Tradescantia ozarkana

E.S. Anderson & Woods.

Ozark Spiderwort

G3Vulnerable Found in 2 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.136941
Element CodePMCOM0B0H0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassMonocotyledoneae
OrderCommelinales
FamilyCommelinaceae
GenusTradescantia
Other Common Names
Ozark spiderwort (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank MethodLegacy Rank calculation - Biotics v1
Review Date2020-03-12
Change Date1996-08-08
Edition Date2020-03-12
Edition AuthorsT. Smith/K. Maybury (1996); Watson, William C. (1994)., rev. L. Oliver (2020)
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
Tradescantia ozarkana is endemic to the Ozark Mountains of Missouri, Oklahoma, and Arkansas and the Ouachita Mountains of western Arkansas and southeastern Oklahoma. There are fifteen extant populations in Missouri, more than that in Arkansas, and a few in Oklahoma. It is threatened by feral hogs. The species is considered relatively secure despite some documented declines due to construction of dams/impoundments.
Range Extent Comments
Tradescantia ozarkana is presently restricted to the Ozark and Ouachita Mountains of the Interior Highlands of southwestern Missouri, northwestern Arkansas, and extreme eastern Oklahoma.
Occurrences Comments
Seventy-four element occurrences are known from across the range of T. ozarkana: thirty in Arkansas, twenty-eight in Missouri (fifteen post-1980 occurrences), and sixteen in Oklahoma (ten post-1980 occurrences) (these numbers might be out of date).
Threat Impact Comments
This species is threatened by feral hogs which can cause extensive damage to habitats they've invaded by trampling, rooting, and creating wallows. Specifically, feral hogs threaten this species in the Devil's Eyebrow Natural Area in Arkansas, however, hog management is underway (Lynch et al. 2019). Other potential local threats that are of particular danger to T. ozarkana stem from destruction of habitat through forest clearing and livestock pasturing. Succession of habitat may also threaten populations by shading out individuals through increased cover from tree canopies (Smith 1992).
Ecology & Habitat

Diagnostic Characteristics

Anderson and Woodson (1935) reported that Tradescantia ozarkana "is obviously most closely related to T. edwardsiana of south-central Texas" and that "the two species evidently differ almost entirely in their foliage." However, since the ranges of these two taxa do not overlap, a problem of identification should not exist.

Steyermark (1963) described a second woodland species of Tradescantia from the Ozark region, T. longipes, whose range overlaps that of T. ozarkana. These two taxa are differentiated by the larger leaf blades (15-50 mm.) in T. ozarkana which are more or less glaucous and hairless except at the margins.

A combination of the following characteristics from Anderson and Woodson (1935) should be diagnostic in distinguishing T. ozarkana from all other species of spiderworts in North America: erect or ascending stems, very conspicuous bracts, at least the upper leaf blades broader than the sheath, sepals 0.4-1.0 cm long, leaf blades directly constricted into the sheath and capsules 0.6-0.8 cm long. Watson (1992) reported pale-green leaves with crinkled edges as a special identifying feature for Tradescantia ozarkana.

Habitat

Tradescantia ozarkana occurs in steep, rocky, wooded slopes and ravines, bases and mesic lower slopes of bluffs as well as dry to moist woodland ledges (Steyermark 1963, AR NHC 1992 and MO NHD 1994). It is most often associated with a limestone/dolomite substrate, T. ozarkana has also been reported from sandstone by Watson (1989). The taxon is recorded between 500 and 2,550+ feet in elevation. Slope aspect does not appear to be a limiting habitat factor.

Tradescantia ozarkana does not appear to be highly habitat specific (Foti 1994). Throughout its range, it has been recorded from rich, diverse, mainly deciduous woodlands. Herbaceous associates are not well-known. At a Newton County, Arkansas site, they include Adiatum pedatum, Arisaema atrorubens, Cystopteris fragilis, Impatiens capensis, Trillium viridescens, and Uvularia grandiflora (AR NHC 1992). Asclepias quadrifolia, Carex latebracteata, Dodecatheon meadia, Hedyotis ouachitana, Silene virginica, and Tradescantia ohiensis are associates at a McCurtain County, Oklahoma site (Watson 1989).

Ecology

Very little ecological information is available for this taxon. Flowering occurs in April and May and populations generally range in size from 10-20 individuals to several thousand (Watson 1989, AR NHC 1992, MO NHD 1994). This suggests that under optimum conditions, the species may be able to build up large population numbers at a given site.

Steyermark (1963) reported that T. ozarkana hybridizes with T. ernestiana in Barry County at Eagle Rock near Roaring River State Park and with T. ohiensis in Ozark and Taney Counties in Missouri. "The latter hybrid is a broad-leaved, glaucous plant with often glabrous or only hairy-tipped sepals."
Terrestrial Habitats
Forest/Woodland
Other Nations (1)
United StatesN3
ProvinceRankNative
MissouriS2Yes
ArkansasS3Yes
OklahomaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
7 - Natural system modificationsLarge - smallUnknownHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)UnknownHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)UnknownHigh (continuing)
11 - Climate change & severe weatherLarge - smallUnknownHigh (continuing)
11.1 - Habitat shifting & alterationLarge - smallUnknownHigh (continuing)

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (2)
Arkansas (2)
AreaForestAcres
Dismal CreekOzark-St. Francis National Forest9,160
Richland CreekOzark-St. Francis National Forest571
References (11)
  1. Anderson, E. and R.E. Woodson. 1935. The species of <i>Tradescantia </i>indigenous to the United States. J. Arnold Arbor. 9: 1-132.
  2. Foti, Tom. 1994. Chief of Research/Ecologist, Arkansas Natural Heritage Commission.
  3. Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. 3 volumes. Hafner Press, New York. 1732 pp.
  4. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  5. Lynch, D., C. T. Witsell, B. A. Rupar, W. C. Holimon, and D. W. Bowman. 2019. The devil and the deep blue lake: how natural area acquisition and stewardship helps protect the major drinking resevoir in northwestern Arkansas. Natural Areas Journal 39(1): 78-89.
  6. Olsen, A. 2014. Habitat assessments of two narrowly endemic plant species, Ozark spiderwort (<i>Tradescantia ozarkana) </i>E. S. Anderson and Woods and Newton's larkspur <i>(Delphinium newtonianum) </i>D. M. Moore. Unpublished Master's Thesis. University of Arkansas. Accessed online on 3/10/2020 at: <a href="https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=3854&amp;context=etd">https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=3854&amp;context=etd</a>
  7. Smith, Tim. Personal communication. Botanist, Missouri Department of Conservation. Missouri Department of Conservation, Jefferson City, MO
  8. Steyermark, J.A. 1963. Flora of Missouri. Iowa State Univ. Press, Ames. 1728 pp.
  9. Watson, L.E. 1989. Status survey of Tradescantia ozarkana, Ozark spiderwort, in Oklahoma. Oklahoma Natural Heritage Inventory, Norman. 8 pp.
  10. Watson, L.E. 1992. Plant candidate inventory of McCurtain County Wilderness Area. Unpublished report submitted to the U.S. Fish and Wildlife Service. Tulsa, Oklahoma.
  11. Watson, L.E. 1993. Monitoring of plant candidate species in Oklahoma, year two. Unpublished report submitted to the U.S. Fish and Wildlife Service. Tulsa, Oklahoma.