Britt.
Identity
Unique IDELEMENT_GLOBAL.2.160003
Element CodePDRAN08010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderRanunculales
FamilyRanunculaceae
GenusClematis
Other Common NamesAddison's leather flower (EN)
Concept ReferenceKartesz, 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 Method Rank calculation - Biotics v2
Review Date2021-03-15
Change Date2021-03-15
Edition Date2020-03-25
Edition AuthorsNancy E. Van Alstine., rev. Ludwig/Maybury (1996), rev. Nordman, C. (2012), rev. L. Oliver (2020)
Threat ImpactVery high - high
Range Extent250-1000 square km (about 100-400 square miles)
Number of Occurrences6 - 20
Rank ReasonsClematis addisonii is endemic to western Virginia, U.S.A., where it is known now from 3 counties and may be restricted to areas underlain by Elbrook Formation dolomite. Eleven populations are known extant in the past 2 decades (1992 - 2011), and many of these are threatened by development, invasive species and habitat fragmentation. There are eight occurrences that are historical and last seen over 40 years ago.
Range Extent CommentsClematis addisonii is known only from the counties of Montgomery, Botetourt, and Roanoke in the Ridge and Valley physiographic province of western Virginia in the United States. There is only one extant occurrence in Roanoke County. It was historically known from Rockbridge County. If historical occurrences are excluded, range extent is 699 sq km.
Occurrences CommentsThere are eleven occurrences documented in the past two decades (1992 - 2011).
Threat Impact CommentsThis species is threatened by development pressures, road widening projects, grazing, deer browsing, canopy closure (Copenheaver et al. 2006), drought and quarry operations, invasive plants, land-use conversion, and habitat fragmentation (J. Townsend, pers. comm., 2020, Southern Appalachian Species Viability Project 2002). A proposed highway connecting Blacksburg with Roanoke does not directly threaten the known populations, but additional field survey work would likely locate populations that are in the corridor. Urban expansion in the Blacksburg and Christiansburg Area may become increasingly severe in the future but is currently a low level threat (J. Townsend, pers. comm., 2021). Canopy closure of woodlands succeeding into forests is a threat, as the species thrives at sites with a small tree canopy and not a dense canopy forest.