Appalachian Forests
At higher elevations, above 1300m spruce-fir forests predominate including Picea rubens red spruce, and the endemic Abies balsam balsam fir and Abies fraseri fraser fir (Pinaceae). At lower elevations between 250-1300 m mixed oak (Quercus spp.) forests predominate which once supported massive tulip trees Lirodendron tulipifera and endemic chestnut Castanea dentate (Fagaceae). However, in the 1900s the spread of chestnut blight caused by the fungus Cryphonectria parasitica resulted in the widespread loss of chestnut. This allowed species such as Quercus prinus, Q. rubra, Q. velutina and the endemic locust tree Robinia pseudoacacia (Fabaceae) to profliferate. Other endemic trees of semi-upland areas include the two endemic lime trees Tilia americana and T. heterophylla (Tiliaceae). In the rolling hills west of the Appalachian Mountains are relicts of ancient mesic forests that once covered much of the temperate regions of North America. These support a variety of forest types with magnolias such as the endemic Magnolia acuminata and M. fraseri (Magnoliaceae), endemic oaks (Quercus), endemic hickories (Carya), walnuts including the endemic Juglans cinerea (Juglandaceae), elms including the endemic Ulmus serotina and U. thomasii (Ulmaceae), locusts including the endemic Robinia hispida (Fabaceae), maples including the endemic Acer nigrum, A. pensylvanicum, and A. saccharum (Aceraceae) together with the endemic conifer Tsuga canadensis (Pinaceae) Eastern Hemlock. Understory species include various endemic rhododendron, the endemic Prunus alleghaniensis (Rosaceae) and the rich ground layer comprising various endemic vernal species such as Allium tricoccum (Alliaceae), Caulophyllum thalictroides (Berberidaceae), Claytonia virginica (Portulacaceae), Dicentra canadensis, D. cucullaria (Fumariaceae), and Laportea Canadensis (Urticaceae), while the more shade tolerant endemics include Asarum canadense (Aristolochiaceae) and Fragaria virginiana (Rosaceae).
Appalachian Ozark Mountain Forests
These forests situated mainly on the Quachita and Boston Mountain comprises some of the best-developed oak-hickory forest in the United States. The primary species are Quercus rubra, Q. alba, various Carys species especially Carya texcana. Associated endemic taxa include Tilia Americana (Tiliaceae).
Appalachian Southern Great Lakes Forest
On the basis of species composition, these forests can be divided into the western zone which includes north Michigan, north Wisconsin and north Minnesota, the southern zone which includes southern Michigan much of Ohio and Indiana, and part of Ontario, and the eastern zone which includes the lowland areas of New York parts of Vermont, Quebec and southern Ontario. However, there are a number of trees common to all three areas - endemics among these include Abies balsamea (Pinaceae), Acer saccharum (Aceraceae) Tilia americana (Tiliaceae) and Tsuga canadensis (Pinaceae).
Appalachian Shale Barrens
In the mid-Appalachian region there are a series of Palaeozoic shale outcrops known as the Shale Barrens. In contrast to the surrounding woodlands, these support relatively sparse vegetation. This is mainly due to their low nutrient status, lack of moisture, high temperatures and insolation levels. In fact, the habitat has been described as an eastern counterpart of North America’s western deserts. These peculiar conditions have led to the development of about 18 endemic taxa including two palaeoendemics Phlox buckleyi (Polemoniaceae) and Trifolium virginicum (Fabaceae), seven neoendemics Allium oxyphilum (Alliaceae), Arabis serotina (Brassicaceae), Astragalus distortus, var. distortus (Fabaceae), Aster schistosus (Asteraceae), Clematis coactilis, C. viticaulis (Ranunculaceae) and Solidago arguta var. harrisii (Asteraceae), six holoendemics (Calystegia spithamaea subsp. purschiana (Convolvulaceae), Clematis ablicoma (Ranunculaceae), Eriogonum allenii (Polygonaceae), Paronychia Montana (Caryophyllaceae), Pseudotaenidia montana (Apiaceae) and Senecio antennariifolius (Asteraceae), two patroendemics (Antennaria virginica (Asteraceae) and Oenothera argillicola (Onagraceae) and one apoendemic Helianthus laevigatus (Asteraceae). All of these are obligate heliophytes and it seems that the high levels of exposure to sunlight has been one of the main driving forces behind the creation of these endemics.
Appalachian Cumberland Plateau Formations
To the west of the folded Appalachians are a series of uplifted plateaus composed of Palaeozoic sediments that has developed into another endemic hotspot. Some of the endemic species include Arenaria cumberlandensis (Caryophyllaceae), Coreopsis pulchra (Asteraceae), Eupatorium luciae-brauniae (Asteraceae), Silene rotundifolia (Caryophyllaceae) Silphium brachiatum, S. mohrii (Asteraceae) and Solidago albopilosa (Asteraceae).
Appalachian Piedmont Granite Flatrocks Formations
Apart from Stone Mountain - a gigantic boulder some 235 m high - most of the boulders are relatively flat as their name implies. Most are also very exposed with only thin patches of soil, but seasonal pools may develop. The main species including Arenaria brevifolia, Lotus helleri and Talinum teretifolium are all typical of dry habitats. Like the Shale Barrens this unusual habitat has its own assemblage of endemic plant including two monotypic genera (Diamorpha and Amphianthus) and about twelve endemic or near endemic species such as Aster avitus (Asteraceae), Isoetes melanospra, Isoetes tegetiformans (Isoetaceae), Hypericum splendens (Hypericaceae) Juncus georgianus (Juncaceae), Portulaca smallii (Portulacaceae) Quercus georgianai (Fagaceae), Rhynchospora saxicola (Cyperaceae), Sedum pusillum (Crassulaceae) and Viguiera porteri (Asteraceae).
Further information required.
References
Cain, S. A. 1943. The Tertiary character of the Cove hardwood forests of the Great Smoky Mountains National Park. Bulletin of the Torrey Botanical Club, 70: 213-235.
Cooper, A. W. 1979. The natural vegetation of North Carolina. In: Contributions to the knowledge of flora and vegetation in the Carolinas. Eds. H. Leith and E. Landolt. VGI Zurich.
Estill, J. C. & Cruzan, M. B. 2001. Phytogeography of rare plant species endemic to the southeastern United States. Castanea, 66: 3-23.
Greller, A. M. 1989. Deciduous Forest. In: North American Terrestrial Vegetation. Eds. M. G. Barbour & W. D. Billings. Cambridge University Press.
McKell, C. M. & Garcia-Moya, E. 1989. North American Shrublands. In: The Biology and Utilization of Shrubs. Ed. C. M. McKell. Academic Press, Inc.
Keener, C. S. 1983. Distribution and biohistory of the endemic flora of the Mid-Appalachian Shale Barrens. The Botanical Review, 49: 65-115.
Pittillo, J. D. & Smathers, G. A. 1979. Phytogeography of the Balsam Mountains and Pisgah Ridge, Southern Appalachian Mountains. In: Contributions to the knowledge of flora and vegetation in the Carolinas. Eds. H. Leith and E. Landolt. VGI Zurich.
Qian, H. 1999. Floristic analysis of vascular plant genera of North America north of Mexico: characterization and phytogeography. Journal of Biogeography, 26: 1307-1321.
Ricketts, T. h. et al. 1999. Terrestrial Ecosystems of North America - a conservation assessment. World Wildlife Fund, USA and Canada. Island Press, Washington.