Natural Bridge State Resort Park is a Kentucky state park located in Powell and Wolfe Counties along the Middle Fork of the Red River, adjacent to the Red River Gorge Geologic Area and surrounded by the Daniel Boone National Forest. Its namesake natural bridge is the centerpiece of the park. The natural sandstone arch spans 78 ft (24 m) and is 65 ft (20 m) high. The natural process of weathering formed the arch over millions of years. The park is approximately 2,300 acres (9 km2) of which approximately 1,200 acres (5 km2) is dedicated by the Office of Kentucky Nature Preserves as a nature preserve. In 1981 this land was dedicated into the nature preserves system to protect the ecological communities and rare species habitat. The first federally endangered Virginia big eared bats, Corynorhinus townsendii virginianus, recorded in Kentucky were found at Natural Bridge State Resort Park in the 1950s.
Eurybia radula, commonly known as the low rough aster or rough wood aster, is an herbaceous perennial in the family Asteraceae. It is native to eastern North America where it is present from Newfoundland and Labrador in the far northeast of Canada, west to Ontario and south to Kentucky and Virginia in the United States. The low rough aster is also present on the French overseas territory of St. Pierre and Miquelon just south of Newfoundland. It typically grows in wet soils in a wide variety of habitats from bogs and fens to creek shores to ditches. Although it is not considered threatened over most of its distribution, it is imperiled or possibly extirpated over much of its range in the United States. Its flower heads emerge in the late summer to early fall and show pale blue-violet rays with yellow centres.
Asplenium rhizophyllum, the (American) walking fern, is a frequently-occurring fern native to North America. It is a close relative of Asplenium ruprechtii which is found in East Asia and also goes by the common name of "walking fern".
Asplenium montanum, commonly known as the mountain spleenwort, is a small fern endemic to the eastern United States. It is found primarily in the Appalachian Mountains from Vermont to Alabama, with a few isolated populations in the Ozarks and in the Ohio Valley. It grows in small crevices in sandstone cliffs with highly acid soil, where it is usually the only vascular plant occupying that ecological niche. It can be recognized by its tufts of dark blue-green, highly divided leaves. The species was first described in 1810 by the botanist Carl Ludwig Willdenow. No subspecies have been described, although a discolored and highly dissected form was reported from the Shawangunk Mountains in 1974. Asplenium montanum is a diploid member of the "Appalachian Asplenium complex," a group of spleenwort species and hybrids which have formed by reticulate evolution. Members of the complex descended from A. montanum are among the few other vascular plants that can tolerate its typical habitat.
Asplenium pinnatifidum, commonly known as the lobed spleenwort or pinnatifid spleenwort, is a small fern found principally in the Appalachian Mountains and the Shawnee Hills, growing in rock crevices in moderately acid to subacid strata. Originally identified as a variety of walking fern, it was classified as a separate species by Thomas Nuttall in 1818. It is believed to have originated by chromosome doubling in a hybrid between walking fern and mountain spleenwort, producing a fertile tetraploid, a phenomenon known as alloploidy; however, the hypothesized parental hybrid has never been located. It is intermediate in morphology between the parent species: while its leaf blades are long and tapering like that of walking fern, the influence of mountain spleenwort means that the blades are lobed, rather than whole. A. pinnatifidum can itself form sterile hybrids with several other spleenworts.
Asplenium bradleyi, commonly known as Bradley's spleenwort or cliff spleenwort, is a rare epipetric fern of east-central North America. Named after Professor Frank Howe Bradley, who first collected it in Tennessee, it may be found infrequently throughout much of the Appalachian Mountains, the Ozarks, and the Ouachita Mountains, growing in small crevices on exposed sandstone cliffs. The species originated as a hybrid between mountain spleenwort and ebony spleenwort ; A. bradleyi originated when that sterile diploid hybrid underwent chromosome doubling to become a fertile tetraploid, a phenomenon known as allopolyploidy. Studies indicate that the present population of Bradley's spleenwort arose from several independent doublings of sterile diploid hybrids. A. bradleyi can also form sterile hybrids with several other spleenworts.
Geocarpon is a monotypic genus of flowering plants in the family Caryophyllaceae. It contains the single species Geocarpon minimum, which is known by the common names tinytim and earth-fruit. It is a rare plant known from about 34 populations in the US states of Arkansas, Louisiana, Missouri, and Texas. There are a number of threats to its survival and it was listed as a threatened species of the United States in 1987.
Thaspium is a genus of flowering plants in the Apiaceae. A common name for the various Thaspium species is meadowparsnip or meadow-parsip. Its native range is eastern North America, from eastern Texas in the southwest to Maine in the northeast.
Synandra is a monotypic genus of flowering plants in the mint family containing the single species Synandra hispidula, which is known by the common name Guyandotte beauty. It is native to the east-central United States where it ranges from southern Illinois to western North Carolina and Virginia.
Asplenium × gravesii, commonly known as Graves' spleenwort, is a rare, sterile, hybrid fern, named for Edward Willis Graves (1882–1936). It is formed by the crossing of Bradley's spleenwort (A. bradleyi) with lobed spleenwort (A. pinnatifidum). It is only found where its parent species are both present; in practice, this proves to be a few scattered sites in the Appalachian Mountains, Shawnee Hills, and Ozarks, reaching perhaps its greatest local abundance around Natural Bridge State Resort Park. Like its parents, it prefers to grow in acid soil in the crevices of sandstone cliffs.
Asplenium × trudellii, commonly known as Trudell's spleenwort, is a rare hybrid fern of the eastern United States, first described in 1925. It is formed by the crossing of mountain spleenwort (A. montanum) with lobed spleenwort (A. pinnatifidum). Trudell's spleenwort is intermediate in form between its two parents, and is generally found near them, growing on exposed outcrops of acidic rock. While A. × trudellii is triploid and sterile, there is some evidence that it can occasionally reproduce apogamously.
Asplenium × kentuckiense, commonly known as Kentucky spleenwort, is a rare, sterile, hybrid fern. It is formed by the crossing of lobed spleenwort (A. pinnatifidum) with ebony spleenwort (A. platyneuron). Found intermittently where the parent species grow together in the eastern United States, it typically grows on sandstone cliffs, but is known from other substrates as well.
Silphium pinnatifidum, the tansy rosinweed or cutleaf prairie dock, is a species of flowering plant in the family Asteraceae. It is native to the Southeastern United States where it is found in Alabama, Georgia, Kentucky, and Tennessee. Its habitat is prairies, barrens, and cedar glades.
Clinopodium glabellum, the glade calamint, is a species of flowering plant in the mint family. It is native to the Nashville Basin of Tennessee, the Bluegrass Region of Kentucky, and two counties in Alabama. Within this range, it is found only on wet cedar glades and in seeps along limestone creekbeds. Due to its narrow range and specific habitat requirements, this species is considered vulnerable.
Silphium mohrii, known by the common names Mohr's rosinweed and shaggy rosinweed, is a species of flowering plant in the family Asteraceae. It is native to the Southeastern United States, where it is native only to northern Alabama, southern Tennessee, and extreme northwest Georgia. It is native to prairie remnants and rocky limestone openings. Because of its restricted range and severely declined habitat, it is considered a vulnerable species.
Euthamia caroliniana, known as Carolina grass-leaved goldenrod or slender goldentop is a flowering plant in the genus Euthamia, a member of the family Asteraceae. It is listed as Vulnerable due to habitat loss and disturbance within its range.
Gratiola quartermaniae, commonly known as the limestone hedge-hyssop, is a species of flowering plant in the plantain family. It is native to eastern North America.
Elymus svensonii, commonly called Svenson's wildrye, is a species of flowering plant in the grass family (Poaceae). It is native to United States, where it is endemic to the Interior Low Plateau of Kentucky and Tennessee. Its natural habitat is on dry, rocky, limestone river bluffs.
Osmia calaminthae, commonly known as the blue calamintha bee, is a rare species of mason bee known only from two small areas in Florida, United States. It is considered Critically Imperiled by NatureServe. The common name for the bee is derived from its distinctly blue color and its favored host plant, Calamintha ashei.
Thaspium trifoliatum, commonly called meadow-parsnip or purple meadow-parsnip is a species of flowering plant in the carrot family (Apiaceae). It is native to eastern North America where it is found in many eastern U.S states and in Ontario, Canada. It has a broad natural habitat, which includes mesic to dry forests and woodlands, prairies, bluffs, and rock outcrops.
