The
Interior Low Plateau is a region in the
Upper South that is known for its calcareous glade communities. This region is centered in
Tennessee and
Kentucky, and extends into northern
Alabama, and southern
Illinois, southern
Indiana, and southern
Ohio. These glades are best developed in the area of the
Central Basin (or Nashville Basin) in Tennessee, where they are geographically widespread and harbor high levels of endemism. Outside of the Central Basin, calcareous glades are found in lower numbers throughout the Interior Low Plateau, and species
endemism is greatly reduced. Glades in the Interior Low Plateaus are characterized by species such as one-flower gladecress (
Leavenworthia uniflora), limestone skullcap (
Scutellaria parvula), widow's-cross stonecrop (
Sedum pulchellum), poverty dropseed (
Sporobolus vaginiflorus) and glade violet (
Viola egglestonii).
Central Basin cedar glades The limestone glades of the Central Basin in Tennessee are often called "cedar glades". The name comes from the abundance of eastern red cedar (
Juniperus virginiana) that occurs on the margins of the glades or in cracks in the bedrock where the roots can gain a foothold. Many of the characteristic plants that grow in the limestone glades of the Central Basin are endemics that occur nowhere else, or disjunct populations of plants that are widespread in the
prairies of the central U.S. Some species with highly restricted ranges that occur in the glades of the Central Basin include the Tennessee coneflower (
Echinacea tennesseensis), Pyne's ground plum (
Astragalus bibullatus), leafy prairie clover (
Dalea foliosa), Tennessee milkvetch (
Astragalus tennesseensis), Nashville breadroot (
Pediomelum subacaule), and limestone fameflower (
Phemeranthus calcaricus). ,
Wilson County, Tennessee These glades can be saturated with water in the winter and spring, leading to "xerohydric" (dry/wet alternating) conditions.
Threats to the cedar glades The central basin (or Nashville Basin) of Tennessee is one of the largest areas containing limestone glades. Because of the rapid growth of metropolitan
Nashville and the surrounding cities of
Murfreesboro and
Lebanon, many of the limestone glades have been destroyed by development. The State of Tennessee and the Nature Conservancy have established a number of parks and preserves to protect important plant populations.
Cedars of Lebanon State Park in
Wilson County and
Long Hunter State Park in
Davidson County both protect substantial limestone glade ecosystems.
Limestone slope glades The limestone slope glades of
Kentucky are a globally vulnerable habitat consisting of limestone glades found on hillsides, which are wet in the spring but become very dry in the rest of the year. This provides habitat for unique species such as necklace glade cress, Butler's quillwort, and Crawe's sedge.
Endemic plant species This is a list of calcareous glade-adapted plant species considered endemic to the Interior Low Plateau region. Some are found in only a single county of a single state. •
Astragalus bibullatus •
Astragalus tennesseensis •
Castilleja kraliana (Cahaba paintbrush) •
Clinopodium glabellum •
Dalea cahaba •
Dalea foliosa •
Dalea gattingeri •
Delphinium alabamicum •
Echinacea tennesseensis •
Eleocharis bifida (Cedar glade spike rush) •
Erigeron dolomiticola (Cahaba daisy fleabane) •
Hypericum dolabriforme (Glade St. John's wort) •
Leavenworthia uniflora •
Lithospermum decipiens (Deceptive marbleseed) •
Lobelia gattingeri (Gattinger's lobelia) •
Marshallia mohrii (Coosa Barbara's-buttons) •
Pediomelum subacaule •
Penstemon tenuiflorus (Limestone beardtongue) •
Phemeranthus calcaricus (Limestone fameflower) •
Physaria filiformis •
Rudbeckia grandiflora (Largeflower coneflower) •
Silphium glutinosum (Sticky rosinweed) •
Sisyrinchium calciphilum (Glade blue-eyed grass) •
Spigelia alabamensis (Alabama pinkroot) •
Symphyotrichum kentuckiense (Miss Price's aster) ==Ozark Mountains glades==