1986; Penfound and Hathaway 1938; Sasser 1994; Sasser et al. 1994, 1995; Visser et al. 1998, 2000; White et al. 1983). These species include some taxa that are common at JLNHPP, including Woodwardia areolata, Carex frankii, Cyperus haspan, Eleocharis fallax, E. radicans, E. vivipara, Rhynchospora microcephala, and Ludwigia repens, in addition to other, less widespread species. Twenty seven of the species identified were new records for Jefferson Parish, LA across all habitat types (see Penfound and Hathaway 1938; Thomas and Allen 1993, 1996, 1998; White et al. 1983). Nearly half of these new records are from the family Cyperaceae, while the rest belong to a variety of taxa. No new species records for Louisiana were recorded in this survey. Another notable occurrence is the prevalence of introduced species primarily on spoil banks and in waterways. Triadica sebiferum and Eichhornia crassipes have come to dominate each of these habitats and may be considered as noxious invasives on spoil banks and in trenasses, respectively. Salvinia minima, Myriophyllum aquaticum, M. spicatum, and Hydrilla verticillata have all become common in this area. The other non-native species in the marsh habitat, Paspalum urvellei, Pennisetum glaucum, Setaria faberi, Echinochloa crusgalli, Arthraxon hispidus, Colocasia esculenta, Ludwigia uruguayensis, and Lygodium japonicum, appear to be naturalized but not invasive in this area. Alternanthera philoxeroides is found in all wetland habitats of the park and, in some areas, it may constitute a significant proportion of the plant biomass during the growing season. 2006 L.E. Nolfo 507 A few other species expected in wetland habitats were not found at JLNHPP, including Cladium mariscus ssp. jamaicense (Crantz) Kukenth., Pistia stratiotes L., Sagittaria platyphylla (Engelm.) J.G. Sm., Cyperus esculentus L., Carex crus-corvi Shuttlw. ex Kunze, Carex cherokeensis Schwein., Symphyotrichum tenuifolium (L.) Nesom, Scirpus cyperinus (L.) Kunth, Eleocharis albida Torr., Eleocharis baldwinii (Torr.) Chapman, Spartina cynosuroides (L.) Roth, and Osmunda regalis L. These species are commonly found in these types of habitats elsewhere, but are apparently rare or even absent at this site. Acknowledgments I would like to thank the staff of Jean Lafitte National Historical Park and Preserve and the Tulane University Herbarium for the use of equipment and technical support. I would also like to thank Dr. S.P. Darwin and A.S. Bradburn for assistance with identifications and the review of this manuscript. This project was supported by funds from the Coypu Foundation. Literature Cited Allen, C.M. 1992. Grasses of Louisiana, 2nd Edition. Cajun Prairie Habitat Preservation Society, Eunice, LA. Center, T.D., T.K. Van, F.A. Dray, S.J. Franks, M.T. Rebelo, P.D. Pratt, and M.B. Rayamajhi. 2005. Herbivory alters competitve interactions between two invasive aquatic plants. Biological Control 33:173–185. Chabreck, R.H. 1988. Coastal Marshes: Ecology and Wildlife Management. University of Minnesota Press, Minneapolis, MN. Colon-Gaud, J.C., W.E. Kelso, and D.A. Rutherford. 2004. Spatial distribution of macroinvertebrates inhabiting hydrilla and coontail beds in the Atchafalaya Basin, Louisiana. Journal of Aquatic Plant Management 42:85–91. Conner, W.H., C.E. Sasser, and N. Barker. 1986. Floristics of the Barataria Basin wetlands, Louisiana. Castanea 51:111–128. Correll, D.S., and M.C. Johnston. 1979. Manual of the Vascular Plants of Texas. University of Texas at Dallas, Dallas, TX. Denslow, J.S., and L.L. Battaglia. 2002. Stand composition and structure across a changing hydrologic gradient: Jean Lafitte National Park, Louisiana, USA. Wetlands 22:738–752. Godfrey, R.K., and J.W. Wooten. 1979. Aquatic and Wetland Plants of the Southeastern United States: Monocots. University of Georgia Press, Athens, GA. Godfrey, R.K., and J.W. Wooten. 1981. Aquatic and Wetland Plants of the Southeastern United States: Dicots. University of Georgia Press, Athens, GA. Jipsen, W.T. 1995. Annual report: Aquatic plant control operations support center. US Army Corps of Engineers Information Exchange Bulletin 8. USACE. Available online at: www.saj.usace.army.mil/conops/apc/infobulletin/issue8-1.html. Madeira, P.T., C.C. Jacono, P. Tipping, T.K. Van, and T.D. Center. 2003. A genetic survey of Salvinia minima in the southern United States. Aquatic Botany 76:127–139. Penfound, W.T., and E.S. Hathaway. 1938. Plant communities in the marshlands of Southeastern Lousiana. Ecological Monographs 8:3–56. 508 Southeastern Naturalist Vol. 5, No. 3 Sasser, C.E. 1994. Vegetation Dynamics in Relation to Nutrients in Floating Marshes in Louisiana, USA. Coastal Ecology Institute, Center for Coastal, Energy, and Environmental Resources, Louisiana State University, Baton Rouge, LA. Sasser, C.E., E.M. Swenson, D.E. Evers, J.M. Visser, G.O.J. Holm, and J.G. Gosselink. 1994. Floating marshes in the Barataria and Terrebonne Basins, Louisiana. Coastal Ecology Institute, Louisiana State University, Baton Rouge, LA. Report # LSU-CEI-94-02. Sasser, C.E., J.M. Visser, D.E. Evers, and J.G. Gosselink. 1995. The role of environmental variables on interannual variation in species composition and biomass in a subtropical minerotrophic marsh. Canadian Journal of Botany 73:413–424. Sasser, C.E., J.G. Gosselink, E.M. Swenson, C.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. Stutzenbaker, C.D. 1999. Aquatic and Wetland Plants of the Western Gulf Coast. Texas Parks and Wildlife Press, Port Arthur, TX. Thieret, J.W. 1980. Louisiana Ferns and Fern Allies. Lafayette Natural History Museum, Lafayette, LA. Thomas, R.D., and C.M. Allen. 1993. Atlas of the Vascular Flora of Louisiana Volume I: Ferns and Fern Allies, Conifers, and Monocotyledons. Louisiana Department of Wildlife and Fisheries, Baton Rouge, LA. Thomas, R.D., and C.M. Allen. 1996. Atlas of the Vascular Flora of Louisiana Volume II: Dicotyledons Acanthaceae–Euphorbiaceae. Louisiana Department of Wildlife and Fisheries, Baton Rouge, LA. Thomas, R.D., and C.M. Allen. 1998. Atlas of the Vascular Flora of Louisiana Volume III: Dicotyledons Fabaceae–Zygophyllaceae. Louisiana Department of Wildlife and Fisheries, Baton Rouge, LA. Visser, J.M., C.E. Sasser, R.H. Chabreck, and R.G. Linscombe. 1998. Marsh vegetation types of the Mississippi River Deltaic Plain. Estuaries 21:818–828. Visser, J.M., C.E. Sasser, R.H. Chabreck, and R.G. Linscombe. 2000. Marsh vegetation types of the Chenier Plain, Louisiana, USA. Estuaries 23:318–327. White, D.A., S.P. Darwin, and L.B. Thien. 1983. Plants and plant communities of Jean Lafitte National Historical Park, Louisiana. Tulane Studies in Zoology and Botany 24:101–129. 2006 L.E. Nolfo 509 Appendix I (Species Checklist). Below is an annotated species list for the taxa identified during this study. All scientific nomenclature and authorities were checked for accuracy and acceptance according to the Integrated Taxonomic Information System (ITIS) online database at www.itis.usda.gov. Species are listed taxonomically by Division, with the Magnoliophyta being further divided into the classes Liliopsida and Magnoliopsida. Families, genera, and species are listed alphabetically within these taxa. The collection number(s) of each species follows its authority. The numbers listed are the author’s personal collection numbers. Each specimen was also given an official National Park Service catalog number not listed here. An “N” indicates that no specimen was collected for this species because only sterile specimens were found. Non-native species are indicated with an asterisk (*). A pound sign (#) indicates species not previously found in this area by either White et al. (1983) or Penfound and Hathaway (1938). A tilda (~) is indicative of species that have never been recorded in a floating marsh habitat in Louisiana (see Conner et al. 1986; Penfound and Hathaway 1938; Sasser 1994; Sasser et al. 1994, 1995; Visser et al. 1998, 2000; White et al. 1983). An exclamation point (!) precedes new species records for Jefferson Parish, LA across all habitat types. These species were not recorded in this parish by Penfound and Hathaway (1938), White et al. (1983), or Thomas and Allen (1993, 1996, 1998). The habitat(s) and/or community(s) where each plant was found follow the collection number; SB = spoil banks, TK = thick-mat floating marsh, TN = thin-mat floating marsh, WA = waterways, and WM = wax-myrtle thicket floating marsh. For species that are found in more than one habitat or community, the area in which it is most common is listed first, followed by others areas in which it is present but not as prevalent. All specimens were collected by L.E. Nolfo and currently reside in the Tulane University Herbarium. Taxon Collection # Habitat HEPATOPHYTA Marchantiaceae Marchantia spp. N WM BRYOPHYTA Sphagnaceae Sphagnum spp. 173 WM Hypnaceae Hypnum spp. 202 WM PTERIDOPHYTA Azollaceae Azolla caroliniana Willd. 172 WA Blechnaceae ~Woodwardia areolata (L.) T. Moore 174 WM Lygodiaceae *Lygodium japonicum (Thunb.) Sw. 185 SB Salviniaceae *Salvinia minima Baker 171 WA, TN 510 Southeastern Naturalist Vol. 5, No. 3 Taxon Collection # Habitat Thelypteridaceae Thelypteris kunthii (Desv.) Morton 206 SB Thelypteris palustris Schott. 38 WM, TK, TN CONIFEROPHYTA Taxodiaceae Taxodium distichum (L.) L. Rich N SB MAGNOLIOPHYTA Liliopsida Alismataceae #Sagittaria latifolia Willd. N TN, WA Sagittaria lancifolia L. 183 TK, TN, WM Araceae *Colocasia esculenta (L.) Schott N SB Arecaceae Sabal minor (Jacg.) Pers. N SB Bromeliaceae Tillandsia usneoides (L.) L. N SB Commelinaceae Commelina diffusa Burm. F. 126 SB Cyperaceae #Carex alata Torrey 6, 156 TK ~!Carex albolutescens Schwein. 33 TK ~!Carex atlantica Bailey 39 TK Carex comosa Boott. 11, 152 TK, SB ~Carex frankii Kunth 205 SB ~!Carex glaucescens Ell. 150 SB Carex hyalinolepis Steud. 154 SB ~!Carex reniformis (Bailey) Small 144 SB Cyperus erythrorhizos Muhl. 72 TN, TK ~!Cyperus haspan L. 10,37,97,128,135 TN, TK Cyperus odoratus L. 87, 138 TK, TN Cyperus polystachyos Rottb. 48, 69 TK, TN Cyperus virens Michx. 8 TK, TN Eleocharis cellulosa Torr. 43 TK, TN ~!Eleocharis fallax Weath. 158 TK, TN ~!Eleocharis flavescens (Poir.) Urban. 201 TN Eleocharis montana (HBK) R. & S. 24 TK, TN Eleocharis montevidensis Kunth 27 TN Eleocharis olivacea Torr. 68, 198 TN ~!Eleocharis radicans (A. Dietr.) Kunth 52 TN ~!Eleocharis vivipara Link. 200 TN #!Fuirena pumila (Torr.) Spreng. 81, 118, 119 TN, WA #!Oxycaryum cubense (Poppig & Kunth) Lye 127 WA #!Rhynchospora caduca Ell. 167 WM Rhynchospora corniculata (Lam.) Gray 50 SB ~!Rhynchospora microcephala Britt ex Small 80, 146 WM Schoenoplectus americanus Pers. 7 TK Schoenoplectus californicus (C. Meyer) Palla 109 TK Schoenoplectus tabernaemontani (K.C. Gmel.) Palla 9, 54, 55 TK 2006 L.E. Nolfo 511 Taxon Collection # Habitat Hydrocharitaceae *~!Hydrilla verticillata (L.f.) Royle 176 WA Limnobium spongia (Bosc.) L.C. Rich ex Steud. 170 WA ~!Vallisneria americana Michx. 178 WA Iridaceae Iris giganticaerulea Small N TN, TK Juncaceae ~Juncus acuminatus Michx. 155 TK Juncus effusus L. 12, 159 TK, SB ~!Juncus elliottii Chapman 14 TK ~!Juncus filipendulus Buckl. 70 TN #Juncus marginatus Rostk. 164 WM ~!Juncus validus Coville 13 TK Lemnaceae Lemna minor L. N WA, TN Spirodela polyrhiza (L.) Schleiden. 177 WA Wolffia columbiana Karst. N WA ~Wolffiella gladiata (Hegelm.) Hegelm. N WA, TN Liliaceae Hymenocallis caroliniana (L.) Herbert N TK, SB Najadaceae Najas guadalupensis (Spreng.) Magnus N WA Orchidaceae Habenaria repens Nutt. 67 TN Poaceae Andropogon glomeratus (Walt) B.S.P. 131 TK, WM *Arthraxon hispidus (Thunb.) Makino 136 SB ~Dichanthelium dichotomum (L.) Gould 73 SB ~!Dichanthelium spretum (J.A. Schultes) Freckmann 161 SB *Echinochloa crusgalli (L.) Beauv. 56, 64 TK, SB Echinochloa walteri (Pursh) Heller 3, 42 TK, SB #Leersia hexandra Schwartz 4, 32 TK Leersia oryzoides (L.) Sw. N TK Panicum dichotomiflorum Michx. 77, 108, 143 TK Panicum hemitomon J.A. Schultes N TK, WM #Panicum repens L. 106 TK Panicum rigidulum Bosc ex Nees. 96 TK ~!Paspalum minus Fourn. 101 TK *Paspalum urvillei Steud. 53, 71 TK, TN *Pennisetum glaucum (L.) R. Br. 75, 117 SB, TK Phalaris caroliniana Walt. 153 SB, TK Phragmites australis (Cav.) Trin. ex Steud. N TK, SB Saccharum giganteum (Walt.) Pers. 142 TN Sacciolepis striata (L.) Nash 5, 26, 79 TK, TN *~!Setaria faberi Herrm. 113 TK Setaria magna Griseb. 61, 102 TK Spartina patens (Ait.) Muhl. N TK Sphenopholis obtusata (Michx.) Scribn. 162 SB Zizaniopsis miliacea (Michx.) Doell. & Asch. 2, 120 TK 512 Southeastern Naturalist Vol. 5, No. 3 Taxon Collection # Habitat Pontederiaceae *Eichhornia crassipes (Mart.) Solms 22 WA ~!Heteranthera dubia (Jacq.) MacM. 60 WA Pontederia cordata L. 25 TN, WA Typhaceae Typha domingensis Pers. 1, 34, 40, 41 TK Typha latifolia L. N TK Xyridaceae #Xyris laxifolia Mart. var. iridifolia Chapman 139, 186 WM Magnoliopsida Aceraceae Acer negundo L. N SB Acer rubrum L. N SB, WM Amaranthaceae *Alternanthera philoxeroides (Mart.) Griseb. 18 TK, TN, WA, SB Amaranthus australis (Gray) Sauer 59 TK Anacardiaceae Toxicodendron radicans (L.) Kuntze N SB Apiaceae #Hydrocotyle bonariensis Lam. 191 WM Hydrocotyle ranunculoides L.f. 180 WA, SB Hydrocotyle umbellata L. 20 TN, TK Hydrocotyle verticillata Thunb. 35, 44, 181 TN, TK Ptilimnium capillaceum (Michx.) Raf. 16, 163 TK, SB, TN Asteraceae Ageratina altissima (L.) King & H.E. Robins. 145 WM, SB Baccharis halimifolia L. N SB, TK Bidens laevis (L.)BSP 140 WA Cirsium horridulum Michx. N SB, TK Conoclinium coelestinum (L.) DC 125, 133 TK Eclipta prostrata (L.) L. 29 TK, SB Eupatorium capillifolium (Lam.) Small 132 TK, TN, SB Eupatorium perfoliatum L. 93 WM Eupatorium serotinum Michx. 122 SB Iva annua L. 137 TK, SB Mikania scandens (L.)Willd. 91, 111 SB, WM, TK Packera glabella (Poir.) C. Jeffrey 157 TK Pluchea foetida (L.)DC 92, 187 WM Pluchea odorata (L.)Cass. 49 TK ~!Solidago fistulosa Mill. 147 SB, WM Symphyotrichum subulatum (Michx.) Nesom 98, 141, 204 TK, SB Brassicaceae ~!Cardamine parviflora L. 149 TK Cabombaceae Cabomba caroliniana Gray 30 WA Ceratophyllaceae Ceratophyllum demersum L. 175 WA Chenopodiaceae ~Atriplex cristata Humb. & Bonpl. Ex Willd. 88 SB 2006 L.E. Nolfo 513 Taxon Collection # Habitat Clusiaceae Hypericum hypericoides (L.) Crantz 193 WM, TN #!Triadenum virginicum (L.) Raf. 83 WM Convolvulaceae Ipomoea sagittata Poir. 78 TK Ipomoea cordatotriloba Dennst. 107 SB Cucurbitaceae ~Sicyos angulatus L. 104 SB Euphorbiaceae *Triadica sebifera (L.) Small N SB, WM Fabaceae Aeschynomene indica L. 121 TK Gleditsia triacanthos L. N SB #Sesbania drummondii (Rydb.) Cory 89 TK Sesbania herbacea (P. Mill.) McVaugh 63, 90 TK Vigna luteola (Jacq.) Benth. 62 TK Fagaceae Quercus nigra L. N SB Quercus virginiana Mill. N SB Haloragaceae *Myriophyllum aquaticum (Vell.) Verd. N WA *#Myriophyllum spicatum L. 130 WA Hamamelidaceae Liquidambar styraciflua L. N SB Lentibulariaceae Utricularia spp. 182 WA Lythraceae #!Decodon verticillatus (L.) Ell. 203 WM Lythrum lineare L. 51, 197 TK Malvaceae Hibiscus moscheutos ssp. lasiocarpos (Cav.) 169 TK O.J. Blanchard Kosteletzkya virginica (L.) Gray 15 TK Myricaceae Morella cerifera (L.) Small N WM, SB Nymphaeaceae Nymphaea odorata Ait. 36 WA Onagraceae Ludwigia decurrens Walt. 115 TK Ludwigia leptocarpa (Nutt.) Hara 95, 114 TK Ludwigia octovalis (Jacq.) Raven 86 TK #Ludwigia peploides (HBK) Raven 168, 199 WA ~Ludwigia repens Forst. 103, 166 TN *Ludwigia uruguayensis (Camb.) Hara 21 TN, WA Phytolaccaceae Phytolacca americana L. 148 SB Rivina humilis L. 105 SB Polygonaceae Polygonum punctatum Ell. 116 TK, TN, SB 514 Southeastern Naturalist Vol. 5, No. 3 Taxon Collection # Habitat Primulaceae Samolus valerandi ssp. parviflorus (Raf.) Hulten 28, 179 TK, SB Rosaceae Rubus spp. N SB Rubiaceae Cephalanthus occidentalis L. 66 SB Galium tinctorium L. 17, 134 TK, TN Salicaceae Salix nigra Marsh. N SB Saururaceae Saururus cernuus L. 65 TN Scrophulariaceae Bacopa monnieri (L.) Pennell 23, 188 TN #!Micranthemum umbrosum (J.F. Gmel.) Blake 76 TN Ulmaceae Celtis laevigata Willd. N SB #Ulmus alata Michx. N SB Urticaceae Boehmeria cylindrica (L.) Sw. 74, 99 SB Verbenaceae #Phyla lanceolata (Michx.) Greene 19, 31, 184 TK, TN Vitaceae Ampelopsis arborea (L.) Koehne. 124 SB Parthenocissus quinquefolia (L.) Planch. N SB