Roadless Areas
Home/Species/ Canby's Mountain-lover

Paxistima canbyi

Gray

Canby's Mountain-lover

G2Imperiled (G2?) Found in 3 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
High - lowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.140694
Element CodePDCEL0A010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single nation
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCelastrales
FamilyCelastraceae
GenusPaxistima
Synonyms
Pachistima canbyiGray
Other Common Names
Canby's mountain-lover (EN) pachistima de Canby (FR)
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.
Taxonomic Comments
Name of genus spelled 'Pachistima' in most older works. However, actual spelling by Rafinesque in original publication was 'Paxistima', which current code of nomenclature is widely interpreted as requiring acceptance, despite Rafinesque's frequent typographical substitution of 'x' for "ch" in many of his works (e.g., Xamaesyce for Chamaesyce) and his prior and subsequent spellings of this name as 'Pachistima'. For discussion see Navaro & Blackwell (1990) in Sida 14(2): 231. Larry Morse 8Feb98.
Conservation Status
Rank MethodLegacy Rank calculation - Excel v3.1x
Review Date2017-06-07
Change Date2017-06-07
Edition Date2017-06-07
Edition AuthorsMorse, L.; rev. C. Ludwig/K. Maybury; rev. D. Walton (7/96), rev. L. Morse (1999, 2001), rev. Maybury 2004, rev. K. Gravuer (2009), rev. L. Oliver (2017)
Threat ImpactHigh - low
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
A regional endemic known from the central Appalachians of western Virginia, eastern West Virginia, western Maryland, and southern Pennsylvania, as well as from the Interior Low Plateau of central Kentucky, southern Ohio, and central Tennessee; a few occurrences are also known from the intervening Cumberlands/Southern Ridge and Valley region. Approximately 67 occurrences are believed extant, mostly in West Virginia, Virginia, and Kentucky. The number of genetic individuals may be very low, as a single genotype can comprise much or all of the occupied area at some sites. Euonymus scale (Unaspis euonymi) is a major threat in Kentucky, with more than 80% of occurrences found to be drastically declining in a recent statewide survey. The magnitude of this threat elsewhere in the range is as-yet undetermined; the scale is also known to occur in at least Virginia as well, although it has not yet been observed in other parts of the range such as Ohio. P. canbyi may also be declining (possibly severely) in West Virginia, presumably due to deer browsing. The species is protected from many other threats by the nature of its habitat; other minor impacts include quarrying, fires, indirect erosional impacts from nearby clearcutting, trampling, collecting, and grazing.
Range Extent Comments
Occurrences appear to be in two major groups, one in the central Appalachians of southern Pennsylvania, western Maryland, western Virginia, and eastern West Virginia, and the other in the Interior Low Plateau of central Kentucky, southern Ohio, and central Tennessee; a few occurrences from each group spill into the intervening Cumberlands/Southern Ridge and Valley region. Most occurrences are in West Virginia, Virginia, and Kentucky, with only a few in the other states. Reported from North Carolina, but the report was determined to have been based on introduced plants.
Occurrences Comments
Approximately 64 occurrences are believed extant, although 31 of these are estimated to have poor viability. An additional 28 occurrences are considered historical and 3 are extirpated. It seems unlikely that a large number of additional occurrences remain undiscovered, as this is a very conspicuous and well-known plant.
Threat Impact Comments
Euonymus scale (Unaspis euonymi) is a major threat in Kentucky and a threat of as-yet undetermined magnitude elsewhere in the range. The scale has been observed on P. canbyi in Virginia (T. F. Wieboldt pers. comm. to T. Littlefield 2009), may occur on P. canbyi in West Virginia (no confirmed observations) (E. Byers pers. comm. 2009), and has not yet been observed on P. canbyi in Ohio (R. Gardner pers. comm. to T. Littlefield 2009). Deer browsing is believed to be a significant threat in at least West Virginia (E. Byers pers. comm. 2009). The species is protected from many other threats by the nature of its habitat, although quarrying, fires, trampling, and collecting have been cited as threats. In addition, nearby clearcutting may cause erosion of the thin soils and may allow invasive weeds to become established. Grazing has also been noted as a threat at some sites.
Ecology & Habitat

Description

Low evergreen shrub up to 30 cm tall often occurring in patches with smooth serrulate opposite leaves and very small green flowers.

Diagnostic Characteristics

This species is quite unique with its evergreen, opposite leaves, and low shrubby habit. The only other North American species in the genus Paxistima is found exclusively in the western United States. Among Celastraceae, this is the only evergreen species in the region.

Habitat

Associated with bluffs and cliffs of limestone or dolomite, usually growing in shallow soils that form over these substrates. These somewhat open to wooded areas are typically on the upper sections of steep slopes, often above major streams. The lower slopes often support dense hardwood or pine forests. The species may prefer northern aspects (E. Thompson, pers. comm., 1996).

Ecology

KY -- Dry rocky woods, Limestone ridges (Fort Payne formation, Newman limestone), bluffs and cliffs. Some sites may have a substantial litter layer, others are on ridges that are exposed to high winds. Associated species include Acer saccharum, Carex, Diospyros virginiana, Fraxinus quadrangulata, Juniperus virginiana, Nepeta cataria, Ostrya, Pellaea atropurpurea, Phlox subulata, Pinus virginiana, Quercus velutina, Q. stellata, Q. Muehlenbergii, Rhus aromatica, Rosa carolina, Smilax, Solidago aff. harrisii, and Ulmus rubra.

MD -- Occurrences of Paxistima canbyi are on cliff tops, with at least one site on a slope with a northern aspect. The substrate is shaley. Associated plants include Adlumia fungosa, Campanula rotundifolia, Quercus prinus, Tsuga canadensis, and Woodsia ilvensis.

OH -- This species is found on cliffs and bluffs. It occurs in partial shade on neutral organic clays derived from Silurian dolomite (McCance, 1984). Associated plant species include Juniperus virginiana, Quercus prinus, Taxus canadensis, and Thuja occidentalis,

PA -- Occurrences of Paxistima are on Devonian siliceous lime/shales (Hamilton group), Limestone cliffs, The elevation of sites range from 1100 to 1300 ft. Slopes may be steep (30- deg), and aspects are NW. Associated plant species include Acer saccharum, Fraxinus, Magnolia acuminata, Polypodium virginianum, Quercus prinus, Q. rubra, and Tsuga.

TN -- Occurrence is on a shaley bluff with Aquilegia, Carex eburnea, Iris cristata, Juniperus virginiana, Ostrya virginiana, Pinus virginiana, Physocarpus opulifolius, Quercus rubra, Rhus aromatica, Taenidia integerrima, Viburnum acerifolium, and V. prunifolium. Elev. 1350 ft.

VA -- These occurrences are along limestone or dolomite cliffs, with one noted as having a northern aspect. The canopy is closed to open. Paxistima is associated with Thuja.

WV -- Limestone outcrops, cliffs, ridgebacks, barrens, and talus; also shale ledges. One site is unusual in that it appears to be acidic. Elevations range from 1000-2400 ft. and aspects included north, west, and SW slopes. Canopies are open. Associated plants include Acer rubrum, Carex, Cornus canadensis, Hepatica, Juniperus, Liriodendron tulipifera, Pinus strobus, Quercus prinus, Q. rubra, Senecio, Thuja occidentalis and Tsuga canadensis.

Reproduction

Reproduction is mainly vegetative (may root from branches to form clones (Strausbaugh & Core, 1978; Stoutmire, W. from Terwilliger, 1991). It has been observed to set fruit in Kentucky and West Virginia. This plant does not self pollinate (Stoutmire, 1991) indicating that more than one genetic type occurs at this location.
Terrestrial Habitats
Forest/WoodlandWoodland - MixedBarrensCliff
Other Nations (1)
United StatesN2
ProvinceRankNative
PennsylvaniaS1Yes
TennesseeS1Yes
OhioS1Yes
MarylandS1Yes
VirginiaS2Yes
KentuckyS1Yes
West VirginiaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & mining———
3.2 - Mining & quarryingNegligible (<1%)——
4 - Transportation & service corridors———
4.1 - Roads & railroadsNegligible (<1%)——
8 - Invasive & other problematic species, genes & diseases———
8.5 - Viral/prion-induced diseases———
8.5.2 - Named "species" (disease)Large - smallSerious - moderateHigh (continuing)

—

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (3)
Virginia (1)
AreaForestAcres
Three SistersGeorge Washington National Forest8,149
West Virginia (2)
AreaForestAcres
Dolly Sods Roaring PlainMonongahela National Forest13,392
North Mountain HopevilleMonongahela National Forest6,525
References (23)
  1. Braun, E.L. 1941. A new Station for Paxistima canbyi. Castanea 6: 52.
  2. Braun, L.E. 1961. The woody plants of Ohio. Ohio State Univ. Press, Columbus, Ohio. 362 pp.
  3. Byers, Elizabeth. Personal communication. Project Ecologist, West Virginia Natural Heritage Program, West Virginia Department of Natural Resources, Elkins WV.
  4. Clarkson, R.B. et al. 1981. Rare and endangered vascular plant species in West Virginia. U.S. Fish and Wildlife Service. 76 pp.
  5. Flora of North America Editorial Committee (FNA). 2016. Flora of North America north of Mexico. Vol. 12. Magnoliophyta: Vitaceae to Garryaceae. Oxford Univ. Press, New York. xxiv + 603 pp.
  6. Gardner, Rick. Personal communication. Heritage Botanist, Ohio Natural Heritage Program, Division of Natural Areas & Preserves, Ohio Department of Natural Resources, Columbus, OH.
  7. Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.
  8. Grund, Steve. Personal communication. Botanist, Pennsylvania Natural Heritage Program/Western Pennsylvania Conservancy, Pittsburgh, PA.
  9. Harmon, P. J. No Date. Element Rank Specifications for Rare Plants of West Virginia.
  10. 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.
  11. Kral, R. 1983c. A report on some rare, threatened, or endangered forest-related vascular plants of the South. U.S. Dept. of Agriculture Forest Service Technical Publication R8-TP2, Athens, GA. 1305 pp.
  12. Littlefield, Tara. Personal communication. Botanist, Kentucky Natural Heritage Program, Kentucky State Nature Preserves Commission, Frankfort , KY.
  13. Ludwig, Chris. Botanist, Virginia Division of Natural Heritage, Dept. of Conservation &amp; Recreation, Main Street Station, Richmond, VA
  14. McCance, R.M., Jr., and J.F. Burns, eds. 1984. Ohio endangered and threatened vascular plants: Abstracts of state-listed taxa. Division Natural Areas and Preserves, Ohio Dept. Natural Resources, Columbus. 635 pp.
  15. Morse, Larry E. Personal Communication. North American Botanist, NatureServe, Arlington, VA. Formerly Chief Botanist, The Nature Conservancy, Arlington, VA.
  16. Navaro, A.M., and W.H. Blackwell. 1990. A revision of Paxistima (Celestraceae). Sida 14(2): 231-249.
  17. Ogle, D.W. 1991c. Virginia's Endangered Species: Proceeding of a Symposium. Coordinated by Karen Terwilliger. Nongame and Endangered Species Program, Virginia Dept. of Game and Inland Fisheries. The McDonald and Woodward Publishing Co. Blacksburg, VA.
  18. Stoutmaire, W.P. 1991. Report #910533 on <i>Paxistima canbyi</i>. Ohio Div. of Natural Resources.
  19. Strausbaugh, P.D., and E.L. Core. 1978. Flora of West Virginia. Seneca Books, Inc., Grantsville, WV. 1079 pp.
  20. Townsend, J. Personal communication. Staff Botanist. Virginia Division of Natural Heritage. Department of Conservation and Recreation. Richmond, VA.
  21. White, D. 1996. Inventory for Paxistima canbyi (Mountain Lover) in Kentucky. Kentucky State Nature Preserves Commission, Frankfort, Kentucky.
  22. White, Deborah. Personal communication. Botanist, Kentucky Nature Preserves Commission, Frankfort, KY.
  23. Wieboldt, Thomas F. Personal communication. Curator, Massey Herbarium (VPI), Department of Biological Sciences, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, VA.