Coastal Plain Vascular Plant Endemics: Phytogeographic Patterns Bruce A. Sorrie; Alan S. Weakley Castanea, Vol. 66, No. 1/2, Southeastern Endemics: Speciation and Biogeography: University of North Carolina at Wilmington. April 15, 1999. (Mar. - Jun., 2001), pp. 50-82. Stable URL: http://links.jstor.org/sici?sici=0008-7475%28200103%2F06%2966%3A1%2F2%3C50%3ACPVPEP%3E2.0.CO%3B2-B Castanea is currently published by Southern Appalachian Botanical Society.
Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/journals/sabs.html. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission.
The JSTOR Archive is a trusted digital repository providing for long-term preservation and access to leading academic journals and scholarly literature from around the world. The Archive is supported by libraries, scholarly societies, publishers, and foundations. It is an initiative of JSTOR, a not-for-profit organization with a mission to help the scholarly community take advantage of advances in technology. For more information regarding JSTOR, please contact
[email protected].
http://www.jstor.org Tue Jan 15 16:39:20 2008
CASTANEA 66(1-2): 50-82. MARCWJUNE 2001
Coastal Plain Vascular Plant Endemics:
Phytogeographic Patterns
BRUCE A. SORRIE~ and ALAN S. WEAKLEY~ '3076 Niagara-Carthage Road, Whispering Pines, North Carolina 28327;
2Association for Biodiversity Information, The Nature Conservancy, 6114 Fayetteville Road, Suite 109,
Durham, North Carolina 27713
ABSTRACT Papers on the phytogeography of the North American coastal plain are poorly represented in the botanical literature, despite the fact that the coastal plain is one of the continent's major floristic provinces. Some authors have discussed plant distribution andlor endemism for local regions, but none have treated the coastal plain a s a whole. We synthesized data from many sources and have compiled lists of all endemic families, genera, species, and infraspecific taxa. Analysis of these lists, and of county-level range maps, yields recurring patterns of species distributions. We define and map 27 such patterns and list representative taxa for each. The boundaries of many of these patterns appear to circumscribe centers of endemism. We discuss underlying reasons for the high diversity and endemism in the coastal plain, as well as the geographical derivation of the endemics, the age of the flora, and the role of past geological events.
INTRODUCTION Background In this paper we describe and delimit the major kinds of geographical distribution that vascular plant taxa exhibit on the North American coastal plain. The paper is a natural outgrowth of 1)having produced a complete list of plant taxa endemic to the coastal plain (Sorrie and Weakley, in prep.) and 2) having prepared approximately 1000 county-level range maps for rare or restricted plant taxa. It soon became evident to us that these taxa fall into a number of discrete geographical areas or patterns. Rare or uncommon endemics are useful for phytogeographical analyses because they reflect the distribution patterns of common species, yet they can also be used to recognize more local or regional patterns of distribution. In addition, an analysis of the distribution of endemics can be used to help understand patterns of evolutionary divergence, especially a t the generic level, in unrelated groups, and help direct research efforts of conservationists and evolutionary biologists. Papers on the phytogeography of the North American coastal plain region as a whole are poorly represented in the botanical literature. Gleason and Cronquist (1964), Takhtajan (1986) and Thorne (1993) have written overviews of the continental phytogeography, in which they define and discuss the Atlantic and Gulf Coastal Plain Floristic Province. These authors point out the fact that endemism is high, including "several endemic genera" and "several hundred endemic species." However, their discussions are hampered by the lack of specific data regarding these estimates. Braun (1955) discussed the floristic relationship between the coastal plain and Appalachian upland plants, based on past geological events and climate change. Other phytogeographers have discussed the general distribution, range limits, and migration routes of selected coastal plain taxa (Bozeman 1971; Bridges and Orzell 1989; Fernald 1918, 1931, 1937; Hardin and White 1989; Huck et al. 1989; Jackson and Singer 1998; Keddy 1981; LeBlond 2001; McLaughlin 1932; Peattie 1922; Reznicek 1994; Roland and Smith 1969; Svenson 1941) but none of them describe more than a few patterns of distribution. Harper 50
CASTANEA VOLUME 66
(1907) was the first to describe centers of endemism within the coastal plain. He identified six major centers of distribution, although we now recognize several times that number. It must be remembered that Harper was one of the pioneer botanists in the South and had little herbarium material to work with, despite the fact that he worked well into the twentieth century. The seminal works of Neil1 (1957) and James (1961) on the Florida endemics related plant distributions to historical geology and provided a framework for more far-reaching studies on the endemics of the coastal plain. Bozeman (1971) discussed five patterns of endemism in xeric forest and scrub communities of the southeastern coastal plain; all of them are included in the present paper. Moreno-Casasola (1988) examined the distributions of dune plants of the Mexican Gulf Coast. She identified seven patterns and then related them to other floristic regions. One of her patterns clearly defines the southern limit of the North American coastal plain; the rest have their affinities with the Caribbean region or are pan-tropical. Very recently, Ricketts et al. (1999) and Stein, Kutner, and Adams (2000) presented various estimates of biodiversity of North America and the United States, respectively. Geographical data in these works are based on relatively small ecoregions and neither publication treats floristic provinces per se. To date, there are no modern papers treating the phytogeographic patterns or centers of endemism of the whole coastal plain. One major problem that has hampered floristic botanists and phytogeographers in the past is the limited number of specimens collected from the southeastern states (Duncan 1953). Today, with an ever-growing body of herbarium specimens, as well as the burgeoning databases of Natural Heritage Programs, the ranges of southern plants (especially rare or uncommon taxa) are much better known. Floras andlor atlases are now available or are being produced in nearly every southern state from Virginia to Texas and Arkansas (Chester et al. 1993-97; Harvill et al. 1992; Hatch, Gandhi, and Brown 1990; Jones and Coile 1988; Smith 1988; Taylor and Taylor 1994; Thomas and Allen 1993-98; Townsend 1999; Weakley 2000; Wunderlin 1998; Wunderlin, Hansen, and Bridges 1996). Unfortunately, as habitats have been lost and natural areas converted, it becomes increasingly difficult to know whether a n isolated plant population reflects reality or is a by-product of habitat loss. Alternatively, apparent disjunctions may simply reflect incomplete inventory efforts.
Definition of Coastal Plain The area covered by this paper is the Atlantic Coastal Plain and the Gulf Coastal Plain of North America, as described by Fenneman (19381, Hunt (1974), and Walker and Coleman (1987). Figure 1 depicts this area, which extends from southeastern Massachusetts south to the Florida Keys, west to eastern Texas, and southward to Tamaulipas, Mexico. A significant projection, termed the Mississippi Embayment, extends northward to southern Illinois. We treat the entire Mississippi Embayment as part of the coastal plain. A significant number of coastal plain plants have been documented from the southwesternmost counties of Nova Scotia. Although not geologically part of the coastal plain, we include this phytogeographically important area in this work. The area of the Coastal Plain Floristic Province is approximately 1,166,000 krn2 (450,193 mi.2),excluding the submerged continental shelf (Walker and Coleman 1987). The coastal plain covers about 8% of the North American landmass. The coastal plain represents the exposed portion of the continental shelf. It is composed of sedimentary deposits of Cretaceous age or younger (Fenneman 1938, Walker and Coleman 1987). The inland boundary is a geologically distinct and often botanically sharp zone a t the interface of the Cretaceous deposits and older, Paleozoic formations. In most of the Atlantic Coastal Plain, this boundary is called the fall-line and corresponds to the interface of the relatively flat coastal plain and the topographically varied, usually rocky piedmont. The term fallline is not used west of central Alabama, because a t that point the true piedmont disappears; the Cretaceous-Paleozoic boundary turns northwestward and the coastal plain directly abuts montane and plateau physiographic provinces. The Gulf Coastal Plain is divided into eastern and western sectors by the Mississippi Embayment. MARCWJUNE 2001
51
Figure 1. Atlantic and Gulf Coastal Plains of North America. The inland boundary marks the junction of Cretaceous deposits and older Paleozoic formations.
The Atlantic and Gulf Coastal Plain Floristic Province Not only does the coastal plain reflect a distinct geology, it also is nearly conterminous with a unique floristic province. A floristic province is a geographic division of the globe in which large numbers of plant species (and usually some genera) share the same distribution. Such taxa are restricted, or nearly so, to that area and create a relatively uniform and distinctive flora. These endemic and near-endemic taxa have all adapted to a suite of specific edaphic and climatic conditions and are said to be characteristic of that province and are not shared with other floristic provinces (Takhtajan 1986). Gleason and Cronquist (1964) and Takhtajan (1986) apply the name Atlantic and Gulf Coastal Plain Floristic Province to this distinct assemblage of plants and plant communities of the North American coastal plain. Takhtajan (1986) considers the coastal plain to be the most sharply defined of any of the North American floristic provinces, in part because of its close adherance to the boundary of the geologic coastal plain and also because of the relatively uniform, acidic, soil types. In the Atlantic Coastal Plain and East Gulf Coastal Plain, the delineation between this floristic province and the adjacent Appalachian Floristic Province is relatively straightforward. To be sure, many taxa common to both provinces are widespread in each, but the majority display geographic separation. A relatively small number of coastal plain endemics occur in specialized habitats in the piedmont and mountains. A larger number of piedmont/montane taxa spill over onto the coastal plain. In the West Gulf Coastal Plain, the delineation is less clear. This is particularly true of the boundary between the southern Great Plains and the coastal plain. In southeastern Texas, the transition zone is very broad (Diamond and Smeins 1985); there, significant numbers of taxa from the North American Prairies Province and from the Sonoran Province occur on the geologic coastal plain. As reflected in our map of the coastal plain (Figure I), we consider the northwesternmost of these Texas prairies to be part of the 52
CASTANEA VOLUME 66
Prairie Province, but retain the others in our discussion of the coastal plain because of their occurrence on Cretaceous or younger deposits. The South Texas Plains are similarly problematic. There, large numbers of species from the adjacent Sonoran Floristic Province occur on the geologic coastal plain, along with plants that clearly have been derived from the Coastal Plain Floristic Province. Southward, towards the Rio Grande River and well into Tamaulipas, Mexico, the prominance of mesquite (Prosopis glandulosa) has given rise to a regional vegetation type called mesquital (Crosswhite 1980). Throughout the region, coastal plain taxa increase in importance as one travels eastward. This transitional area harbors a large number of endemic taxa, yet its phytogeographic importance has been largely overlooked. For these reasons we include it in our analyses. South Florida also is included in this paper, even though we recognize that this area is part of the West Indian Floristic Province. First, subtropical Florida is part of the geologic coastal plain and we wish to be consistent with our thinking regarding southern Texasmamaulipas. Second, we believe it important to include all of the North American coastal plain. Third, the large number of south Florida endemic taxa makes an important contribution to North American biodiversity and underscores the fact that despite close proximity to Cuba and the Bahamas, the south Floridian biota has experienced its own evolutionary pathway. Definition of Endemic Our main criterion for inclusion as endemic is that a t least 90% of documented occurrences of each taxon must lie within the Atlantic and Gulf Coastal Plains. This figure allows us to include taxa which clearly are coastal plain in distribution, but which may overlap slightly in adjacent floristic provinces or which may have disjunct occurrences in other floristic provinces. Such taxa may be termed near-endemics. Although the great majority of plants included herein are strict endemics, a significant number have been documented as disjuncts far removed from the coastal plain. Discovery of these disjuncts is ongoing and continues to intrigue botanists and phytogeographers. Taxa with well-known disjunct populations in Nova Scotia, the western Great Lakes region, northwestern Virginia, and in the Highland Rim and Cumberland Plateau of central Tennessee and eastern Kentucky are included. A number of less well-known disjuncts have been found in specialized inland habitats in the New York-New England region, southwestern North Carolina, northwestern Georgia, northeastern Alabama, northern Arkansas, southern Missouri, and in the Edwards Plateau of Texas. We also include taxa that are localized and presumably rare disjuncts in the Caribbean islands (primarily western Cuba and the northwestern Bahama Islands) andlor to mainland Central America. In all cases, taxa must pass our 90% criterion. Our knowledge of the Caribbean ranges of these taxa is far from complete; further collecting will uncover new disjunct taxa and reveal that other taxa are too widespread to include on our list. However, unless such taxa are proved to be widespread in the Caribbean, we will continue to view them as essentially endemic to the Atlantic and Gulf Coastal Plains. METHODS Source Material We have drawn distributional data freely from a wide variety of sources, including regional, state and local floras, floristic atlases, journal papers, monographs, Natural Heritage Program databases, our own field work, and direct examination of herbarium specimens. Herbaria searched, in part or whole, are: A, AMES, AUA, bas (pers. herb. Bruce Sorrie), ctb (pers. herb. Charles Bryson), DUKE, FLAS, FSU, GA, GH, IBE, LSU, MISSA, Mississippi Museum of Natural Science, NCSC, NEBC, NCU, NLU, rjl (pers. herb. Richard LeBlond), US, USA, USCH, SWSL, VSC, and VDB (at BRIT). Names and boundaries of floristic provinces are derived from Thorne (1993) and Takhtajan (1986). MARCWJUNE 2001
Development of Phytogeographic Patterns From the source material listed above, we created county-level distribution maps for roughly 1000 coastal plain endemic taxa, especially those considered to be rare or uncommon. Whenever possible, peripheral and disjunct occurrences were verified or rejected based on direct examination of specimens. The maps were then compared for overlapping geographical areas which supported multiple taxa; that is, taxa which shared the same approximate boundaries. These areas usually corresponded to distinct geological, geographical, or edaphic factors. The mapped ranges differed by varying degrees; thus when we identified patterns we decided to be inclusive rather than too selective, since our objective was to recognize major distributional patterns, not a myriad of lesser polygons. We arbitrarily selected eight as the minimum number of taxa comprising a major pattern. Tmnomic Viewpoint Our taxonomic viewpoint favors "splitting," but by no means do we blindly accept all taxa of Small (1933) or Fernald (1950). We favor the recognition of a taxon as a full species if it can be demonstrated that it differs from related taxa by 1) distinct morphology, involving more than one character state; 2) distinct geographical range; 3) distinct habitat; 4) distinct biochemistry; 5) distinct genetic makeup. We rarely recognize species that are based on less than three of the above criteria. Recognition of a taxon a t infraspecific levels, however, may involve only one or two of the above criteria. We favor the views of Semple, Blok, and Heiman (1980, p. 159-1621, to treat genera narrowly, rather than broadly (e.g., a s a section). During the past three decades, botanists have documented distinct morphology, habitat fidelity, and different range for many taxa synonymized by Radford, Ahles, and Bell (1968), Gleason and Cronquist (1991), Gould and Clark (19781, and other authors of floristic works. Recent revisional papers, often supported by biochemical, genetic, or cladistic analyses, indicate a strong movement toward recognition of more rather than less taxa in the coastal plain. Moreover, new taxa, many of which are remarkably distinct species, are being described a t a steady rate (several per year) throughout the region (Hartman and Nelson 1998). Nomenclature Nomenclature follows Kartesz (1994), as emended by more recent monographs and taxonomic papers. Authorities of binomials are provided in Appendix 1. The body of this paper and Appendix 1contain selected taxa only; they do not constitute a complete listing of coastal plain endemics. RESULTS Numerical Summary of Endemics The number of taxa endemic to the Atlantic and Gulf Coastal Plains by taxonomic rank are: families-2; genera-47; species-1306; subspecies and varieties-297. Figures are taken from Sorrie and Weakley (in prep.); a more detailed summary can be found there. To provide perspective, these numbers may be compared with the total coastal plain flora of roughly 6000 native and 1950 alien taxa (Sorrie and Weakley, in prep.). These figures are subject to change in the future, given the changeable nature of taxonomic botany, and as more detailed distributional data become available. We recognize two endemic families: Dionaeaceae and Leitneriaceae, each with a single species. Of the 47 endemic genera, 34 (72%) are monotypic. Selected examples are given here, with the number of species per genus: Amphicarpum-2, Balduina-3, Brunnichia-1, Carphephorus-7, Ceratiola-1, Cymsciadium-1, Dicerandra-9, Dionaea-1, Franklinia-1, Garberia-1, Lachnanthes-1, Leitneria-1, Macbridea-2, Macranthera-1, Phanopyrum-1, Phoebanthus-2, Pinckneya1, Planera-1, Rhapidophyllum-1, Rhododon-2, Schwalbea-1, Serema-1, Stokesia-1, Vaseyochloa1, Warea-4, Zembia-1. From a phylogenetic perspective, it is interesting to note which genera and families have produced significant numbers of endemic species and infraspecific taxa. A total of 98 genera 54
CASTANEA VOLUME 66
have contributed five or more endemics. A full list of these may be obtained from the authors. Examples are (with number of endemics and family): Agalinis (25, Scrophulariaceae), Andropogon (12, Poaceae), Asclepias (17, Apocynaceae), Baptisia (12, Fabaceae), Carex: (30, Cyperaceae), Coreopsis (13, Asteraceae), Dalea (11, Fabaceae), Dicerandra (9, Lamiaceae), Dichanthelium (22, Poaceae), Eupatorium (14, Asteraceae), Euphorbia sensu stricto (11, Euphorbiaceae), Helianthemum (6, Cistaceae), Hypericum (23, Clusiaceae), Ilex (11, Aquifoliaceae),Juncus (9, Juncaceae), Liatris (19, Asteraceae), Lobelia (15, Campanulaceae), Matelea (7, Apocynaceae), Paronychia (16, Caryophyllaceae), Pinguicula (6, Lentibulariaceae), Polygala (19, Polygalaceae), Quercus (18, Fagaceae), R k i a (11, Melastomataceae), Rhynchospora (48, Cyperaceae), Sabatia (13, Gentianaceae), Sarracenia (11, Sarraceniaceae), Scutellaria (10, Lamiaceae), Sideroxylon (7, Sapotaceae), Sporobolus (8, Poaceae), Trillium (9, Trilliaceae), Vernonia (8, Asteraceae), Xyris (15, Xyridaceae), Zephyranthes (6, Amaryllidaceae). Phytogeographic Patterns The maps that accompany this paper depict distinct patterns of distribution. Each of these patterns circumscribes a limited geographical area, to which several to many species are confined-that is, they are endemic to that particular region. Such areas may be termed centers of endemism. Although such areas may in some cases be termed centers of speciation, the two terms are not synonymous, since a species which is now endemic to an area may not have evolved there. The geological and climatological processes that have shaped the coastal plain have provided plant species (and their progenitors) opportunities to move a s sea levels rose and fell, as climates changed, as hydrologies became altered, as crustal zones uplifted and downwarped, and as plant communities evolved. Centers of endemism represent localized areas where unique combinations of geological and environmental conditions have produced a suite of species adapted to those conditions. Some of these areas, such as the New Jersey Pine Barrens, the North Carolina-South Carolina pine savannas, the Lake Wales Ridge in central peninsular Florida, the Florida panhandle-southeastern Louisiana region (the East Gulf Coastal Plain), and the South Texas Plains may be known to readers. The following distribution patterns are arranged geographically, roughly north to south, thence westward. The number of taxa that fit a given pattern is estimated, followed by representatives. All taxa are listed for patterns harboring twenty or less. 1. Southeastern Massachusetts to southern New Jersey and adjacent Delmarva Peninsula. Figure 2. Over half of the endemics are distinct a t the varietal level only, perhaps reflecting the relatively short time period since glaciers or periglacial conditions prevailed. Fifteen taxa fit this pattern: Agalinis acuta, Crataegus chrysocarpa var. bicknellii, Erechtites hieraciifolia var. megalocarpa, Eupatorium leucolepis var. novae-angliae, Helianthemum dumosum, Melampyrum lineare var. pectinatum, Panicum dichotomiflorum var. puritanorum (disjunct to IN), Paspalum setaceum var. psammophilum, Pityopsis falcata, Polygonum pensylvanicurn var. nesophilum, Polygonum puritanorum, Rhynchospora knieskernii, Sagittaria teres, Sisyrinchium arenicola sensu stricto (disjunct to sw Nova Scotia), Viburnum dentatum var. venosum. No endemic genera. 2. Bimodal: southern New Jersey and Delawareleastern North and South Carolina. Figure 3. These taxa are absent or very rare in intervening Maryland, Virginia, and northeastern North Carolina. Their ranges may have been continuous in the late Pleistocene, but were divided by rising sea level in the Holocene. Eight taxa: Calamovilfa brevipilis, Dichanthelium hirstii (disjunct to southwest GA), Eupatorium resinosum, Gentiana autumnalis, Lobelia canbyi, Narthecium americanum (disjunct to montane NC), Pyxidanthera barbulata sensu lato (rare disjunct to southeastern NY), Rhynchospora pallida (disjunct to southeastern NY). One endemic genus: Pyxidanthera. Many other taxa are widespread on the coastal plain, but still show a disjunction between the Carolinas and New Jersey-Delaware. Examples are Cleistes divaricata, Lobelia boykinii, Lophiola aurea, Platanthera integra, Platanthera nivea, Polygala cymosa, Rhynchospora careyana, R. oligantha, Sclerolepis uniflora, Stylisma pickeringii var. pickeringii, Xyris fimbriata.
Figure 2. Phytogeographic patterns #I, #3, and #4. #1 (northern stippled area):southeastern Massachusetts to southern New Jersey and adjacent Delmarva Peninsula. #3 (southern stippled area): southeastern Virginia to southeastern Georgia. #4 (slanted lines): southeastern North Carolina to northeastern South Carolina.
3. Southeastern Virginia to southeastern Georgia. Figure 2. These taxa occupy the northeastern end of the range of longleaf pine (Pinus palustris), the species which defines the core area of endemism within the coastal plain. Although noted for its flat topography, this area supports a remarkable array of habitats. An estimated 25 taxa fit this pattern, but the total rises to 50 if patterns #4 and #5 are included (they are geographical subsets of #3). Examples are: Baptisia cinerea, Boltonia caroliniana, Carphephorus bellidifolius, C. tomentosus, Coreopsis falcata, Marshallia graminifolia ssp. graminifolia, Nuphar sagittifolia, Oenothera riparia, Parthenium integrifolium var. mabryanum, Ptilimnium sp. nov. aff. capillaceum, Sporobolus pinetorum, Vaccinium crassifolium ssp. crassifolium, Zenobia pulverulenta. One endemic genus: Zenobia. 4. Southeastern North Carolina to northeastern South Carolina. Figure 2. This pattern may be considered a subset of #3, but is restricted to the Cape Fear Arch geological region, generally within 175 km of Wilmington, NC. This small area has been documented as a n important area of speciation (LeBlond 2001). Seventeen taxa: Allium sp. nov. aff. cernuum, Amorpha georgiana var. confisa, Aristida stricta sensu stricto, Carex lutea, Dwnaea muscipula, Hypericum sp. nov. aff. brachyphyllum, Isoetes microvela, Kalmia cuneata, Lysimachia asperulifolia, Lysimachia loomisii, Scleria sp. nov. aff. ciliata (single disjunct population in piedmont), Solidago pulchra, Solidago villosicarpa, Solidago verna, Thalictrum cooleyi (single disjunct population in nw FL), 7bfieldia glabra, Trichostema sp. nov. aff. dichotomum, Zephyranthes sp. nov. &. simpsonii. One endemic genus: Dwnaea. 5. Fall-line Sandhills of central North Carolina to east-central Georgia. Figure 4. This pattern may be considered a subset of #3 or #4, but is restricted to the rolling hills and innumerable blackwater creeks of the inner coastal plain. Eight taxa: Astragalus michawcii, Liatris cokeri, 56
CASTANEA VOLUME 66
Figure 3. Phytogeographic patterns #2 and #6. #2 (stippled area): bimodal southern New Jersey and Delawareleastern North and South Carolina. #6 (slanted wavy lines): southern South Carolina to peninsular Florida westward to the central panhandle of Florida and southeastern Alabama.
Lilium sp. nov. aff.iridollae, Lobelia batsonii, Lycopus cokeri, Physalis lanceolata, Pyxidunthera barbulata var. brevifolia, Vaccinium crassifolium ssp. sempervirens. No endemic genera. 6. Southern South Carolina to peninsular Florida. Figure 3. These taxa are primarily Floridian
in distribution, extending northward to southern South Carolina and westward to the eastern portion of the Florida panhandle and southeastern Alabama. Although this pattern occupies a large geographical area, it may be considered a subset of #18 (longleaf pine). Important here is the migration barrier that the Savannah River creates-plants that cross it occupy only one or a few counties in southern South Carolina. Some taxa appear to be disjunct to South Carolina from Florida or from southernmost Georgia; this disjunction may be real, or from incomplete inventory, or from loss of habitat. An estimated 75 taxa fit this pattern. Examples are: Agalinis laxa, Aletris obovata, Andropogon brachystachyus, Arrwglossum floridanum, Asclepias connivens, Aster reticulatus, Carphephorus corymbosus, Desmodium floridunum, Dicerandra odoratissima, Dwscorea floridana, Dyschoriste humistrata, Elytraria caroliniensis var. caroliniensis, Erwchloa michauzii var. michaweii, Forestiera godfreyi, Galactia ellwttii, Hydrolea corymbosa, Nyssa ogeche, Paronychia americana ssp. americana, Pinckneya bracteata, Sererwa repens, Spartina bakeri, Tradescantia roseolens, Verbesina virginica var. laciniata. Two endemic genera: Pinckneya, Serenoa. Many other taxa share this range, but extend much farther westward on the Gulf Coastal Plain. Examples are Carex dusycarpa, Houstonia procumbens, Halesia diptera var. diptera, Kalmia hirsuta, Ludwigia arcuata, Lyonia ferruginea, Pieris phillyreifolia, Pinus ellwttii var. ellwttii, Pycnanthemum nudum, Quercus chapmanii, Sabatia bartramii, Sorghastrum secundum, and Sporobolus floridanus. MARCWJUNE 2001
57
Figure 4. Phytogeographic patterns #5, #7, #8, and #9. #5 (horizontal lines): fall-line sandhills of the Carolinas and east-central Georgia. #7 (stippled area): southeastern Georgia to northeastern Florida. #8 (slanted lines): Lake Wales Ridge. #9 (checkered area): subtropical Florida.
7. Southeastern Georgia to northeastern Florida. Figure 4. This pattern may be considered a subset of #6, but is confined to a much smaller area, in habitats dominated by pine flatwoods. As in pattern #3, there exists a broad array of habitats, despite little topographic relief. Fifteen taxa: Baptisia arachnifera, Baptisia calycosa var. calycosa, Calydorea coelestina, Conradina etonia, Ctenium floridanurn, Deeringothamnus rugelii, Dicerandra odoratissima, Dicerandra radfordiana, Franklinia alatamaha, Hartwrightiu floriduna, Hedyotis nigricans var. pulvinata, Helianthus carnosus, Orbexilum virgatum, Rhynchospora punctata, Verbesina heterophylla. Two endemic genera: Frankliniu, Hartwrightia. 8. Lake Wales Ridge. Figure 4. The central highlands of the Florida peninsula have been the subject of much botanical and conservation interest; see discussion in Huck et al. (1989).Here, we restrict our sample to those taxa which are endemic or near-endemic to Lake Wales Ridge proper, and exclude those which occur widely on the coastward sand ridges. An estimated 37 taxa fit this pattern. Examples are: Bonamia grandiflora, Carya floridana, Centrosema areni-
cola, Clitoria fragrans, Dicerandra cornutissima, Dicerandra frutescens, Dichanthelium ensifolium var. breve, Eryngium cuneifolium, Garberia heterophylla, Hypericum cumulicola, Ilex opacu var. arenicola, Liatris ohlingerae, Nolina brittoniana, Persea humilis, Polygala lewtonii, Polygonella myriophylla, Prunus geniculata, Quercus inopina, Stylisma abdita, Ziziphus celata. One endemic genus: Garberia. 9. Subtropical Florida. Figure 4. This pattern includes that portion of the peninsula from Lake Okeechobee southward. The area has derived much of its flora from the West Indian Floristic Province, yet 53 taxa are endemic just to south Florida. The Miami Rocklands and Big Pine Key appear to have been centers of speciation. Examples are: Aeschynomene pratensis var. pratensis, Agave decipiens, Chamaesyce deltoidea, Chromolaena frustrata, Cucurbita okeechobeensis 58
CASTANEA VOLUME 66
Figure 5. Phytogeographic patterns #lo, #11, #12, and #13. #10 (southern stippled area): East Gulf Coastal Plain. #11 (horizontal lines): central panhandle of Florida. #12 (slanted wavy lines): western panhandle of Florida. #13 (southern and northern stippled areas): widespread on East Gulf Coastal Plain, disjunct to the Carolinas.
var. okeechobeensis, Digitaria pauciflora, Galactia pinetorum, Harrisia aboriginum, Jacquemontia curtissii, Lantana depressa var. floridana, Lechea lakelae, Linum arenicola, Linum carteri, Melanthera paruifolia, Opuntia corallicola, Polygala smallii, Schizachyrium sericatum, Spermacoce terminalis, Stillingia sylvatica ssp. tenuis, Tragia saxicola. No endemic genera. Many other south Floridian taxa are also found locally in the Bahamas Islands, or in western Cuba, or in both countries: Aletris bracteata, Calopogon tuberosus var. simpsonii, Crossopetalum ilicifolium, Dyschoriste angusta, Evolvulus grisebachii, Polygala balduinii var. carteri, Selaginella eatonii, Spermacoce floriduna, Tripsacum floridanum, Vernonia blodgettii, others. 10. East Gulf Coastal Plain. Figure 5. Extending in a narrow belt from southwest Georgia to northwest Florida to southeast Louisiana, this area is one of the most important in terms of speciation and endemism. Moreover, when combined with patterns #11 and #12, it was an important refuge for plants during Pleistocene glaciation cycles. An estimated 83 taxa occur in this pattern, but the total rises to 122 if patterns #11 and #12 are included (geographical subsets of #lo). Examples are: Agalinis divaricata, Aster eryngiifolius, C a m baltzellii, Carphephorus pseudoliatris, Chasmanthium ornithorhynchum, Coelorachis tessellata, Drosera tracyi, Euphorbia floriduna, Gaylussacia mosieri, Helianthemum arenicola, Hypericum chapmanii, H. exile, Zsoetes louisianensis, Liatris chapmanii, Macranthera flammea (rare disjunct to se GA), Panicum nudicaule, Pinguicula primuliflora, Polygala chapmanii, Rhynchospora curtissii, Sarracenia leucophylla, Schizachyrium maritimum, Sorghastrum apalachicolense, Stachydeoma graveolens, Warea sessilifolia. Two endemic genera: Macranthera, Stachydeoma. 11. Central panhandle of Florida. Figure 5. This pattern may be considered a subset of #lo, but is confined to the six counties flanking the Apalachicola River. A few taxa extend into MARCWJUNE 2001
59
extreme southwestern Georgia or southeastern Alabama. The Apalachicola River basin was a n important refuge for plants during the Pleistocene and still harbors many relict populations of species ranging well to t h e north and west. In addition, it harbors several Arcto-Tertiary relicts. Twenty taxa: Arnoglossum album, Boltonia apalachicolensis, Cuphea aspera, Eriocaulon nigrobracteatum, Euphorbia telephwides, Gentiana pennelliana, Harperocallis flava, Justicia crassifolia, Liatris provincialis, Macbridea alba, Nyssa ursina, Phoebanthus tenuifolius, Physostegia godfreyi, Pinguicula ionantha, Rudbeckia graminifolia, Scutellaria floridana, Spigelia gentianoides var. gentianoides, T a u s floridana, Torreya taxifolia, Erbesina chapmanii. One endemic genus: Harperocallis. 12. Western panhandle of Florida and adjacent Alabama. Figure 5. This pattern m a y be considered a subset of # l o , but none of t h e taxa range west of t h e MobiletTensaw River delta. Like t h e Savannah River (pattern #6), the Mobilemensaw is a n important barrier to plant migrations. Nineteen taxa: Aster chapmanii, Aster spinulosus, Baptisia calycosa var. villosa, Chamaecyparis thyoides var. henryae, Chrysopsis godfreyi, Chrysopsis lanuginosa, Echinodorus floridanus, Hypericum lissophloeus, Lilium iridollae, Lupinus westianus var. westianus, Magnolia ashei, Nuphar ulvacea, Oxypolis filiformis ssp. greenmanii, Paronychia chartacea ssp. minima, Polygonella macrophylla, Potamogeton floridunus, Rhexia salicifolia, Scutellaria glabriuscula, Xyris isoetifolia, X. longisepala. No endemic genera. 13. Widespread on East Gulf Coastal Plain, disjunct to North and South Carolina. Figure 5. Existence of this pattern was discussed by Sorrie et al. (1997). Eleven taxa: Aristida mohrii, Carex turgescens, Lophwla aurea, Polygala hookeri, Rhynchospora crinipes, R. leptocarpa, R. macra, R . oligantha, Tridens carolinianus, Xyris chapmanii, X. scabrifolia. No endemic genera. Several other essentially Gulf Coastal Plain taxa, such as Aristidu simpliciflora, ErwcauLon texense, and Rhynchospora pleiantha, extend farther eastward onto t h e southern Atlantic Coastal Plain i n Florida or Georgia, but also are rare disjuncts to t h e Carolinas. 14. W e s t Gulf Coastal Plain. Figure 6. This area extends from west Louisiana to east Texas, southeast Oklahoma, and south Arkansas. I t includes the westernmost occurrences o f t h e longleaf pine ecosystem, but extends considerably beyond the known range of Pinus palustris. Historically, t h e vegetation has been heavily influenced b y t h e Prairie Floristic Province. For ecological summaries, see Harcombe et al. (19931, Hatch et al. (19901, and Orzell and Bridges (1987). An estimated 85 taxa fit this pattern. Examples are: Agalinis caddoensis, Amorpha paniculata, Astragalus soxmaniorum, Echinacea sanguinea, Gaura demareei, Lesquerella angustifolia, Liatris acidota, Liatris cymosa, Panicum brachyanthum, Pedwmelum hypogaeum var. subulatum, Physostegia longisepala, Polanisia erosa ssp. erosa, Rhynchospora glomerata var. angusta, Rudbeckia texana, Sagittaria papillosa, Scutellaria cardwphylla, Sporobolus silveanus, Streptanthus hyacinthoides, Tetragonotheca ludoviciana, Trillium gracile, Yucca louisianensis. No endemic genera. 15. W e s t Gulf coastal prairies and dunes. Figure 7. This maritime and near-coastal area extends from southwest Louisiana to east-central Tamaulipas, Mexico. A few taxa extend slightly eastward i n Louisiana. An estimated 46 taxa occur i n this pattern, of which 9 (20%)are grasses. Examples are: Boerhaauia mathisiana, Cakile geniculata, Cooperia traubii, Digitaria cognata var. arenicola, Euphorbia innocua, Hymenocallis galvestonensis, Hymenoxys texana, Lenophyllum texanum, Lesquerella lindheimeri, Rhododon angulatus, Sabatia arenicola, Samolus ebracteatus var. alyssoides, Sesuvium trianthemoides, Sporobolus tharpii, Thurovia triflora, Vaseyochloa multinervosa, Zephyranthes refugiensis. Two endemic genera: Thurovia, Vaseyochloa. 16. Carrizo sands. Figure 7 . Only 19 km (12 m i ) wide, the Carrizo Formation trends southwest to northeast for some 720 k m (450 m i ) , wholly within Texas. T h e deep sandy soil supports mostly oak scrub, described i n detail b y McBride (1933). T e n taxa fit this pattern; two more are mostly confined to this area. Abronia macrocarpa, Brazoria pulcherrima, Chaetopappa imberbis (mostly), Coreopsis nuecensis (mostly),Crataegus nananixonii, Hymenopappus carrizoanus, Monarda viridissima, Palafoxia hookeriana var. minor, Paronychia setacea, Polygonellaparksii, Rhododon ciliatus, Thelesperma flavodiscum. No endemic genera. 60
CASTANEA VOLUME 66
Figure 6. Phytogeographic patterns #14 and #17. #14 (stippledarea):West Gulf Coastal Plain. #17 (slanted lines): south Texas-northeast Mexico mesquital.
17. South Texas-northeast Mexico Mesquital. Figure 6. This area's plantlife has been heavily influenced by the Sonoran Floristic Province. Although the area occurs geologically on the coastal plain, Thorne (1993) includes it within the Tamaulipan Subprovince of the Sonoran Floristic Province. The northern portion is commonly denoted as the South Texas Plains, but ecologically the whole area is more properly termed the Tamaulipan Scrub region, or Tamaulipan Mesquital, due to the dominant shrubby vegetation, especially Prosopis glandulosa Torr. (Crosswhite 1980). It is a n important area of speciation-an estimated 96 taxa occur only here. Examples are: Adelia uaseyi, Atripla klebergorum, Brazoria arenaria, Callisia micrantha, Coryphantha macmmeris var. runyonii, Cuscuta runyonii, Eleocharis austrotexana, Frankenia johnstonii, Gilia ludens, Grindelia oolepis, Houstonia correllii, H. croftiae, Justicia runyonii, Lesquerella thamnophila, Manfreda longiflora, Manihot walkerae, Matelea parviflora, Cbcalis berlandieri, Pamnychia lundellorum, Stachys drummondii, Thelesperma nuecense, Thelypodwpsis shinnersii, Trichoneura elegans, Xylothamia palmeri. No endemic genera. 18. Longleaf pine. A very extensive area, extending from southeast Virginia to central Florida to east Texas. Figure 8. This broad range encompasses the core area of endemism and speciation within the Atlantic and Gulf Coastal Plains Floristic Province. Phytogeographical patterns #3-8 and 10-14 (in part) are regional subsets of Longleaf Pine. For ecological summaries, see Harcombe et al. (19931, Peet and Allard (19931, and Ware et al. (1993). Walker (1993) discusses rare andlor endemic species associated with longleaf pine communities. At least 440 taxa occur in this pattern, not counting those of regional subsets. Examples are: Agalinis aphylla, Aletris aurea, Andropogon mohrii, A. tracyi, Anthaenantia rufa, Aristida condensata, Balduina uniflora, Bartonia verna, Calopogon barbatus, Carez uerrucosa, Carphephorus odoratissimus, Ceratwla ericoides, Chapmannia floridana, Chaptalia tomentosa, Chrysoma pauciflosculosa, Coreopsis linifolia, Cliftonia monophylla, Ctenium aromaticum, Desmodium tenuifolium, MARCWJUNE 2001
61
Figure 7. Phytogeographic patterns #15 and #16. #15 (stippled area): West Gulf coastal prairies and dunes. #16 (short lines): Carrizo sands.
Eupatorium glaucescens, Helianthemum carolinianum, Hypericum setosum, Juncus trigonocarpus, Leucothoe axillaris, Lilium catesbaei, Lindera subcoriacea, Linum floridanum var. floridanum, Ludwigia pilosa, Macbridea caroliniana, Magnolia grandiflora, Phoebanthus grandiflorus, Piloblephis rigida, Pinus palustris, Pleea tenuifolia, Polygonella polygama var. polygama, Quercus hemisphaerica, Q. laevis, Rhapidophyllum hystrix, RhQia alifanus, R. lutea, Rhynchosia difformis, Rhynchospora debilis, R. latifolia, Sabatia gentianaides, Solidago patula var. strictula, Stipulicida setacea, Stokesia laevis, Stylisma aquatica, Stylodon carneus. Fifteen endemic genera: Anthaenantia, Balduina, Carphephorus, Ceratwla, Chapmannia, Chrysoma, Cliftonia, Dicerandra, Macbridea, Phoebanthus, Piloblephis, Pleea, Rhapidophyllum, Stipulicida (disjunct to Cuba), Stokesia. 19. Widespread, including the Mississippi Embayment. Figure 1. Although several hundred coastal plain endemics occur in southern Mississippi, Louisiana, and southern Arkansas, only a relatively small number extend northward. An estimated 60 taxa fit this pattern, including 4 taxa which are endemic (or nearly so) just to the Embayment. Examples are: Acer rubrum var. drummondii, Brunnichia ovata, Carex bicknellii var. opaca (M. E. endemic), Carex socialis, Catalpa specwsa (originally an M. E. endemic), Crataegus marshallii, Eupatorium semiserratum, Glyceria arkansana ( M . E. near-endemic), Hydrolea ovata, Lindera melissifolia, Lysimachia radicans, Mespilus canescens (M. E. endemic), Nyssa aquatica, Phanopyrum gymnocarpon, Planera aquatica, Quercus pagoda, Saccharum baldwinii, Taxodium distichum, Thalia dealbata, Trepocarpus aethusae. Four endemic genera: Brunnichia, Leitneria, Planera, Trepocarpus. 20. Widespread, disjunct to southwestern Nova Scotia. Figure 9. Roland and Smith (1969) discuss the disjunctions and floristic affinities of the Nova Scotia flora. Nineteen taxa: Atriplex pentandra, Clethra alnifolia var. alnifolia, Coreopsis rosea, Drosera filifbrmis, Eleocharis tuberculosa, Eupatorium dubium, Glyceria obtusa, Zlex glabra, Iris prismatica, Zva frutescens ssp. 62
CASTANEA VOLUME 66
Figure 8. Phytogeographic pattern #18. Stippled area: core region of longleaf pine (Pinuspalustris). Dotted line: area of discontinuous or disjunct occurrences of longleaf pine. After Ware, Frost, and Doerr (1993).
oraria, Juncus caesariensis, Lachnanthes caroliniuna, Lilaeopsis chinensis, Lophwla aurea, Platanthera flava var. flava, Sabatia Izennedyana, Sisyrinchium arenicola sensu stricto, Scirpus longii, Solulugo latissimifolia. No endemic genera. 21. Widespread, disjunct to the Great Lakes region. Figure 9. Analyses of this pattern can be found in Jackson and Singer (1997) and Reznicek (1994). It must be noted that many of the "coastal plain" taxa treated by these authors are not endemic in the sense that we use. While such taxa may have originated on the coastal plain, they now range over a much broader area. Only the following 9 taxa fit our criteria: Eleocharis melanocarpa, E. tricostata, Fuirenapumila, Lipwarpha maculata, Ludwigia sphaerocarpa, Lycopus amplectens, Proserpinaca pectinata, Rhynchospora scirpoides, Scleria reticularis sensu stricto. No endemic genera. 22. Widespread, disjunct to central Tennessee andlor Kentucky. Figure 10. Disjunction to the Eastern Highland Rim and Cumberland Plateau regions of these states has been the subject of papers by Braun (1936, 1937), Harvill (1984), Pyne (20001, and Svenson (1941). A surprisingly large number of taxa fit this pattern-estimated a t 58. Examples include: Agalinis obtzlsifolia, Carex barrattii, C. collinsii, Chasmanthium laxum, Clethra alnifolia var. alnifoliu, Eleocharis tortilis, Eupatorium leucolepis var. lerccolepis, Fimbristylis perpusilla, Iris prismatica, Juncus ellwttii, Lachnanthes caroliniana, Lespedeza angustifolia, Ludwigia hirtella, Muhlenbergia torreyana, Platanthera integra, Platanthera nivea, Proserpinaca pectinata, Rhynchosiu difformis, Rhynchospora chalamephala, R. latifolia, Schwalbea americana, lbfieldia racemosa, Xyris fimbriata. No endemic genera.
Figure 9. Phytogeographic patterns #20 and #21. #20 (stippled area and area with slanted lines): widespread, disjunct to Nova Scotia. #21 (stippled area and areas with horizontal lines): widespread, disjunct to Great Lakes region.
The Ridge-and-Valley portions of northeastern Alabama and northwestern Georgia harbor a number of these same taxa, plus some other disjunct taxa not found in Tennessee or Kentucky. The Alabama and Georgia plants may form a distinct phytogeographic pattern, but data are incomplete a t this time. Similarly, data on disjunctions to the southeastern portion of the Blue Ridge in North and South Carolina have not been fully analyzed, but it is likely that they will form a discrete pattern. 23. Widespread, disjunct to northwestern Virginia. Figure 10. Fleming and Van Alstine (1999) discuss this pattern in depth. Only the following 9 taxa fit our criteria: Carex barrattii, Ekocharis melanocarpa, Lachnanthes caroliniana, Glyceria obtusa, Magnolia virginiana, Panicum hemitomon, Stachys hyssopifolia var. hyssopifolia, Utricularia striata, Viburnum nudum var. nudum. No endemic genera. 24. Widespread, disjunct to western Cuba. Figure 11. Western Cuba includes the provinces of Habana, Isla de Pinos (Isla de Juventud), Matanzas, and Pinar del Rio. Nearly all of the plants listed here are found as disjuncts to Cuba only. A number of the "widespread" taxa are confined in the United States to the Florida peninsula. In compiling the taxa for this pattern, Leon and Alain (194663) and Liogier (1969) have been indispensable resources. Some of these taxa may eventually prove to be too common in Cuba to be considered rare/uncommon disjuncts, but we include them until better data are a t hand. Forty-two taxa: Agalinis linifolia, Aristida spiciformis, Amnopus fircatus, Bidens mitis, Bulbostylis stenophylla, Cyperus ovatus, Dichanthelium erectifolium, D. wrightianum, Digitaria serotina, Echinodorus parvulus, Eleocharis microcarpa var. microcarpa, Fuirena scirpoidea, Hypericum tetrapetalum, Hypoxis juncea, Juncus repens, 64
CASTANEA VOLUME 66
Figure 10. Phytogeographic patterns #22 and #23. #22 (stippled area and areas with slanted wavy lines): widespread, disjunct to central Tennessee andlor southeastern Kentucky. #23 (stippled area and area with crosshatching): widespread, disjunct to northwestern Virginia.
Kbsteletzkya virginica, Lachnanthes caroliniana, Lachnocaulon anceps, L. engleri, Lycium carolinianum var. carolinianum, Lycopodiella alopecuroides, Lyonia lucidu, Lythrum lineare, Oenothera humifusa (also Bermuda), Panicum chamaelonche, I? virgatum var. cubense, Proserpinaca pectinata, Pteroglossaspis ecristata, Reimarochloa oligostachya,Rhynchospora cephalantha var. microcephala, R. grayi, R. pleiantha, R. wrightiana, Sabatia calycina (also Dominican Republic), S. grandiflora, Setaria corrugata, Solidago stricta, Tephrosia chrysophylla, Thelypteris hispidula var. versicolor, Tripsacum floridunum, Vicia acutifolia, Xyris caroliniana. No endemic genera. A number of other taxa are disjunct to both Cuba and the Bahamas. A small number, mostly grasses and sedges, are disjunct to Cuba and Central America, particularly to the pine savannas of Belize, Honduras, and Nicaragua. 25. Widespread, disjunct to the Bahamas. Figure 11.These disjunctions are nearly all confined to the northwestern islands which support forests or savannas of Caribbean pine (Pinus caribaea) over oolite: Abaco, Andros, Grand Bahama, New Providence. A number of the "widespread taxa are confined in the United States to the Florida peninsula. Correll and Correll (1982), and Sorrie and LeBlond (1997) document the Bahamas disjuncts. Twenty-two taxa: Agalinis harperi, Andropogon capillipes, A. longiberbis, A. virginicus var. decipiens, Aster adnatus, Borrichia frutescens (also Bermuda), Chamaecrista nictitans var. aspera, Cyperus distinctus, Encyclia tampensis, Erigeron quercifolius, Hymenocallis latifolia, Juncus roemerianus, Liatris garberi, Mentzelia floridana, Mitreola sessilifolia, Persea palustris, Pinguicula pumila, Selaginella eatonii, Seymeria cassioides, Sisyrinchium nashii, Thelypteris ovata var. ovata, Vernonia blodgettii. No endemic genera. Other taxa, such as Scleria baldwinii, are disjunct to both Cuba and the Bahamas. 26. Bimodal: coastal plainIAppalachian Mountains. Although of minor importance in terms of MARCWJUNE 2001
65
Figure 11. Phytogeographic patterns #24 and #25: widespread, disjunct to western Cuba (#24) or to northwestern Bahamas (#25).
the number of taxa, this pattern is well-known to most botanists. The origins of the taxa (whether coastal plain or montane) remain obscure for some. Only three taxa fit our 90% criterion to be considered coastal plain endemics, the rest (asterisks) are too numerous in the mountains but are included for interest. Cleistes bifaria*, Gaylussacia dumosa var. bigeloviana*, Helonias bullata (Figure 12), Juncus caesariensis, J.gymnocarpus*, Lewphyllum buxifolium*,Narthecium americanum, Xerophyllum asphodeloides*. Endemic genera: Helonias. Zigadenus leimanthoides is by some considered to have a bimodal coastal plainlmontane distribution, including robust plants of seepage bogs on the East Gulf Coastal Plain. However, unpublished work by W. McDearman (in litt.) suggests that the Gulf Coast "leimanthoides" actually is Z. densus, merely with branched inflorescences. The remaining Z. leimanthoides of the mountains and northern Atlantic Coastal Plain are specifically distinct from 2. densus, and thus fit the bimodal pattern discussed above.
27. Bimodal: peninsular Floridalsouthern Texas. Figure 13. So far as is known, the following 9 taxa are restricted to the coastal plain portions of Florida and Texas: Cakile lanceolata ssp. pseudoconstricta, Chrysopogon pauciflorus (also in western Cuba), Croton glandulosus (var. floridanus in FL, var. pubentissimus in TX),Digitaria texana, Machaeranthera phyllocephala, Paspalum monostachyum (rare in sw LA), Spermacoce floridana (also nw Bah.), Spigelia loganwides, Stylisma villosa. No endemic genera. DISCUSSION Comparison with Other Floristic Provinces The large number of endemic taxa and the wide range of distribution patterns clearly document the importance of coastal plain vascular plants to North American biodiversity. These numbers provide solid evidence for the statements regarding endemism by Takhtajan (19861, 66
CASTANEA VOLUME 66
Figure 12. Phytogeographic pattern #26: bimodal, coastal plain1Appalachian Mountains. As an example we depict the range of Helonias bullata.
Thorne (1993), Ricketts et al. (19991, and Stein, Kutner, and Adams (2000). The Atlantic and Gulf Coastal Plain Floristic Province stands in the front rank of floristic regions in North America. North of Mexico, only the California Floristic Province supports more endemic genera (50+) and species (about 2000, Thorne 1993). Figures have not been published for the Appalachian Floristic Province, but we estimate only 7 endemic genera. Many other genera that are restricted to this province in North America also occur in eastern Asia; still others are widespread in adjacent North American provinces. Thorne (1993) states that "specific endemism is very high in this province," but cites no figures. The Prairies Floristic Province supports 87 endemic species and infraspecific taxa, but no endemic genera (C. Freeman, pers. comm.). The Vancouverian Floristic Province (including the Sierra Nevada of California and the Klamath Ranges of CaliforniafOregon) supports a t least 11 endemic genera and up to 600 endemic species (Thorne 1993). The Great Basin Floristic Province appears to have a high rate of endemism-about 25% according to Thorne (1993). Figures compiled by Kartesz and Farstad (1999) indicate that a t least 539 species are endemic to this region (the sum of their ecoregions #42, 75, 76, 78). The Rocky Mountain Floristic Province supports some 5 endemic genera and an unknown number of endemic species (out of 4000-4500 total species, Thorne 1993). The relative lack of floristic diversity in the Arctic and Canadian Floristic Provinces renders them far short of the coastal plain in endemics. Turning to the southernmost portions of North America, The Sonoran Floristic Province supports well over 20 endemic genera and over 1300 endemic species (figures compiled from Raven and Axelrod 1978, Thorne 1993). The Mexican Highlands Floristic Province, confined to Mexico north of the Isthmus of Tehuantepec, appears to be the most diverse of any North American province. Certainly it has the highest rate of endemism-roughly 4900 species, or 70% of its 7000 total species, are considered to be endemic (Rzedowski 1993). MARCWJUNE 2001
67
Figure 13. Phytogeographic pattern #27: bimodal, peninsular FloridalsoutheasternTexas.
Pathways to Endemism Endemic taxa arise through the process of speciation; that is, the development of new gene combinations in separate populations and the formation of reproductive isolating mechanisms (Grant 1981). Endemics may result from several basic pathways. 1)Populations of a widespread species may develop adaptations to local edaphic conditions. This may occur a t the edge of the species' range or well within it. Examples are numerous, but include Lycopus cokeri, adapted to wet streamheads in the North Carolina-South Carolina sandhills; and Rhododon ciliatus and other taxa restricted to the Camzo Sands formation of Texas. 2) Populations may become established after long-distance dispersal events, eventually leading to speciation. Examples are Willkommia texana, with one variety in Texas and another in Argentina; and Licania michauxii, the sole coastal plain representative of a large pan-tropical genus. 3) Populations may become relictual following major climatic changes. These may be very old events, such as the splitting up of Arcto-Tertiary species, or recent, such a s following the Hypsithermal event. Examples are Torreya taxifolia, Narthecium americanum, Mentzelia floridana, and Dicerandra spp. (Huck et al. 1989). 4) Populations may develop genetic anomalies, such a s agamospermy (apomixis), which may result in reproductive isolation. Examples are Crataegus nananixonii and Eupatorium glaucescens. 5) Populations may diverge from a widespread species through temporal isolation. For example, !l'of;eldia glabra is embedded within the range of I: racemosa and inhabits the same plant communities, but has become reproductively isolated by flowering two months later, when I: racemosa has set seed. Endemism in the Coastal Plain The underlying reasons for the remarkable endemism of the coastal plain, and for the various endemic distribution patterns, are not obvious. The casual observer may be inclined to 68
CASTANEA VOLUME 66
consider the coastal plain devoid of many characteristics considered likely to generate evolutionary innovation. The coastal plain has few obvious geographic dividers, has very subdued topography (maximum elevation is less than 244 m or 800 R), is of relative geologic youth, has an absence of striking edaphic factors (such as serpentine geology), and has a relatively homogeneous climate. This seeming incongruity was noted by Gentry (1986): "There is a conspicuous but often overlooked second center of endemism in temperate North America, in the southeastern coastal plain. This area of high local endemism is best developed in Florida but extends across the border into Georgia and Alabama. It is remarkable that Florida, only 152,000 sq. km and with virtually no topographic relief, should rank second only to California . . . in number of endemic species; it is even more remarkable when we consider that the endemic plant species are concentrated in northern and central Florida, not in the subtropical southern part." Evidence to support observed biodiversity on the coastal plain comes primarily from five sources: 1)the geographic placement of the coastal plain at the climatic ecotone between temperate and tropical systems, and (at its western end) between moist and dry climatic regimes; 2) the coastal plain flora is derived from moist temperate, dry temperate, moist tropical and dry tropical components; 3) the edaphic diversity is deceptively great, and some biogeographic barriers do exist; 4) the flora is older than it may seem, a t least in part; and 5) several different parts of the coastal plain have functioned as refugia (and possibly also as places of origin) for many taxa, for various geologic reasons. These five points are discussed individually below.
Continental Ecotone Graham (1999) documents a wide diversity of climates and floras on the coastal plain over the past 80 million years. For instance, "During the Middle Eocene the southeastern United States was occupied by a semideciduous tropical dry forest . . . On sandy sites Pinus and palmetto-like palms (Sabal-Serenoa type) were present and represent an earlier version of the modern sand pine scrub of the pine woods association. The broad sequence of communities in the southeastern United States has been a late Cretaceous tropical forest with no exact modern analog; a Paleocene through early Eocene tropical rain forest; a Middle Eocene tropical dry forest; and with subsequent decline of the tropical dry components, the appearance, diversification, and expansion of various associations comprising the modern Appalachian coniferous forest formation." More recently, Pleistocene and Holocene climates have continued to fluctuate strongly, with boreal elements reaching Georgia and Louisiana during the Wisconsin glaciation (23-16.5 thousand yr B.P.), and subtropical elements reaching a t least as far north as Virginia during warmer periods (Delcourt and Delcourt 1981, Graham 1999). Dressler (1954) and Miranda and Sharp (1950) discuss the importance of rainfall patterns in the Tertiary aged plant disjunctions between the eastern Mexican highlands and eastern United States. Derivation of Endemics Thorne (1993) states that "because of repeated Pleistocene inundations, it [the Coastal Plain Province] has a young flora recruited largely from the much more ancient Appalachian Province, and to a lesser extent from the West Indian Province to the south and the North American Prairies Province to the west." An analysis if the biogeographic affinities of genera which have endemic species or infraspecific taxa in the coastal plain suggests that the tropical/ subtropical flora of the West Indian Province, the Sonoran Province, and perhaps others, is much greater than suggested by Thorne. The following 75 genera of tropicaYsubtropica1affinities have endemic taxa on the coastal plain: Aeschynomene, Agalinis, Agarista, Andropogon, Aristida, Asclepias, Asimina, Baccharis, Bacopa, Bejaria, Bonamia, Buchnera, Bulbostylis, Caesalpinia, Callisia, Chamaecrista, Chloris, Clethra, Coelorachis, Ctenium, Cynanchum, Cyperus, Desmanthus, Digitaria, Dyschoriste, Elephantopus, Elytraria, Epidendrum, Eriocaulon, Eustachys, Evolvulus, Fimbristylis, Fuirena, Galactia, Gaylussacia, Glandularia, Habenaria, Hymenocallis, Hypoxis, Indigofera, Justicia, Lantana, Licania, Lindernia, Lobelia, Lycium, Lycopodiella, Manihot, Matelea, Mecardonia, Mimosa, Paspalum, Phyllanthus, Pluchea, Reimarochloa, Rhynchosia, Rhynchospora, Sageretia, Schizachyrium, Schoenocaulon, Scleria, Sebastiania, MARCWJUNE 2001
69
Selaginella (in part), Sideroxylon, Smilax, Stillingia, Syngonanthus, Tephrosia, Tillandsia, Triphora, Vernonia, Xyris, Zanthoxylum, Zephyranthes, Zornia. Another smaller set of genera show particular West Indian affinities: Crossopetalum, Harrisia, Kalmia, Lachnocaulon, Sabal, Thrinax. A large number of genera have predominantly temperate affinities. Some of these have centers of diversity in the Appalachian Province, while others are widespread or have a n eastern North American-eastern Asian Arcto-Tertiary relictual disjunct pattern of distribution. The following 71 temperate genera have endemics on the coastal plain: Aesculus, Aletris, Allium, Alnus, Amsonia, Aquilegia, Campanula, Carex, Carpinus, Castanea, Catalpa, Chionanthus, Cornus, Corydalis, Crataegus, Dryopteris, Ellwttia, Eupatorium sensu stricto, Fothergilla, Fraxinus, Gelsemium, Gentiana, Glyceria, Gordonia, Gratiola, Halesia, Helonias, Hexastylis, Lespedeza, Leucothoe, Lilium, Lindera, Lycopus, Lysimachia, Lyonia, Magnolia, Melampyrum, Narthecium, Nuphar, Nyssa, Oenothera, Osmanthus, Parnassia, Phlox, Pieris, Pinguicula, Platanthera, Prunus, Pycnanthemum, Rhododendron, Robinia, Sabatia, Sarracenia, Silene, Spigelia, Spiranthes, Stachys, Stewartia, Taxus, Tilia, Tofkldia, Torreya, Trifolium, Trillium, Ulmus, Valerianella, Viburnum, Vicia, Viola, Vitis, Wisteria, Zigadenus. It is interesting to note that some of the Arcto-Tertiary components are well-represented in the Appalachian Province, while others are not (Catalpa, Gordonia, Osmanthus, Taxus, Torreya). Although having montane components, Fothergilla, Helonias, Sabatia, and Sarracenia are much better represented on the coastal plain (e.g., Sabatia with 1 3 endemic taxa) and may well have evolved there. A smaller but significant group of genera have affinities with the Sonoran Floristic Province to the west and southwest. Thorne (1993) considered the Tamaulipan scrub area (northeast Mexico-south Texas) to belong within the Sonoran Province (as the Tamaulipan Subprovince), even though most of the area occurs on the geologic coastal plain. He therefore did not include its many endemics in his discussion of the Coastal Plain Province, even though he recognized that it ". . . add[sl greatly to the diversity of the [North American] flora." The following 32 Sonoran genera have endemics on the coastal plain: Abronia, Agave, Astragalus (in part), yphantha, Croptilon, Dalea, Echinocereus, Forestiera, Gaura, Hoffmannseggia, Houstonia (in part), Isocoma, Lenophyllum, Lesquerella, Lupinus (in part), Machaeranthera, Manfreda, Mentzelia, Nolina, Opuntia, Orbexilum, Palafoxia, Penstemon (in part), Piptochaetium, Polanisia, Pomaria, Psilactis, Quercus (in part), Selaginella (in part), Selenia, Sporobolus, Thelesperma, and Xylothamia. Many endemics belonging to these genera are confined to areas west of the Mississippi River, especially in Texas, but a substantial number occur well eastward, particularly in edaphically xeric sandhills, dunes, and Carolina bay rims. As climate changes occurred, the coastal plain was exposed to genetic material from several discordant floras. Taxa with tropical or subtropical affinities are very numerous, especially in the southern portions of the province, but many extend surprisingly far north (e.g., ~ o ~ h i o l a aurea, Persea palustris). Similarly, western elements reach well to the east. Some of the more notable ones are now disjunct relicts as far east as the Carolinas (Astragalus michauxii, Dalea pinnata, Eriogonum tomentosum, Nolina georgiana) and Florida (Mentzelia floridana, Palafoxia feayi).
or-
Edaphic Diversity and Biogeographic Barriers The edaphic diversity of the coastal plain is greater than is often appreciated. Eight of the ten soil orders recognized worldwide are represented in the coastal plain: Alfisols, Entisols, Histisols, Inceptisols, Mollisols, Spodisols, Ultisols, and Vertisols (Buol 1973). Soil pH ranges from about 3.0 to 9.0. Part of the complexity of coastal plain soils is due to their origin as 1) sediments from erosion of the Appalachian and Ozarkian massifs and 2) marine depositions. Extensive wetlands of diverse hydrology are present, as well as uplands with mesic to highly xeric conditions. Christensen (1988) states: "Much of this [community] variation is a consequence of dramatic gradients in physical and chemical characteristics of soils and hydrology. In addition, the southeastern Coastal Plain has the most diverse assemblage of freshwater wetland communities in North America and its lengthy and complex shoreline is populated by a rich array of marine ecosystems." CASTANEA VOLUME 66
Coarse sand areas (both xeric and wet) are particularly notable for their rich endemism. Such areas of porous sandy soils have functioned as edaphic islands and have generated considerable diversification (Clewell 1986, Huck et al. 1989, James 1961, McBride 1933). Notable examples are the Lake Wales Ridge in Florida, the Fall-line sandhills of the Carolinas and Georgia, the sandhills of the East Gulf Coastal Plain, and the Carrizo sands of Texas. Exposures of consolidated rocks, uncommon and local on the coastal plain, provide additional opportunities for endemism. Fortunately, most such areas have been studied (George and Nixon 1990, Harper 1906, LeBlond 2001, Snyder et al. 1991). Notable examples are the Altamaha Grit in Georgia (sandstone), the Weches and Catahoula glades in Texas and Louisiana (limestone), the south Florida rockland (oolitic limestone), and the Cape Fear Arch region in the Carolinas. As a result of the complex interplay of soils and moisture, "community physiognomy varies across the landscape from grasslands and savannas to shrublands, to needle- and broadleaved sclerophyllous woodlands, to rich mesophytic forest. These differences can be observed over a distance of only a few hundred meters and an elevational gradient of only 10 m." (Christensen 1988). In fact, shifts from one soil type to another may occur over much shorter distances and lesser gradients; such shifts may be abrupt and effect a marked change in floristic composition (pers. obs.). Witness the often rapid shift from pine-oak scrub to pine savanna to pond cypress depresson, a common occurrence from North Carolina to Louisiana, or the remarkably tight mosaic of upland and wetland species in the "pimple mound region of southwestern Louisiana-eastern Texas. There are several biogeographic breaks which can be correlated with plant distributions. The most obvious is the Mississipp-Atchafalaya River floodplain, which varies from about 50150 k m wide. Most coastal plain endemics occur only east or west of it. However, its effectiveness as a barrier seems to vary considerably depending on individual species' dispersal capabilities. Some taxa make only a token presence east (Herbertia lahue) or west (Aktris lutea) of the river, while Pinus palustris and Rhexia alifanus have very successfully crossed the barrier. Other large southern rivers, such as the Cape Fear, Cooper-Santee, Savannah, Apalachicola-Chattahoochee, Mobile-Tensaw-Alabama, Pearl, Red, and Sabine, have much less of an effect on species distributions. Nonetheless, all of them are apparent barriers to at least a few taxa, and so cumulatively have played an important role in shaping the ranges of endemics. For example, taxa in pattern #12 do not cross the Mobile-Tensaw-Alabama basin, and taxa in pattern #6 barely cross the Savannah River. Ctenium aromaticum and Rhexia alifanus are common members of western Louisiana savannas (having managed to hurdle the Mississippi-Atchafalaya floodplain), yet C. aromaticum is unknown across the Sabine River in Texas and R. alifanus is rare there. Another major biogeographic break is associated with the geologic Salisbury Embayment in eastern Virginia (which is the topographic Chesapeake Bay). Many coastal plain endemics do not occur north of this barrier, such as Pinus palustris, Andropogonglaucopsis, Rhynchospora latifolia, Erigeron vernus.
Age of the Flora The large number of genera (47) endemic to the Atlantic and Gulf Coastal Plains suggests that it represents an old flora, at least in part. Yet, even today some would argue that the flora is young. Thorne (1993) states that "Because of repeated Pleistocene inundations, it [the coastal plain1 has a young flora recruited largely from the much more ancient Appalachian Province . . . Although many of the floristic elements are apparently of very recent origin, many presumably archaic genera are represented, such as Ceratiola, Croomia, Dionaea, Franklinia, Gordonia, Zllicium, Leitneria, Rhapidophyllum, Sarracenia, Schisandra, T m d i u m , T m u s , and Torreya, in addition to the many more widespread Arcto-Tertiary (or Boreo-tropical genera)." This statement itself seems to suggest that a substantial portion of the coastal plain flora is indeed old. We believe that until very recently, paleoecologists and phytogeographers did not have sufficient data from which to draw conclusions regarding age. The quandary of ancient genera occurring on geologically young terrain can perhaps be explained by the following argument. Reconstructions of the coastal plain depicted by Hunt MARCWJUNE 2001
71
(1974, p. 218), Walker and Coleman (1987, p. 65), and Beyer (1991, p. 1791, suggest that portions of the coastal plain have been available for plant colonization since the Eocene epoch (early Tertiary period, 50 million yr B.P.). Walker and Coleman (1987) state that "Between the Cretaceous and the end of the Tertiary, there was a cumulative (albeit at variable rates) lowering of relative level to near the position of the present shoreline." Advancing seas did not cover all of the coastal plain during each advance. For example, about 2 million years B.P., just prior to the onset of the Pleistocene, the Atlantic Ocean advanced up to what is now termed the Orangeburg Escarpment, roughly 90 m above present sea level. There remained a greatly reduced (but still considerable, even if fragmented) area of the coastal plain which was available for plant colonization and which also probably served as a refugium for archaic taxa (James 1961). Each successive Pleistocene inundation covered less area than the previous advance, leaving an increasing amount of exposed land as time passed (Beyer 1991, Fenneman 1938, Walker and Coleman 1987). Through examination of pollen cores, Delcourt and Delcourt (1981) have demonstrated that, during the past 40,000 years, much of the Gulf Coastal Plain and southern Atlantic Coastal Plain supported vegetation not drastically different than that of the present. Pleistocene climates in the deep south were apparently moderated by warm ocean temperatures and this area did not support boreal floras, except very locally. Moreover, during full glacial peaks, the land area was greatly expanded, as lowered sea level exposed the formerly submerged continental shelf. Migrations of plants onto and off the shelf provided opportunities for additional speciation and for persistence in refugia. Finally, near-coastal environments of the middle Atlantic region may not have been as cold as the Delcourt maps (1981) might suggest. Throughout the Atlantic coast, plants have been documented to grow naturally far north of where the same species grow inland. As an example we offer Lophwla aurea, primarily an East Gulf Coastal Plain species, which grows on lakeshores and streamside marshes in Nova Scotia, surrounded by spruce-fir communities. There is no reason to doubt that this phenomenon also occurred during the Pleistocene and may have contributed to the persistence of coastal plain endemics even a t mid-Atlantic latitudes. An example might be Dwnaea muscipula, which has no close relatives and which has never been found growing naturally outside of a small area of the Carolinas and has not been detected in pollen cores southward. At this latitude the Delcourt maps suggest that at the peak of the Wisconsinan Glaciation (18,000 yr B.P.), jack pine-spruce forest covered the landscape. Could it be that Dionaea survived by migrating laterally rather than longitudinally? As Christensen (1988) states, "Perhaps the southern forest elements extended farther north near the coast, much as they do today, but evidence to test this hypothesis is now submerged and perhaps obliterated by coastal processes." As stated a t the outset of this section, we have documented the existence of 47 genera which are endemic to the coastal plain, or which also occur as rare disjuncts in other phytogeographic provinces. Some of these genera may have evolved relatively recently and some long ago, but conclusive data are lacking. That a large percentage of the endemic genera are probably archaic is suggested by this fact: 34 of the 47 (72%) are monotypic. Examples are Brunnichia, Ceratiola, Chapmannia, Chrysoma, Dionaea, Garberia, Hartwrightia, Leitneria, Lophiola, Macranthera, Pinckneya, Pyxidanthera, Rhododon, Schwalbea, Sclerolepis, Serenoa, Stokesia, Vaseyochloa, and Zenobia. These genera are sufficiently different from all others of their respective families that they have no living relatives. Two, Dwnaea and Leitneria, represent monotypic families. Some of the 34 monotypic genera may have originated (evolved) in adjacent floristic provinces and have since lost all relatives that inhabited those provinces. Braun (1955) summarized the work of several botanists, who maintained that a t least some genera or species which now chiefly or wholly inhabit the coastal plain may have originated in the Appalachian uplands. Examples are Conradina spp., Croomia pauciflora, Leiophyllum buxifolium, Sarracenia spp., Schwalbea americana, Stewartia malacodendron, T m d i u m spp. We think this scenario highly unlikely for all 34 monotypic genera and suggest that a significant number, perhaps the great majority, evolved in situ within the coastal plain. If any one of the above genera evolved elsewhere, then one might expect evidence to remain in those areas, either in the form of living relatives (closely related genera, species or infraspecific taxa) or in the form of fossilized remains. Yet, neither appears to be the case, according to the available paleobotanical record. 72
CASTANEA VOLUME 66
Further evidence for the antiquity of some segments of the coastal plain flora is provided by Arcto-Tertiary relicts. While the Arcto-Tertiary disjuncts of the Appalachian flora have been well studied and emphasized in the past (Boufford and Spongberg 1983, Li 1952, Wood 1971, Wu 1983),the coastal plain currently harbors numerous such relicts not now present in, or not characteristic of, the Appalachian Floristic Province. Examples include: Aletris, Catalpa, Elliottia, Franklinia, Gelsemium, Gordonia, Helonias, Illicium, Narthecium, Nyssa, Pyxidanthera, Sarracenia, Schisandra, Taxodium, Taxus, Torreya, Wisteria. Much phylogenetic work is needed to resolve issues of speciation and relictualism within the coastal plain.
Refugia and Centers of Speciation From the phytogeographic patterns discussed previously, it is apparent that there are a number of nodes of endemism that have served as refugia or as centers of speciation, or both. These may be summarized as 1) southern New Jersey, 2 ) southeastern North Carolina, 3 ) southern Georgia, 4 ) peninsular Florida, 5 ) the East Gulf Coastal Plain, 6 ) western Louisiana and eastern Texas, 7 ) south Texas and northeast Mexico, and 8 ) subtropical south Florida. Each of these areas supports numerous endemics. Some of these areas also form the basis for bimodal or trimodal distribution patterns, such as New JerseyNorth Carolina, suggesting that they may be as much relictual centers as speciation centers. It may be significant that, with the exception of south Florida, these areas correspond closely to the major geological "arches" in the coastal plain, where sediments are thinner over the basement rock (Hunt 1974, Walker and Coleman 1987). The major arches are the 1 ) South New Jersey Uplift, 2 ) Cape Fear Arch, 3 ) Central Georgia Uplift, 4 ) Ocala Uplift or Peninsular Arch, 5 ) Decatur Arch, 6 ) Sabine Arch, and 7 ) San Marcos Arch. At the present it is unclear how these arches may have contributed to speciation on the coastal plain, since the sequences of uplifting and downwarping have not been fully worked out. Nonetheless, parts of the Peninsula Arch in Florida have been suitable for plant habitation since the late Miocene or early Pliocene (Huck et al. 1989, James 1961) and much of the Cape Fear Arch in the Carolinas has been emersed since the Eocene (Hunt 1974, LeBlond 2001). In addition, soils above several of these arches are notable for being nutrient-poor coarse sands, which may in turn be related to fire frequencies. Recall that the longleaf pine ecosystem (pattern # l a ) ,the core area of endemism within the coastal plain, extends from Virginia to central Florida and east Texas and that its ecology is largely driven by fire and poor soils. As an exercise coastal plain speciation within the framework of the aforementioned arches, we may look at the distributions of the seven species of the endemic genus Carphephorus in the Asteraceae. Referring to the nodes of endemism discussed above, Carphephorus bellidifolius occurs only in #2, C. tomentosus occurs in #2 and 3, C. corymbosus in #3 and 4, C. carnosus in #4, C. pseudoliatris in #5, and C. odoratissimus and C. paniculatus occur in #2, 3, 4, 5. In their mo~ographof the genus, Correa and Wilbur (1969)noted the same striking distribution patterns: "It is perhaps significant and certainly interesting to note that those species that seem most closly related occupy separate geographic areas. Carphephorus corymbosus is found in peninsular Florida north into southeastern Georgia, while the morphologically most similar species, C. bellidifolius, occurs . . . from southeastern Virginia to northeastern Georgia. Carphephorus tomentosus extends . . . from southeastern Virginia into [southeastern] Georgia, while its closest relatives are allopatric: C. pseudoliatris, ranging from . . . southwestern Georgia into eastern Louisiana, and C. carnosus, found only in central peninsular Florida." "Carphephorus odoratissimus and C. paniculatus, which were formerly treated as members of the genus Trilisa, are largely syrnpatric, but the striking differences in inflorescence, pubescence, texture, etc. suggest that their similarities are either the result of convergent evolution or perhaps an indicator of the ancestral condition . . ., and hence they are not so closely related as previously suggested." Future Research As interesting as the Carphephorus example is, there is need for much deeper analyses of these geologic arches and in their role in speciation and phytogeography. The very large number of taxa endemic to the coastal plain constitute a pool of research subjects nearly unparalleled in MARCWJUNE 2001
73
North America; they may be examined individually or collectively in groups (based on shared distributions) to better understand their origins, speciation history, range expansions and contractions, and relictualism. Many questions about coastal plain endemics and the processes of endemism remain. What are the ages of the endemic genera and species? Can we infer rates of evolution from past distributions (Stebbins 1947), DNA analysis, or other methods? Knowing the ages of taxa, what then can we conclude about their origins, spread, and speciation on the coastal plain relative to the timing of geological events? What role did the exposed continental shelf play as a refugium and corridor for plant movements in the mid-Atlantic region during glacial cycles? What other major and minor patterns of distribution exist within the coastal plain? Why are there no endemic taxa in the Black Belt and Jackson Prairies of Alabama and Mississippi? Why do a substantial number of endemics reach central and montane portions of Alabama, but relatively few in Mississippi extend beyond the southern quarter of the state?
Summary In this paper we document high levels of endemism within the Atlantic and Gulf Coastal Plains Floristic Province of North America. Of the nearly 7960 taxa (species, subspecies, varieties) documented on the coastal plain, nearly 6000 are considered native. Of these, 1306 full species (21.8%) and 1603 total taxa (26.7%) are strictly endemic or near-endemic (90% of all occurrences are restricted to the province). Two families and 47 genera are considered endemic or near-endemic to the province-the latter number far beyond any suggested by previous authors. These figures place the Coastal Plain Floristic Province squarely in the front rank of floristic regions in North America for diversity and rates of endemism. Moreover, endemic taxa are widespread throughout the province, from New England to Tamaulipas, Mexico. We describe 27 major and minor patterns of distribution displayed by the endemic taxa; these "centers of endemism" polygons occur throughout the province, suggesting that the processes of speciation has taken place over a very broad front as the coastal plain was influenced by a variety of geological, climatic, and biological events. Patterns range from very small in size, a consequence of specialized local edaphic conditions or of relictualism, to very large, suggesting that some taxa have adapted to a wide range of conditions andlor have managed to disperse across many potential barriers. Far from static, however, these distribution patterns will change over time, as new data necessitate alteration of boundaries and as new patterns are discerned. Even now, herbarium research frequently yields one or more new state records and several range extensions, even in taxa thought to be well-known. Field work throughout the coastal plain, but especially in southern portions, routinely yields new county or state records and even surprising disjuncts (see Ertter 2000 for an overview of recent North American floristic discoveries). The number of undescribed species listed in this paper (8) plus those described in the past 25 years (200+, for most see Hartman and Nelson 1998), suggest that there are many overlooked plants yet to be found, even in this highly altered and fragmented landscape. By overlooked we mean not only new discoveries to science, but also taxa that have been uncritically synonymized in the past. These are indeed exciting times for coastal plain botanists: there is a synergy of many botanical disciplines (ecological research, herbarium studies, field inventory, laboratory research, Heritage Program and government databases, cladistics, etc.) that now make it feasible to not only catalogue alpha diversity, but to ask searching questions about its origins, history, and ecology. APPENDIX 1 Scientific names used in the text, with author citations. Numbers correspond to the distribution patterns treated in the Results section. This is not a complete list of coastal plain endemics, but just those mentioned in this paper. Abronia macrocarpa L.A. Gal. . . . . . . . . . . . . . . 16 Acer rubrum L.var. drummondii (Hook. & Arn. ex Nutt.) Sarg. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Adelia uaseyi (Coult.) Pax & K. Hoffmann . . . . . . . 17 Agalinis acuta Pennell . . . . . . . . . . . . . . . . . . . . 1
74
Agalinis Agalinis Agalinis Agalinis Agalinis
aphylla (Nutt.) Raf. . . . . . . . . . . . . . . . 18
caddoensis Pennell . . . . . . . . . . . . . . . . 14
divaricata (Chapman) Pennell . . . . . . . . 10
harperi Pennell . . . . . . . . . . . . . . . . . . 25
laxa Pennell . . . . . . . . . . . . . . . . . . . . . 6
CASTANEA VOLUME 66
Agalinis linifolia (Nutt.) Britt . . . . . . . . . . . . . . . 24
Agalinis obtusifolia Raf. . . . . . . . . . . . . . . . . . . 22
Agaue decipiens Baker . . . . . . . . . . . . . . . . . . . . 9
Aletris aurea Walt. . . . . . . . . . . . . . . . . . . . . . . 18
Aletris bracteata Northrop . . . . . . . . . . . . . . . . . . 9
Aletris lutea Small . . . . . . . . . . . . . . . . . . . . . . 18
Aletris obouata Nash . . . . . . . . . . . . . . . . . . . . . 6
Allium sp . nov . aff . cernuum Roth . . . . . . . . . . . . . 4
Amorpha georgiana Wilbur var . confusa Wilbur . . . . 4
Amorpha panzculata Torr. & Gray . . . . . . . . . . . 14
Andropogon braehystachyus Chapman . . . . . . . . . . 6
Andropogon capillipes Nash . . . . . . . . . . . . . . . . 25
Andropogon glaucopsis Ell . . . . . . . . . . . . . . . . . 18
Andropogon longiberbis Hack. . . . . . . . . . . . . . . 25
Andropogon mohrii (Hack.) Hack . ex Vasey . . . . . . 18
Andropogon tracyi Nash . . . . . . . . . . . . . . . . . . 18
Andropogon uirginicus L . var . decipiens C . Campbell
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Anthaenantia rufa (Nutt.) Schultes . . . . . . . . . . . 18
Aristida condensata Chapman . . . . . . . . . . . . . . 18
Aristida mohrii Nash . . . . . . . . . . . . . . . . . . . . 13
Aristida simpliciflora Chapman . . . . . . . . . . . . . 13
Aristida spiciformis El1. . . . . . . . . . . . . . . . . . . 24
Aristida stricta Michx . sensu strict0 . . . . . . . . . . . . 4
Arnoglossum album L.C. Anders . . . . . . . . . . . . . 11
Arnoglossum floridanum (Gray) H . Robins . . . . . . . . 6
Asclepias connivens Baldw . . . . . . . . . . . . . . . . . . 6
Aster adnatus Nutt . . . . . . . . . . . . . . . . . . . . . . 25
Aster chapmanii Torr . & Gray . . . . . . . . . . . . . . 12
Aster eryngiifolius T o m. & Gray . . . . . . . . . . . . . 10
Aster reticulatus Pursh . . . . . . . . . . . . . . . . . . . . 6
Aster spinulosus Chapman . . . . . . . . . . . . . . . . 12
Astragalus michauii (Kuntze) F.J. Herm . . . . . . . . 5
Astragalus soxmaniorum Lundell . . . . . . . . . . . . 14
Atriplex kkbergorum M.C. Johnston . . . . . . . . . . 17
Atriplex pentandra (Jacq.) Stand1. . . . . . . . . . . . . 20
Axonopus furcatus (Fluegge) A.S. Hitchc . . . . . . . . 24
Balduina uniflora Nutt . . . . . . . . . . . . . . . . . . . 18
Baptisia arachnifera W . Duncan . . . . . . . . . . . . . . 7
Baptisia calycosa Canby var . calycosa . . . . . . . . . . 7
Baptisia calycosa Canby var . uillosa Canby . . . . . . 12
Baptisia cinerea (Raf.) Fern . & Schub. . . . . . . . . . . 3
Bartonia verna (Michx.) Raf . ex Bart . . . . . . . . . . 18
Bidens mitis (Michx.) Sherff . . . . . . . . . . . . . . . 24
Boerhauia mathisiana F.B. Jones . . . . . . . . . . . . 15
Boltonia apalachicolensis L.C. Anders . . . . . . . . . . 11
Boltonia caroliniana (Walt.) Fern . . . . . . . . . . . . . . 3
Bonamia grandiflora (Gray) Hallier f . . . . . . . . . . . 8
Borrichia frutescens (L.) DC . . . . . . . . . . . . . . . . 25
Bratoria arenaria Lundell . . . . . . . . . . . . . . . . . 17
Brasoria pulcherrima Lundell . . . . . . . . . . . . . . 16
Brunniehia ouata (Walt.) Shinners . . . . . . . . . . . 19
Bulbostylis stenophylla (Ell.) C.B. Clarke . . . . . . . 24
Cakile geniculata (B. Robins.) Millsp . . . . . . . . . . . 15
Cakile lanceolata (Willd.) O.E. Schulz ssp.pseudoconstric-
ta Rodman . . . . . . . . . . . . . . . . . . . . . . 27
Calumovilfa breuipilis (Torr.) Scribn . . . . . . . . . . . . 2
Callisia micrantha (Torr.) D.R. Hunt . . . . . . . . . . 17
Calopogon barbatus (Walt.) Ames . . . . . . . . . . . . 18
Calopogon tuberosus (L.) B.S.P. var . simpsonii (Chapman) Magrath . . . . . . . . . . . . . . . . . . . . . . . . 9
Calydorea coelestina (Bartr.) Godblatt & Henrich . . . 7
Carex baltzellii Chapman ex Dewey . . . . . . . . . . 10
Carex barrattii Schwein . & T o m. . . . . . . . . . . 22, 23
Carex bicknellii Britt . var . opaea F.J. Herm . . . . . . 19
Carex collinsii Nutt . . . . . . . . . . . . . . . . . . . . . . 22
MARCWJUNE 2001
Carex dasycarpa Muhl . . . . . . . . . . . . . . . . . . . . . 6
Carex lutea LeBlond . . . . . . . . . . . . . . . . . . . . . . 4
Carex socialis Mohlenbrock & Schwegm. . . . . . . . 19
Carex turgescens Torr . . . . . . . . . . . . . . . . . . . . 13
Carex uerrucosa Muhl . . . . . . . . . . . . . . . . . . . . 18
Carphephorus bellidifolius (Michx.) Torr . & Gray . . . 3
Carphephorus carnosus (Small) C.W. James . . . . . . 8
Carphephorus corymbosus (Nutt.) Torr . & Gray . . . . 6
Carphephorus odoratissimus (J.F. Gmel) Herbert . . 18
Carphephorus paniculatus (J.F. Gmel.) Herbert . . . 18
Carphephorus pseudoliatris Cass. . . . . . . . . . . . . 10
Carphephorus tomentosus (Michx.) Torr . & Gray . . . 3
Carya floridana Sarg . . . . . . . . . . . . . . . . . . . . . . 8
Catalpa specwsa (Warder) Warder ex Engelm . . . . . 19
Centrosema arenicola (Small) F.J. Herm . . . . . . . . . 8
Ceratiola ericoides Michx . . . . . . . . . . . . . . . . . . 18
Chaetopappa imberbis (Gray) Nesom . . . . . . . . . . 16
Chamaecrista nietitans (L.) Moench var . aspera (Muhl. ex
Ell.) Irwin & Barneby . . . . . . . . . . . . . . . 25
Chamaecyparis thyoides (L.)B.S.P. var . henryae (Li) Little
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chamaesyce deltoidea (Engelm. ex Chapman) Small 9
Chapmannia floridana Torr . & Gray . . . . . . . . . . 18
Chaptalia tomentosa Vent . . . . . . . . . . . . . . . . . 18
Chasmanthium larum (L.) Yates . . . . . . . . . . . . 22
Chasmanthium ornithorhynchum (Steud.) Yates . . . 10
Chromolaena frustrata (B. Robins.) King & H . Robins .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chrysoma pauciflosculosa (Michx.) Greene . . . . . . 18
Chrysopogon pauciflorus (Chapman) Benth . ex Vasey
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Chrysopsis godfreyi Semple . . . . . . . . . . . . . . . . 12
Chrysopsis lanuginosa Small . . . . . . . . . . . . . . . 12
Cleistes bifaria (Fern.) Catling & Gregg . . . . . . . . 26
Cleistes diuaricata (L.) Ames . . . . . . . . . . . . . . . . 2
Clethra alnifolia L . var . alnifolia . . . . . . . . . . 20, 22
Cliftonia monophylla (Lam.) Britt . ex Sarg . . . . . . . 18
Clitoria fragrans Small . . . . . . . . . . . . . . . . . . . . 8
Coelorachis tessellata (Steud.) Nash . . . . . . . . . . . 10
Conradina etonia Kral & McCartney . . . . . . . . . . . 7
Cooperia traubii Hayward . . . . . . . . . . . . . . . . . 1 5
Coreopsis falcata Boynt. . . . . . . . . . . . . . . . . . . . 3
Coreopsis linifolia Nutt . . . . . . . . . . . . . . . . . . . 18
Coreopsis nuecensis Heller . . . . . . . . . . . . . . . . . 16
Coreopsis rosea Nutt . . . . . . . . . . . . . . . . . . . . . 20
Coryphantha maeromeris (Engelm.) Lem . var . runyonii
(Britt . & Rose) Benson . . . . . . . . . . . . . . 17
Crataegus chrysocarpa Ashe var . bicknellii (Eggleston)
Palmer . . . . . . . . . . . . . . . . . . . . . . . . . 1
Crataegus marshallii Egglest . . . . . . . . . . . . . . . 19
Crataegus nananixonii Phipps & O'Kennon . . . . . . 16
Croomia pauciflora (Nutt.) Torr .
Crossopetalum ilicifolium (Poir.) Kuntze . . . . . . . . . 9
Croton glandulosus L . var . floridanus (Ferguson) R.W.
Long . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Croton glandulosus L. var . pubentissimus Croizat . . 27
Ctenium aromatzum (Walt.) Wood . . . . . . . . . . . 18
Ctenium floridanum ( A S. Hitchc.) A.S. Hitchc . . . . . 7
Cucurbita okeechobeensis (Small) Bailey var . okeechobeen-
sis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
C u p h a aspera Chapman . . . . . . . . . . . . . . . . . 11
Cuscuta runyonii Yuncker . . . . . . . . . . . . . . . . . 17
Cyperus distinctus Steud. . . . . . . . . . . . . . . . . . 25
Cyperus ouatus Baldw . . . . . . . . . . . . . . . . . . . . 24
Dalea pinnata (J.F. Gmel.) Barneby . . . . . . . . . . 18
Deeringothamnus rugelii (B. Robins.) Small . . . . . . 7
Desmodium floridanum Chapman . . . . . . . . . . . . . 6
Desmodium tenuifolium Torr. & Gray . . . . . . . . . 18
Dicerandra cornutissima R . Huck . . . . . . . . . . . . . 8
Dicerandra frutescens Shinners . . . . . . . . . . . . . . 8
Dicerandra odoratissima Harper . . . . . . . . . . . . . . 6
Dicerandra radfordiana R . Huck . . . . . . . . . . . . . . 7
Dichanthelium ensifolium (Baldw. ex Ell.) Gould var . breve
( A. Hitchc. & Chase) B . Hansen & Wunderlin . . 8
Dichanthelium erectifolium (Nash)Gould & Clark . . . 24
Dichanthelium hirstii (Swallen)Kartesz . . . . . . . . . 2
Dichanthelium wrightianum (Scribn.) Freckmann . . 24
Digitaria cognata (Schultes)Pilger var . arenicola
(Swallen)R . Webster . . . . . . . . . . . . . . . 15
Digitaria pauciflora A.S. Hitchc . . . . . . . . . . . . . . . 9
Digitaria serotina (Walt.) Michx . . . . . . . . . . . . . . 24
Digitario texana A.S. Hitchc . . . . . . . . . . . . . . . . 27
Dionaea muscipula Ellis . . . . . . . . . . . . . . . . . . . 4
Dioscorea floridana Bartlett . . . . . . . . . . . . . . . . . 6
Drosera filiformis Raf. . . . . . . . . . . . . . . . . . . . 20
Drosera tracyi Macfarlane . . . . . . . . . . . . . . . . . 10
Dyschoriste angusta (Gray)Small . . . . . . . . . . . . . 9
Dyschoriste humistrata (Michx.) Kuntze . . . . . . . . . 6
Echinacea sanguinea Nutt . . . . . . . . . . . . . . . . . 14
Echinodorus floridanus Haynes & Burkhalter . . . . 12
Echinodorus paruulus Engelm . . . . . . . . . . . . . . . 24
Eleocharis austrotexana M.C. Johnston . . . . . . . . 17
Eleocharis melanocarpa Torr . . . . . . . . . . . . . . 21, 23
Eleocharis microcarpa Torr . var . microcarpa . . . . . 24
Eleocharis tortilis (Link) Schultes . . . . . . . . . . . . 22
Eleocharis tricostata Torr . . . . . . . . . . . . . . . . . . 2 1
Eleocharis tuberculosa (Michx.) Roemer & Schultes
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Elytraria caroliniensis (J.F. Gmel.) Pers .
var . caroliniensis . . . . . . . . . . . . . . . . . . . 6
Encyclia tampensis (Lindl.) Small . . . . . . . . . . . . 25
Erechtites hieraciifolia ( L . )Raf. ex DC . var . megalocarpa
(Fern.) Cronq. . . . . . . . . . . . . . . . . . . . . . 1
Erigeron quercifo1iuLa.m. . . . . . . . . . . . . . . . . . 25
Erigeron uernus ( L . )Torr . & Gray . . . . . . . . . . . . 18
Erwcaulon nigrobracteatum Bridges & Orzell . . . . 11
Erwcaulon t m n s e Koern . . . . . . . . . . . . . . . . . . 13
Erwchloa michauxii (Poir.) A.S. Hitchc . var . michawii
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Erwgonum tomentosum Michx . . . . . . . . . . . . . . . 18
Eryngium cuneifolium Small . . . . . . . . . . . . . . . . 8
Eupatorium dubium Willd . ex Poir . . . . . . . . . . . . 20
Eupatorium glaucescens Ell . . . . . . . . . . . . . . . . . 18
Eupatorium leucolepis (DC.) Torr . & Gray var . leucolepis
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Eupatorium leucolepis (DC.)Torrey & Gray
var . nouae-angliae Fern . . . . . . . . . . . . . . . 1
Eupatorium resinosum T o m. ex DC . . . . . . . . . . . 2
Eupatorium semiserratum DC . . . . . . . . . . . . . . . 19
Euphorbia floridnna Chapman . . . . . . . . . . . . . . 10
Euphorbia innocua L.C. Wheeler . . . . . . . . . . . . 15
Euphorbia telephwides Chapman . . . . . . . . . . . . 11
Euoluulus grisebachii Peter . . . . . . . . . . . . . . . . . 9
Fimbristylis perpusilla Harper ex Small & Britt . . . 22
Forestiera godfreyi L.C. Anders . . . . . . . . . . . . . . . 6
Frankenia johnstonii Correll . . . . . . . . . . . . . . . 17
Franklinia alatamaha Bartr . ex Marsh . . . . . . . . . . 7
Fuirena pumila (Tom.) Spreng . . . . . . . . . . . . . . . 2 1
Fuirena scirpoidea Michx . . . . . . . . . . . . . . . . . . 24
Galactia ellwttii Nutt . . . . . . . . . . . . . . . . . . . . . 6
Galactia pinetorum Small . . . . . . . . . . . . . . . . . . 9
Garberia heterophylla (Bartr.) Merr . & F . Harper . . . 8
Gaura demareei Raven & Gregory . . . . . . . . . . . . 14 Gaylussacia dumosa (Andr.) Torr . & Gray var . bigelouiana Fern . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Gaylussacia mosieri Small . . . . . . . . . . . . . . . . . 10
Gentiana autumnalis L . . . . . . . . . . . . . . . . . . . . 2
Gentiana pennelliana Fern . . . . . . . . . . . . . . . . . 11
Gilia ludens Shinners . . . . . . . . . . . . . . . . . . . . 17
Glyceria arkansana Fern . . . . . . . . . . . . . . . . . . 19
Glyceria obtusa (Muhl.)Trin . . . . . . . . . . . . . . 20, 23
Grindelia oolepis Blake . . . . . . . . . . . . . . . . . . . 17
Halesia diptera Ellis var . diptera . . . . . . . . . . . . . 6
Harperocallis flaw McDaniel . . . . . . . . . . . . . . . 11
Harrisia aboriginum Small . . . . . . . . . . . . . . . . . 9
Hartwrightia floridana Gray ex S . Wats. . . . . . . . . 7
Hedyotis nigricans (Lam.) Fosberg var . puluinata (Small)
Fosberg . . . . . . . . . . . . . . . . . . . . . . . . . 7
Helianthemum arenicola Chapman . . . . . . . . . . . 10
Helianthemum carolinianum (Walt.) Michx . . . . . . 18
Helianthemum dumosum (Bickn.) Fern . . . . . . . . . . 1
Helianthus carnosus Small . . . . . . . . . . . . . . . . . 7
Helonias bullata L . . . . . . . . . . . . . . . . . . . . . . 26
Herbertia lahue (Molina)Goldblatt
Houstonia correllii (W. Lewis) Correll . . . . . . . . . 17
Houstonia croftiae Britt . & Rusby . . . . . . . . . . . . 17
Houstonia procumberzs (Walt . ex J.F. Gmel.) Standl . . . . 6
Hydrolea corymbosa J.F. Macbr . ex Ell . . . . . . . . . . 6
Hydrolea ouata Nutt . ex Choisy . . . . . . . . . . . . . 19
Hymenocallisgalwstonensis(Herbert) Baker . . . . . 15
Hymenocallis latifolia (P. Mill.) M . Roemer . . . . . . 25
Hymenopappus carrizoanus B.L. Turner . . . . . . . . 16
Hymenoxys texana (Coult. & Rose) Cockerel1 . . . . . 15
Hypericum chapmanii P . Adams . . . . . . . . . . . . . 10
Hypericum cumulicola (Small) P . Adams . . . . . . . . 8
Hypericum exile P. Adams . . . . . . . . . . . . . . . . . 10
Hypericum lissophloeus P . Adams . . . . . . . . . . . . 12
Hypericum setosum L . . . . . . . . . . . . . . . . . . . . 18
Hypericum sp . nov . a f f. brachyphyllum (Spach)Steud .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Hypericum tetrapetalum Lam . . . . . . . . . . . . . . . 24
Hypoxis juncea S m . . . . . . . . . . . . . . . . . . . . . . 24
Ilex glabra (L.)Gray . . . . . . . . . . . . . . . . . . . . 20
I& opaca Aiton var . arenicola (Ashe)Ashe . . . . . . . 8
Iris prismatica Pursh ex Ker.Gaw1 . . . . . . . . . . 20, 22
Isoetes louisianensis Thieret . . . . . . . . . . . . . . . . 10
Isoetes microvela D.F. Brunton . . . . . . . . . . . . . . . 4
lua frutescens L . ssp . oraria (Bartlett)R.C. Jackson
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Jacquemontia curtissii Peter ex Small . . . . . . . . . . 9
Juncus caesariensis Coville . . . . . . . . . . . . . . 20, 26
Juncus ellwttii Chapman . . . . . . . . . . . . . . . . . 22
Juncus gymnocarpus Coville . . . . . . . . . . . . . . . 26
Juncus repens Michx . . . . . . . . . . . . . . . . . . . . . 24
Juncus roemerianus Scheele . . . . . . . . . . . . . . . . 25
Juncus trigonocarpus Steud . . . . . . . . . . . . . . . . 18
Juticia crassifilia (Chapman)Chapman ex Small . . . 11
Justicia runyonii Small . . . . . . . . . . . . . . . . . . . 17
Kalmia cuneata Michx . . . . . . . . . . . . . . . . . . . . . 4
Kalmia hirsuta Walt. . . . . . . . . . . . . . . . . . . . . . 6
Kosteletzkya uirginica (L.) K . Presl ex Gray . . . . . . 24
Lachnanthes caroliniana (Lam.)Dandy 20, 22, 23, 24
Lachnocaulon anceps (Walt.) Morong . . . . . . . . . . 24
Lachnocaulon engleri Ruhl . . . . . . . . . . . . . . . . . 24
Lantana depressa Small var . floridnna (Moldenke)
R . Sanders . . . . . . . . . . . . . . . . . . . . . . . 9
Lechea lakelae Wilbur . . . . . . . . . . . . . . . . . . . . . 9
Leiophyllum bwifolium (Berg.) El1. . . . . . . . . . . . 26
CASTANEA VOLUME 66
Lenophyllum texanum (J.G. Sm.) Rose . . . . . . . . . 15
Lespedeza angustifolia (Pursh) Ell . . . . . . . . . . . . 22
Lesquerella angustifolia (Nutt. ex Torr . & Gray) S . Wats.
.................................. 14
Lesquerella lindheimeri (Gray)S Wats. . . . . . . . . 15
Lesquerella thamnophila Rollins & Shaw . . . . . . . 17
Leucothoe axillaris (Lam.)D . Don . . . . . . . . . . . . 18
Liatris acidota Engelm . & Gray . . . . . . . . . . . . . 14
Liatris chapmanii Torr . & Gray . . . . . . . . . . . . . 10
Liatris cokeri Pyne & Stucky . . . . . . . . . . . . . . . . 5
Liatris cymosa (H. Ness) K . Schum . . . . . . . . . . . . 14
Liatris garberi Gray . . . . . . . . . . . . . . . . . . . . . 25
Liatris ohlingerae (Blake)B . Robins . . . . . . . . . . . . 8
Liatris provincialis Godfrey . . . . . . . . . . . . . . . . 11
Licania michauxii Prance . . . . . . . . . . . . . . . . . 18
Lilaeopsis chinensis (L.) Kuntze . . . . . . . . . . . . . 20
Lilium catesbaei Walt. . . . . . . . . . . . . . . . . . . . 18
Lilium iridollae Henry . . . . . . . . . . . . . . . . . . . 12
Lilium sp . nov . a f f. iridollae Henry . . . . . . . . . . . . 3
Lindera melissifolia (Walt.)Blume . . . . . . . . . . . 19
Lindera subcoriacea E . Wofford . . . . . . . . . . . . . 18
Linum arenicola (Small)Wink1. . . . . . . . . . . . . . . 9
Linum carteri Small . . . . . . . . . . . . . . . . . . . . . . 9
Linum floridanum (Planch.) Trel . var . floridanum . . 18
Lipocarpha maculata (Michx.) Torr. . . . . . . . . . . 21
Lobelia batsonii B . Pittman ined . . . . . . . . . . . . . . 5
Lobelia bqvkinii Torr . & Gray ex DC . . . . . . . . . . . . 2
Lobelia canbyi Gray . . . . . . . . . . . . . . . . . . . . . . 2
Lophwla aurea Ker.Gaw1 . . . . . . . . . . . . . . 2, 13, 20
Ludwigia arcuata Walt. . . . . . . . . . . . . . . . . . . . 6
Ludwigia hirtella Raf. . . . . . . . . . . . . . . . . . . . 22
Ludwigia pilosa Walt. . . . . . . . . . . . . . . . . . . . 18
Ludwigia sphaerocarpa Ell . . . . . . . . . . . . . . . . . 21
Lupinus westianus Small var . westianus . . . . . . . . 12
Lycium carolinianum Walt. var . carolinianum . . . . 24
Lycopodiella alopecuroides (L.) Cranfill . . . . . . . . . 24
Lycopus amplectens Raf. . . . . . . . . . . . . . . . . . . 21
Lycopus cokeri Ahles ex Sorrie . . . . . . . . . . . . . . . 5
Lyonia ferruginea (Walt.)Nutt . . . . . . . . . . . . . . . . 6
Lyonia lucida (Lam.) K . Koch . . . . . . . . . . . . . . . 24
Lysimachia asperulifolia Poir . . . . . . . . . . . . . . . . 4
Lysimachia loomisii T o m. . . . . . . . . . . . . . . . . . . 4
Lysimachia radicans Hook . . . . . . . . . . . . . . . . . 19
Lythrum lineare L . . . . . . . . . . . . . . . . . . . . . . . 24
Macbridea alba Chapman . . . . . . . . . . . . . . . . . 11
Macbridea caroliniana (Walt.) Blake . . . . . . . . . . 18
Machaeranthera phyllocephala (DC.) Shinners . . . . 27
Macranthera flammea (Bartr.) Pennell . . . . . . . . . 10
Magnolia ashei Weatherby . . . . . . . . . . . . . . . . 12
Magnolia grandiflora L . . . . . . . . . . . . . . . . . . . 18
Magnolia virginiana L . . . . . . . . . . . . . . . . . . . . 23
Manfreda longiflora (Rose)Verhoek-Williams . . . . 17
Manihot walkerae Croizat . . . . . . . . . . . . . . . . . 17
Marshallia graminifolia (Walt.) Small ssp . graminifolia
................................... 3
Matelea paruiflora (Torr.) Woods. . . . . . . . . . . . . 17
Melampyrum lineare Desr . var . pectinatum (Pennell)
Fern . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Melanthera parvifolia Small . . . . . . . . . . . . . . . . . 9
Mentzelia floridana Nutt . ex Torr. & Gray . . . . . . 25
Mespilus canescens Phipps . . . . . . . . . . . . . . . . . 19
Mitreola sessilifolia (J.F. Gmel.) G . Don . . . . . . . . 25
Monarda uiridissima Correll . . . . . . . . . . . . . . . 16
Muhlenbergia torreyana (Schultes) A.S. Hitchc . . . . 22
Narthecium americanum Ker.Gaw1 . . . . . . . . . . . 2, 26
Nolina brittoniana Nash . . . . . . . . . . . . . . . . . . . 8
MARCWJUNE 2001
Nolina georgiana Michx . . . . . . . . . . . . . . . . . . . 18
Nuphar sagittifolia (Walt.) Pursh . . . . . . . . . . . . . 3
Nuphar uluacea Mill . & Stand1. . . . . . . . . . . . . . 12
Nyssa aquatica L . . . . . . . . . . . . . . . . . . . . . . . 19
Nyssa ogeche Bartr . ex Marsh . . . . . . . . . . . . . . . . 6
Nyssa ursina Small . . . . . . . . . . . . . . . . . . . . . 11
Oenothera humifusa Nutt . . . . . . . . . . . . . . . . . . 24
Oenothera riparia Nutt . . . . . . . . . . . . . . . . . . . . 3
Opuntia corallicola Small . . . . . . . . . . . . . . . . . . 9
Orbexilum uirgatum (Nutt.) Rydb . . . . . . . . . . . . . . 7
Oxalis berlandieri Tom. . . . . . . . . . . . . . . . . . . 17
Oxypolis filiformis (Walt.) Britt . ssp .greenmanii (Mathias
& Constance) Judd . . . . . . . . . . . . . . . . . 12
Palafoxia feayi Gray . . . . . . . . . . . . . . . . . . . . . . 6
Palafoxia hookeriana Torr. & Gray var . minor Shinners
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Panicum brachyanthum Steud . . . . . . . . . . . . . . . 14
Panicum chamaelonche Trin. . . . . . . . . . . . . . . . 24
Panicum dichotomiflorum Michx . var . puritanorum Svens .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Panicum hemitomon Schultes . . . . . . . . . . . . . . . 23
Panicum nudicaule Vasey . . . . . . . . . . . . . . . . . 10
Panicum uirgatum L . var . cubense Griseb. . . . . . . 24
Paronychia americana (Nutt.) Fenzl ex Walp.
ssp . americana . . . . . . . . . . . . . . . . . . . . 6
Paronychia chartacea Fern . ssp . minima L.C. Anders .
.................................. 12
Paronychia lundellorum B.L. Turner . . . . . . . . . . 17
Paronychia setacea Torr. & Gray . . . . . . . . . . . . . 16
Parthenium integrifolium L . var . mabryawm Mears . . . 3
Paspalum monostachyum Vasey . . . . . . . . . . . . . 27
Paspalum setaceum Michx . var . psammophilum (Nash)
D . Banks . . . . . . . . . . . . . . . . . . . . . . . . 1
Pedwmelum hypogaeum (Nutt. ex T o m. & Gray) Rydb .
var . subulatum (Bush)J . Grimes . . . . . . . . 14
Persea humilis Nash . . . . . . . . . . . . . . . . . . . . . 8
Persea palustris (Raf.) Sarg . . . . . . . . . . . . . . . . . 25
Phanopyrum gymnocarpon (Ell.) Nash . . . . . . . . . 19
Phoebanthus grandiflorus (Torr. & Gray) Blake . . . 18
Phoebanthus tenuifolius (Torr. & Gray) Blake . . . . 11
Physalis lanceolata Michx . . . . . . . . . . . . . . . . . . . 5
Physostegia godfreyi Cantino . . . . . . . . . . . . . . . 11
Physostegia longisepala Cantino . . . . . . . . . . . . . 14
Pieris phillyreifolia (Hook.) DC . . . . . . . . . . . . . . . 6
Piloblephis rigida (Bartr. ex Benth.) Raf. . . . . . . . 18
Pinckneya bracteata (Bartr.) Raf. . . . . . . . . . . . . . . 6
Pinguicula ionantha Godfrey . . . . . . . . . . . . . . . 11
Pinguicula primuliflora C . Wood & Godfrey . . . . . 10
Pinguicula pumila Michx . . . . . . . . . . . . . . . . . . 25
Pinus ellwttii Engelm . var . elliottii . . . . . . . . . . . . 6
Pinus palustris P. Mill . . . . . . . . . . . . . . . . . . . . 18
Pityopsis falcata (Pursh)Nutt . . . . . . . . . . . . . . . . 1
Planera aquatica J.F. Gmel . . . . . . . . . . . . . . . . . 19
Platanthera flava (L.) Lindl . var . flaua . . . . . . . . . 20
Platanthera integra (Nutt.) Gray ex Beck . . . . . . 2, 22
Platanthera niuea (Nutt.) Luer . . . . . . . . . . . . . 2, 22
Pleea tenuifolia Michx . . . . . . . . . . . . . . . . . . . . 18
Polanisia erosa (Nutt.)Iltis ssp . erosa . . . . . . . . . 14
Polygala balduinii Nutt . var . carteri (Small) R.R. S m . &
Ward . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Polygala chapmanii Torr . & Gray . . . . . . . . . . . . 10
Polygala cymosa Walt. . . . . . . . . . . . . . . . . . . . . 2
Polygala hookeri Tom. & Gray . . . . . . . . . . . . . . 13
Polygala lewtonii Small . . . . . . . . . . . . . . . . . . . . 8
Polygala smallii R.R. S m . & Ward . . . . . . . . . . . . 9
Polygonella macrophylla Small . . . . . . . . . . . . . . 12
Polygonella myrwphylla (Small) Horton . . . . . . . . . 8
Polygonella parksii Cory . . . . . . . . . . . . . . . . . . 16
Polygonella polygama (Vent.) Engelm . & Gray . . . . 18
Polygonum pensylwnicum L . var. nesophilum Fern. . . . 1
Polygonum puritanorum Fern . . . . . . . . . . . . . . . . 1
Potamogeton floridanus Small . . . . . . . . . . . . . . 12
Proserpinaca pectinata Lam . . . . . . . . . . . 21, 22, 24
Prunus geniculata Harper . . . . . . . . . . . . . . . . . . 8
Pteroglossaspis ecristata (Fern.) Rolfe . . . . . . . . . 24
Ptilimnium sp . nov . a f f. capillaceum (Michx.)Raf. . . 3
Pycnanthemum nudum Nutt . . . . . . . . . . . . . . . . . 6
Pyxidanthera barbulata Michx . sensu lato . . . . . . . . 2
Pyxidanthera barbulata Michx . var . breuifolia (Wells)
Ahles . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Quercus chapmanii Sarg . . . . . . . . . . . . . . . . . . . 6
Quercus hemisphaerica Bartr . ex Willd . . . . . . . . . 18
Quercus inopina Ashe . . . . . . . . . . . . . . . . . . . . . 8
Quercus laeuis Walt. . . . . . . . . . . . . . . . . . . . . . 18
Quercus pagoda Raf. . . . . . . . . . . . . . . . . . . . . 19
Reimarochloa oligostachya (Munro ex Benth.) A.S. Hitchc .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Rhapidophyllum hystrix (Pursh) H . Wend1. & Drude ex
Drude . . . . . . . . . . . . . . . . . . . . . . . . . 18
Rhezia alifanus Walt. . . . . . . . . . . . . . . . . . . . . 18
Rhexia lutea Walt. . . . . . . . . . . . . . . . . . . . . . . 18
Rhezia salicifolia Kral & Bostick . . . . . . . . . . . . 12
Rhododon angulatus (Tharp)B.L. Turner . . . . . . . 15
Rhododon ciliatus (Benth.)Epling . . . . . . . . . . . . 16
Rhynchosia difformis (Ell.) DC . . . . . . . . . . . . . 18, 22
Rhynchospora careyana Fern . . . . . . . . . . . . . . . . . 2
Rhynchospora cephalantha Gray var . microcephala
(Britt.) Kukenth . . . . . . . . . . . . . . . . . . . 24
Rhynchospora chalarocephala Fern . & Gale . . . . . . 22
Rhynchospora crinipes Gale . . . . . . . . . . . . . . . . 13
Rhynchospora curtissii Britt . . . . . . . . . . . . . . . . 10
Rhynchospora debilis Gale . . . . . . . . . . . . . . . . . 18
Rhynchospora glomerata (L.)Vahl var . angusta Gale
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Rhynchospora grayi Kunth . . . . . . . . . . . . . . . . 24
Rhynchospora knieskernii Carey . . . . . . . . . . . . . . 1
Rhynchospora latifolia (Baldw. ex Ell.) Thomas 18, 22
Rhynchospora leptocarpa (Chapman ex Britt.) Small
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Rhynchospora macra (C.B. Clarke) Small . . . . . . . 13
Rhynchospora oligantha Gray . . . . . . . . . . . . . 2, 13
Rhynchospora pallida M.A. Curtis . . . . . . . . . . . . . 2
Rhynchospora pleiantha (Kukenth.) Gale . . . . . 13, 24
Rhynchospora punctata Ell . . . . . . . . . . . . . . . . . . 7
Rhynchospora scirpoides (Torr.)Gray . . . . . . . . . . 21
Rhynchospora wrightiana Boeckl . . . . . . . . . . . . . 24
Rudbeckia graminifolia (Torr. & Gray) C . Boynt . &
Beadle . . . . . . . . . . . . . . . . . . . . . . . . . 11
Rudbeckia texana (Perdue) Cox & Urbatsch . . . . . 14
Sabatia arenicola Greenm. . . . . . . . . . . . . . . . . 15
Sabatia bartramii Wilbur . . . . . . . . . . . . . . . . . . 6
Sabatia calycina (Lam.) Heller . . . . . . . . . . . . . . 24
Sabatia gentianoides Ell . . . . . . . . . . . . . . . . . . . 18
Sabatia grandiflora (Gray)Small . . . . . . . . . . . . 24
Sabatia knnedyana Fern . . . . . . . . . . . . . . . . . . 20
Saccharum baldwinii Spreng . . . . . . . . . . . . . . . 19
Sagittaria papillosa Buch . . . . . . . . . . . . . . . . . . 14
Sagittaria teres S . Wats. . . . . . . . . . . . . . . . . . . . 1
Samolus ebracteatus Kunth var . alyssoides (Heller) R .
Knuth . . . . . . . . . . . . . . . . . . . . . . . . . 1 5
Sarracenia leucophylla Raf. . . . . . . . . . . . . . . . . 10
Schizachyrium maritimum (Chapman)Nash . . . . . 10
Schizachyrium sericatum (Swallen) Gould . . . . . . . . 9
Schwalbea americana L . . . . . . . . . . . . . . . . . . . 22
Scirpus longii Fern . . . . . . . . . . . . . . . . . . . . . . 20
Scleria baldwinii (Torr.) Steud . . . . . . . . . . . . . . 25
Scleria reticularis Michx . sensu stricto . . . . . . . . . 21
Scleria sp . nov . a f f. ciliata Michx . . . . . . . . . . . . . . 4
Sclerolepis uniflora (Walt.)B.S.P. . . . . . . . . . . . . . 2
Scutellaria cardiophylla Engelm . & Gray . . . . . . . 14
Scutellaria floridana Chapman . . . . . . . . . . . . . . 11
Scutellaria glabriuscula Fern . . . . . . . . . . . . . . . 12
Selaginella eatonii Hieron . ex Small . . . . . . . . . 9, 25
Serenoa repens (Bartr.) Small . . . . . . . . . . . . . . . . 6
Sesuuium trianthemoides Correll . . . . . . . . . . . . 15
Setaria corrugata (Ell.) Schultes . . . . . . . . . . . . . 24
Seymeria cassioides (J.F. Gmel.) Blake . . . . . . . . . 25
Sisyrinchium arenicola Bickn . sensu stricto . . . . . 1, 20
Sisyrinchium nashii Bickn . . . . . . . . . . . . . . . . . 25
Solidago latissimifolia P . Mill . . . . . . . . . . . . . . . 20
Solidago patula Muhl . ex Willd . var . strictula Torr . &
Gray . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Solidago pulchra Small . . . . . . . . . . . . . . . . . . . . 4
Solidago uillosicarpa LeBlond . . . . . . . . . . . . . . . 4
Solidago stricta Ait . . . . . . . . . . . . . . . . . . . . . . 24
Solidago uerna M.A. Curtis . . . . . . . . . . . . . . . . . 4
Sorghastrum apalachicolense D . Hall . . . . . . . . . . 10
Sorghastrum secundum (Ell.)Nash . . . . . . . . . . . . 6
Spartina bakeri Merr . . . . . . . . . . . . . . . . . . . . . 6
Spermacoce floridana Urban . . . . . . . . . . . . . . 9 , 27
Spermacoce terminalis (Small) Kartesz & Gandhi . . . 9
Spigelia gentianoides Chapman ex A . DC .
var . gentianoides . . . . . . . . . . . . . . . . . . 11
Spigelia loganwides (Torr. & Gray ex End1. & Fenzl)
A.DC . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Sporobolus floridanus Chapman . . . . . . . . . . . . . . 6
Sporobolus pinetorum A . Weakley & P . Peterson . . . 3
Sporobolus silueanus Swallen . . . . . . . . . . . . . . . 14
Sporobolus tharpii A.S. Hitchc . . . . . . . . . . . . . . . 15
Stachydeoma graueolens (Chapman ex Gray) Small 10
Stachys drummondii Benth . . . . . . . . . . . . . . . . . 17
Stachys hyssopifolia Michx . var . hyssopifolia . . . . . 23
Stewartia malacodendron L .
Stillingia syluatica Garden ex L . ssp . tenuis (Small) D .
Rogers . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Stipulicida setacea Michx . . . . . . . . . . . . . . . . . . 18
Stokesia laeuis (Hill)Greene . . . . . . . . . . . . . . . 18
Stylisma abdita Myint . . . . . . . . . . . . . . . . . . . . 8
Stylisma aquatica (Walt.) Raf. . . . . . . . . . . . . . . 18
Stylisma pickeringii (Torr. ex M.A. Curtis) Gray
var . pickeringii . . . . . . . . . . . . . . . . . . . . 2
Stylisma uillosa (Nash)House . . . . . . . . . . . . . . 27
Stylodon carneus (Medik.)Moldenke . . . . . . . . . . 18
Taxodium distichum (L.) L.C. Rich . . . . . . . . . . . 19
Tazus floridana Nutt . ex Chapman . . . . . . . . . . . 11
Tephrosia chrysophylla Pursh . . . . . . . . . . . . . . . 24
Tetragonotheca ludouiciana (Torr. & Gray) Gray ex Hall
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Thalia dealbata Fraser . . . . . . . . . . . . . . . . . . . 19
Thalictrum cooleyi Ahles . . . . . . . . . . . . . . . . . . . 4
Thelesperma flauodiscum (Shinners)B.L. Turner . . 16
Thelesperma nuecense B.L. Turner . . . . . . . . . . . 17
Thelypodiopsis shinnersii (M.C. Johnston) Rollins . . 17
Thelypteris hispidula (Dcne.)C.F. Reed var . uersicolor
( R. St . John) Lellinger . . . . . . . . . . . . . . 24
Thelypteris ouata R . St . John var . ouata . . . . . . . . 25
Thurouia triflora Rose . . . . . . . . . . . . . . . . . . . 15
Tofieldia glabra Nutt . . . . . . . . . . . . . . . . . . . . . . 4
CASTANEA VOLUME 66
Tofieldia racemosa (Walt.) B.S.P. . . . . . . . . . . . . . 22
Torreya tcucifolia Arn. . . . . . . . . . . . . . . . . . . . . 11
Tradescantia roseolens Small . . . . . . . . . . . . . . . . 6
Tragia scucicola Small . . . . . . . . . . . . . . . . . . . . . 9
Trepocarpw aethusae Nutt. ex DC. . . . . . . . . . . . 19
Trichoneura elegans Swallen . . . . . . . . . . . . . . . 17
Trichostema sp. nov. a f f .dichotomum L. . . . . . . . . . 4
Tridens carolinianus (Steud.) Henr. . . . . . . . . . . . 13
Trillium gracile J. Freeman . . . . . . . . . . . . . . . . 14
Tripsacum floridanurn Porter ex Vasey . . . . . . . 9, 24
Utricularia striata LeConte ex Torr. . . . . . . . . . . 23
Vaccinium crassifolium Andr. ssp. crassifolium . . . . 3
Vaccinium crassifolium Andr. ssp. semperuirens . . . . 5
Vaseyochloa multineruosa (Vasey)A.S. Hitchc. . . . . 15
Verbesina chapmanii J.R. Coleman . . . . . . . . . . . 11
Verbesina heterophylla (Chapman)Gray . . . . . . . . . 7
Verbesina uirginica L. var. laciniata (Poir.) Gray . . . 6
Vernonia blodgettii Small . . . . . . . . . . . . . . . . 9 , 25
Viburnum dentaturn L. var. wnosum (Britt.) Gleason . . 1
Viburnum nudum L. var. nudum . . . . . . . . . . . . 23
Vicia acutifolia Ell. . . . . . . . . . . . . . . . . . . . . . 24
Warea sessilifolia Nash . . . . . . . . . . . . . . . . . . . 10
Xerophyllum asphodeloides (L.)Nutt. . . . . . . . . . . 26
Xylothamia palmeri (Gray)Nesom . . . . . . . . . . . 17
Xyris caroliniana Walt. . . . . . . . . . . . . . . . . . . . 24
Xyris chapmanii Bridges & Orzell . . . . . . . . . . . . 13
Xyris fimbriata Ell. . . . . . . . . . . . . . . . . . . . . 2, 22
Xyris isoetifolia Kral . . . . . . . . . . . . . . . . . . . . 12
Xyris longisepala Kral . . . . . . . . . . . . . . . . . . . 12
Xyris scabrifolia Harper . . . . . . . . . . . . . . . . . . 13
Yucca louisianensis Trel. . . . . . . . . . . . . . . . . . . 14
Zenobia puluerulenta (Bartr. ex Willd.) Pollard . . . . 3
Zephyranthes refugiensis F.B. Jones . . . . . . . . . . 15
Zephyranthes sp. nov. a f f .simpsonii Chapman . . . . . 4
Zigadenus leimanthoides Gray . . . . . . . . . . . . . . 26
Ziziphus celata Judd & Hall . . . . . . . . . . . . . . . . 8
ACKNOWLEDGMENTS We wish to acknowledge the many botanists who have gone before us and who have collected the specimens upon which this paper is based. Curators of the following herbaria kindly provided access to their holdings: AMES, AUA, bas (pers. herb. Bruce Sorrie), ctb (pers. herb. Charles Bryson), DUKE, FLAS, FSU, GA, GH, IBE, LSU, MISSA, Mississippi Museum of Natural Science, NCSC, NCU, NLU, rjl (pers. herb. Richard LeBlond), US, USA, USCH, SWSL, VSC, and VDB (at BRIT). The following provided distribution data or phytogeographic viewpoints: Loran Anderson, Dave Boufford, Charles Bryson, Bill Carr, Linda Chafin, George Gann, Robert Godfrey, Phil Hyatt, John Kartesz, Keith Clancey, Robert Kral, Chris Ludwig, Jim Massey, Sidney McDaniel, John McDonald, Patrick McMillan, Rogers McVaugh, Guy Nesom, Tom Patrick, Bob Peet, Bert Pittman, Jackie Poole, Richard Porcher, Tony Reznicek, A1 Schotz, John Schwegmann, Latimore Smith, David Snyder, Ron Wieland, Bob Wilbur, Carroll Wood, Jr., and Richard Wunderlin. Kancheepuram Gandhi solved several nomenclatural problems and provided scarce reference material. John Prince of the Association for Biodiversity Information prepared the maps. Dan Austin, Richard LeBlond, Carl Nordman, Milo Pyne, Mike Schafale, and Zack Murrell improved earlier versions of the manuscript. LITERATURE CITED BEYER,F. 1991. North Carolina: the years before man. A geologic history. Carolina Academic Press, Durham, North Carolina. BOUFFORD, D.E. and S.A. SPONGBERG. 1983. Eastern Asian-eastern North American phytogeographical relationships-a history from the time of Linnaeus to the twentieth century. Ann. Missouri Bot. Gard. 70:423-439. BOZEMAN, J.R. 1971. A sociologic and geographic study of the Sand Ridge vegetation in the Coastal Plain of Georgia. Ph.D. Thesis, University of North Carolina, Chapel Hill. BRAUN,E.L. 1936. Notes on Kentucky plants. I. Castanea 1:4145. BRAUN,E.L. 1937. A remarkable colony of coastal plain plants on the Cumberland Plateau in Laurel County, Kentucky. h e r . Midl. Naturalist 18:363-366. BFLAUN, E.L. 1955. The phytogeography of unglaciated eastern United States and its interpretation. Bot. Rev. 21:297-375. BRIDGES,E.L. and S.L. ORZELL.1989. Longleaf pine communities of the West Gulf Coastal Plain. Nat. Areas J . 9:24&263. BUOL,S.W., ed. 1973. Soils of the southern states and Puerto Rico. Southern Cooperative Series Bulletin No. 174. 105 p. CHESTER,E.W., B.E. WOFFORD,R. KRAL, H.R. DESELM,and A.M. EVANS.1993-97. Atlas of Tennessee vascular plants. 2 volumes. Misc. Publ. No. 9 and 13, Center for Field Biology, Austin Peay State University, Clarksville, Tennessee. CHRISTENSEN, N.L. 1988. Vegetation of the southeastern Coastal Plain. p. 317363. In: Barbour, M.G. and W.D. Billings (eds.). North American terrestrial vegetation. Cambridge University Press, United Kingdom. MARCWJUNE 2001
79
CLEWELL, A.F. 1986. Natural setting and vegetation of the Florida Panhandle. COESAMIPDEI-86/001, Contract No. DACW01-77-C-0104.U.S. Army Corps of Engineers, Mobile, Alabama. CORREA, M.A. and R.L. WILBUR.1969. A revision of the genus Carphephorus (Compositae-Eupatorieae). J . Elisha Mitchell Sci. Soc. 85:79-91. CORRELL, D.S. and H.B. CORRELL. 1982. Flora of the Bahama Archipelago. J . Cramer, Germany. CROSSWHITE, F.S. 1980. Dry country plants of the South Texas Plains. Desert Plants 2:141-179. P.A. and H.R. DELCOURT. DELCOURT, 1981. Vegetation maps for eastern North America: 40,000 yr B.P. to the present. p. 123-165. In: R.C. Romans (ed.). Geobotany 11. Plenum Press, New York. DIAMOND, D.D. and F.E. SMEINS.1985. Composition, classification, and species response patterns of remnant tallgrass prairies in Texas. h e r . Midl. Nat. 113:294-308. DRESSLER, R.L. 1954. Some floristic relationships between Mexico and the United States. Rhodora 56:8196. DUNCAN, W.H. 1953. Taxonomic collections of vascular plants in the southeastern states-their abundance and relation to production of floras. Rhodora 55:353-358. ERTTER,B. 2000. Floristic surprises in North America north of Mexico. Ann. Missouri Bot. Gard. 87:81109. FENNEMAN, N.M. 1938. Physiography of Eastern United States. McGraw-Hill, New York. Coastal Plain Province, p. 1-120. FERNALD, M.L. 1918. The geographic affinities of the vascular floras of New England, the Maritime Provinces, and Newfoundland. Amer. J . Bot. 5:219-236. FERNALD,M.L. 1931. Specific segregates and identities in some floras of eastern North America and the Old World. Rhodora 33:53-55. FERNALD, M.L. 1937. Local plants of the inner coastal plain of southeastern Virginia. Rhodora 39:321-366, 379415,433459,465491. FERNALD, M.L. 1950. Gray's manual of botany, 8th ed. American Book Co., Boston. FLEMING,G.P. and N.E. VANALSTINE.1999. Plant communities and floristic features of sinkhole ponds and seepage wetlands in southeastern Augusta County, Virginia. Banisteria 13:67-81. GENTRY,A. 1986. Endemism in the tropical versus temperate plant communities. p. 153-181. In: Soule, M.E. (ed.). Conservation Biology. Sinauer Associates, Sunderland, Massachusetts. GEORGE,R.J. and E.S. NIXON.1990. The herbaceous flora of three Weches Formation outcrops in eastern Texas. Sida 14:117-127. 1964. The natural geography of plants. Columbia University Press, New GLEASON, H.A. and A. CRONQUIST. York. GLEASON,H.A. and A. CRONQUIST. 1991. Manual of vascular plants of northeastern United States and adjacent Canada, 2nd ed. New York Botanical Garden, Bronx. GOULD,F.W. and C.A. CLARK.1978. Dichanthelium (Poaceae) in the United States and Canada. Ann. Missouri Bot. Gard. 65:1088-1132. GRAHAM, A. 1999. Late Cretaceous and Cenozoic history of North American vegetation north of Mexico. Oxford University Press, New York. GRANT,V. 1981. Plant speciation, 2nd ed. Columbia University Press, New York. HARCOMBE, P.A., J.S. GLITZENSTEIN, R.G. KNox, S.L. ORZELL,and E.L. BRIDGES.1993. Vegetation of the longleaf pine region of the West Gulf Coastal Plain. Proc. Tall Timbers Fire Ecology Conf., No. 18: 83-104. HARDIN,E.D. and D.L. WHITE.1989. Rare vascular plant taxa associated with wiregrass (Aristida stricta) in the southeastern United States. Nat. Areas J. 9:234-245. HARPER,R.M. 1906. A phytogeographical sketch of the Altamaha Grit region of the coastal plain of Georgia. Ann. New York Acad. Sci. 17:1415. HARPER,R.M. 1907. Centers of distribution of coastal plain plants. Science, New Series, 25:539-541. HARTMAN, R.L. and B.E. NELSON.1998. Taxonomic novelties from North America north of Mexico: a 20year plant diversity baseline. Missouri Botanical Garden Press, St. Louis. HARVILL, A.M., JR. 1984. On the history of coastal plain species on the Cumberland Plateau and Highland Rim. Sida 10:290-294. HARVILL,A.M., JR.,T.R. BRADLEY, C.E. STEVENS, T.F. WIEBOLDT, D.M.E. WARE,D.W. OGLE,G.W. RAMSEY, and G.P. FLEMING. 1992. Atlas of the Virginia flora, 3rd ed. Virgnia Botanical Associates, Burkeville. HATCH,S.L., K.N. GANDHI,and L.E. BROWN.1990. Checklist of the vascular plants of Texas. Texas Agricultural Experimental Station, Texas A & M University, College Station. W.M. WHITTEN,J.D. SKEAN,JR., R.F. WUNDERLIN, and K.R. DELANEY.1989. A HUCK,R.B., W.S. JUDD, new Dicerandra (Labiatae) from the Lake Wales Ridge of Florida, with a cladistic analysis and discussion of endemism. Syst. Bot. 14:197-213. CASTANEA VOLUME 66
HUNT,C.B. 1974. Natural regions of the United States. W.H. Freeman and Co., San Francisco. JACKSON,S.T. and D.K. SINGER.1997. Climate change and the development of coastal plain disjunctions in the central Great Lakes region. Rhodora 99:lOl-117. JAMES,C.W. 1961. Endemism in Florida. Brittonia 13:225-244. JONES,S.B., JR. and N.C. COILE.1988. The distribution of the vascular flora of Georgia. Department of Botany, University of Georgia, Athens. KARTESZ, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland, 2nd ed. 2 volumes. Timber Press, Portland, Oregon. KARTESZ,J.T. and A. FARSTAD.1999. Multiscale analysis of endemism of vascular plant species. p. 51-54. In: Ricketts, T.H., e t al. 1999. Terrestrial ecoregions of North America. A conservation assessment. Island Press, Washington, D.C. KEDDY,P.A. 1981. Vegetation with Atlantic coastal plain affinities in Axe lake, near Georgian Bay, Ontario. Can. Field-Naturalist 95:241-248. LEBLOND, R.J. 2001. Investigation of environmental conditions associated with plant endemism in the Cape Fear Arch region. Castanea 66:83-97. LEON,H. and H. A W N (J.S. SAUGETand E.E. LIOGIER).1946-63. Flora de Cuba. Five Parts. Contr. Ocas. Del Museo de Hist. Nat. Del Colegio De La Salle, No. 8, 10, 13, 16, Habana. Editorial Universitaria, Universidad de Puerto Rico, Rio Piedras. Reprinted 1974 by Koeltz Science Publishers, Germany. LI, H.-L. 1952. Floristic relationships between eastern Asia and eastern North America. Trans. Amer. Phil. SOC.42:371429. LIOGIER, A.H. 1969. Flora de Cuba. Suplemento. Editorial Sucre, Caracas, Venezuela. MCBRIDE,J .B. 1933. The vegetation and habitat factors of the Carrizo sands. Ecol. Monogr. 3:249-297. MCLAUGHLIN, W.T. 1932. Atlantic Coastal Plain plants in the sand barrens of northwestern Wisconsin. Ecol. Monogr. 2:335-383. MIRANDA, F. and A.J. SHARP.1950. Characteristics of the vegetation in certain temperate regions of eastern Mexico. Ecology 31:313-333. P. 1988. Patterns of plant species distribution on coastal dunes along the Gulf of MexMORENO-CASASOLA, ico. J . Biogeography 15:787-806. NEILL,W.T. 1957. Historical biogeography of present-day Florida. Bull. Florida State Mus. 2:175-220. ORZELL, S.L. and E.L. BRIDGES.1987. Further additions and noteworthy collections in the flora of Arkansas, with historical, ecological, and phytogeographical notes. Phytologia 6423-144. PEATTIE,D.C. 1922. The Atlantic Coastal Plain element in the flora of the Great Lakes. Rhodora 24:5788. PEET, R.K. and D.J. ALLARD.1993. Longleaf pine vegetation of the southern Atlantic and eastern Gulf Coast regions: a preliminary classification. Proc. Tall Timbers Fire Ecology Conf., No. 18:45-81. PYNE, M. 2000. Biogeographic study of the barrens of the southeastern Highland Rim of Tennessee. Prepared for Arnold Air Force Base/Arnold Engineering Development Center, Arnold Air Force Base, Tennessee. RADFORD, A.E., H.E. AHLES,and C.R. BELL.1968. Manual of the vascular flora of the Carolinas. University of North Carolina Press, Chapel Hill. RAVEN,P.H. and D.I. AXELROD.1978. Origin and relationships of the California flora. Univ. California Publ. Bot. 72:l-134. REZNICEK, A.A. 1994. The disjunct coastal plain flora in the Great Lakes region. Biol. Conserv. 68:203215. RICKETTS,T.H., e t al. 1999. Terrestrial ecoregions of North America. A conservation assessment. Island Press, Washington, D.C. ROLAND, A.E. and E.C. SMITH.1969. The flora of Nova Scotia. Proc. Nova Scotia Inst. Sci. Volume 26, Nova Scotia Museum, Halifax. RZEDOWSKI, J. 1993. Diversity and origins of the phanerogamic flora of Mexico. p. 129-144. In: Ramamoorthy, T.P. et al. (eds.). Biological diversity of Mexico: origins and distribution. Oxford University Press, New York. SEMPLE,J.C., V.C. BLOK,and P. HEIMAN.1980. Morphological, anatomical, habit, and habitat differences among the goldenaster genera Chrysopsis, Heterotheca, and Pityopsis (Compositae-Astereae). Can. J . Bot. 58:147-163. SMALL,J.K. 1933. Manual of the southeastern flora. Published by the author, New York. Reprinted 1972 by Hafner Publishing Co., New York. SMITH,E.B. 1988. An atlas and annotated list of the vascular plants of Arkansas, 2nd ed. Published by the author. MARCWJUNE 2001
SNYDER,J.R., A. HERNDON, and W.B. ROBERTSON, JR.1991. South Florida rockland. p. 230-277. In: Myers, R.L. and J.J. Ewe11 (eds.). Ecosystems of Florida. University of Central Florida Press, Orlando. SORRIE,B.A. and R.J. LEBLOND.1997. Vascular plants new to the Bahamas and Andros Island. Bahamas J . Sci. 4:14-18. SORRIE,B.A., B. VAN EERDEN,and M.J. Russo. 1997. Noteworthy plants from Fort Bragg and Camp MacKall, North Carolina. Castanea 62:239-259. SORRIE,B.A. and A.S. WEAKLEY. In prep. Endemic vascular plant taxa of the Atlantic and Gulf Coastal Plains of North America. STEBBINS, G.L. 1947. Evidence on rates of evolution from the distribution of existing and fossil plant species. Ecol. Monogr. 17:151-158. STEIN,B.A., L.S. KUTNER,and J.S. ADAMS.2000. Precious heritage. The status of biodiversity in the United States. Oxford University Press, New York. SVENSON, H.K. 1941. Notes on the Tennessee flora. J. Tennessee Acad. Sci. 16:lll-160. TAKHTAJAN, A. 1986. Floristic regions of the World. University of California Press, Berkeley. TAYLOR, R.J. and C.E.S. TAYLOR.1994. An annotated list of the ferns, fern allies, and flowering plants of Oklahoma, 3rd ed. Biology Department Herbarium, Southeastern Oklahoma State University, Durant. THOMAS,R.D. and C.M. ALLEN.1993-98. Atlas of the vascular flora of Louisiana. 3 Volumes. Louisiana Department of Wildlife and Fisheries and The Nature Conservancy, Louisiana Field Office, Baton Rouge. THORNE,R.F. 1993. Phytogeography. p. 132-153. In: Flora of North America Editorial Committee (eds.). 1993+. Flora of North America north of Mexico. Volume 1. Introduction. Oxford University Press, New York. TOWNSEND, J.F. (ed.). 1999. South Carolina plant atlas. http:/cricket.biol.sc.edu/herb/. WALKER, H.J. and J.M. COLEMAN. 1987. Atlantic and Gulf Coastal Province. p. 51-110. In: Graf, W.L. (ed.). Geomorphic systems of North America. Geological Society of America, Centennial Special Volume 2, Boulder, Colorado. WALKER,J . 1993. Rare vascular plant taxa associated with the longleaf pine ecosystems: patterns in taxonomy and ecology. Proc. Tall Timbers Fire Ecology Conf., No. 18:105-125. WARE,S., C. FROST,and P.D. DOERR.1993. Southern mixed hardwood forest: the former longleaf pine forest. p. 447-493. In: Martin, Boyce, and Echternacht (eds.). Biodiversity of the southeastern United States. Lowland Terrestrial Communities. J. Wiley and Sons, New York. WEAKLEY, A.S. 2000. Flora of the Carolinas and Virginia, working draft of May 2000. The Nature Conservancy, Durham, North Carolina. WOOD,C. E., JR.1971. Some floristic relationships between the southern Appalachians and western North America. p. 331-402. In: Holt, P.C. (ed.). The distributional history of the biota of the southern Appalachians. Part 11. Flora. Virginia Polytechnic Institute, Blacksburg. WU, Z. 1983. On the significance of Pacific intercontinental discontinuity. Ann. Missouri Bot. Gard. 70: 577-590. WUNDERLIN, R.P. 1998. Guide to the vascular plants of Florida. University Presses of Florida, Tampa. WUNDERLIN, R.P., B.F. HANSEN,and E.L. BRIDGES.1996. Atlas of Florida vascular plants (CD-ROM). Institute for Systematic Botany, University of South Florida, Tampa.
CASTANEA VOLUME 66
http://www.jstor.org
LINKED CITATIONS - Page 1 of 3 -
You have printed the following article: Coastal Plain Vascular Plant Endemics: Phytogeographic Patterns Bruce A. Sorrie; Alan S. Weakley Castanea, Vol. 66, No. 1/2, Southeastern Endemics: Speciation and Biogeography: University of North Carolina at Wilmington. April 15, 1999. (Mar. - Jun., 2001), pp. 50-82. Stable URL: http://links.jstor.org/sici?sici=0008-7475%28200103%2F06%2966%3A1%2F2%3C50%3ACPVPEP%3E2.0.CO%3B2-B
This article references the following linked citations. If you are trying to access articles from an off-campus location, you may be required to first logon via your library web site to access JSTOR. Please visit your library's website or contact a librarian to learn about options for remote access to JSTOR.
Literature Cited Eastern Asian-Eastern North American Phytogeographical Relationships-A History From the Time of Linnaeus to the Twentieth Century D. E. Boufford; S. A. Spongberg Annals of the Missouri Botanical Garden, Vol. 70, No. 3. (1983), pp. 423-439. Stable URL: http://links.jstor.org/sici?sici=0026-6493%281983%2970%3A3%3C423%3AEANAPR%3E2.0.CO%3B2-5
Composition, Classification and Species Response Patterns of Remnant Tallgrass Prairies in Texas David D. Diamond; Fred E. Smeins American Midland Naturalist, Vol. 113, No. 2. (Apr., 1985), pp. 294-308. Stable URL: http://links.jstor.org/sici?sici=0003-0031%28198504%29113%3A2%3C294%3ACCASRP%3E2.0.CO%3B2-O
Floristic Surprises in North America North of Mexico Barbara Ertter Annals of the Missouri Botanical Garden, Vol. 87, No. 1. (Winter, 2000), pp. 81-109. Stable URL: http://links.jstor.org/sici?sici=0026-6493%28200024%2987%3A1%3C81%3AFSINAN%3E2.0.CO%3B2-B
http://www.jstor.org
LINKED CITATIONS - Page 2 of 3 -
The Geographic Affinities of the Vascular Floras of New England, The Maritime Provinces and Newfoundland M. L. Fernald American Journal of Botany, Vol. 5, No. 5. (May, 1918), pp. 219-236. Stable URL: http://links.jstor.org/sici?sici=0002-9122%28191805%295%3A5%3C219%3ATGAOTV%3E2.0.CO%3B2-9
Dichanthelium (Poaceae) in the United States and Canada Frank W. Gould; Carolyn A. Clark Annals of the Missouri Botanical Garden, Vol. 65, No. 4. (1978), pp. 1088-1132. Stable URL: http://links.jstor.org/sici?sici=0026-6493%281978%2965%3A4%3C1088%3AD%28ITUS%3E2.0.CO%3B2-B
A New Dicerandra (Labiatae) from the Lake Wales Ridge of Florida, with a Cladistic Analysis and Discussion of Endemism Robin B. Huck; Walter S. Judd; W. Mark Whitten; James D. Skean, Jr.; Richard P. Wunderlin; Kris R. Delaney Systematic Botany, Vol. 14, No. 2. (Apr. - Jun., 1989), pp. 197-213. Stable URL: http://links.jstor.org/sici?sici=0363-6445%28198904%2F06%2914%3A2%3C197%3AAND%28FT%3E2.0.CO%3B2-2
Endemism in Florida C. W. James Brittonia, Vol. 13, No. 3. (Jul. 15, 1961), pp. 225-244. Stable URL: http://links.jstor.org/sici?sici=0007-196X%2819610715%2913%3A3%3C225%3AEIF%3E2.0.CO%3B2-P
Atlantic Coastal Plain Plants in the Sand Barrens of Northwestern Wisconsin W. T. McLaughlin Ecological Monographs, Vol. 2, No. 3. (Jul., 1932), pp. 335-383. Stable URL: http://links.jstor.org/sici?sici=0012-9615%28193207%292%3A3%3C335%3AACPPIT%3E2.0.CO%3B2-D
Characteristics of the Vegetation in Certain Temperate Regions of Eastern Mexico F. Miranda; A. J. Sharp Ecology, Vol. 31, No. 3. (Jul., 1950), pp. 313-333. Stable URL: http://links.jstor.org/sici?sici=0012-9658%28195007%2931%3A3%3C313%3ACOTVIC%3E2.0.CO%3B2-0
http://www.jstor.org
LINKED CITATIONS - Page 3 of 3 -
Evidence on Rates of Evolution from the Distribution of Existing and Fossil Plant Species G. Ledyard Stebbins, Jr. Ecological Monographs, Vol. 17, No. 2. (Apr., 1947), pp. 149-158. Stable URL: http://links.jstor.org/sici?sici=0012-9615%28194704%2917%3A2%3C149%3AEOROEF%3E2.0.CO%3B2-8
On the Significance of Pacific Intercontinental Discontinuity Wu Zhengyi Annals of the Missouri Botanical Garden, Vol. 70, No. 4. (1983), pp. 577-590. Stable URL: http://links.jstor.org/sici?sici=0026-6493%281983%2970%3A4%3C577%3AOTSOPI%3E2.0.CO%3B2-8
