(Ashe) Fern.
Identity
Unique IDELEMENT_GLOBAL.2.157815
Element CodePDBET020J0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNCritically endangered
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderFagales
FamilyBetulaceae
GenusBetula
SynonymsBetula lenta var. uberAshe
Other Common NamesVirginia roundleaf birch (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.
Taxonomic CommentsBetula uber, known from a single population, differs from the widespread black birch (Betula lenta) in having blunt leaves. It was originally described as a variety of B. lenta (Ashe 1918). Kartesz (1994, 1999) recognizes this as a full species, as does the Flora of North America (1997) and the U.S. Fish and Wildlife Service (formal listing as a threatened species, 1994). Peter Mazzeo, who is familiar with this plant in the field, considers these plants to be best treated as a full species (J.T. Kartesz, pers. comm., 1999). From Weakley et al. (2023): "See Mazzeo (1974), Ogle & Mazzeo (1976), Hayden & Hayden (1984), McAllister & Ashburner (2004), and Ashburner & McAllister (2016) for additional information on this birch and its history. It does not breed "true" and should perhaps be considered a form of B. lenta."
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2021-11-23
Change Date1984-03-02
Edition Date2021-11-23
Edition AuthorsRoth, E. (1987), rev. Maybury/Ludwig (1996), rev. L. Morse (1999), rev. A. Tomaino (2009), Knapp (2021)
Threat ImpactHigh
Range Extent<100 square km (less than about 40 square miles)
Number of Occurrences1 - 5
Rank ReasonsBetula uber is a rare tree known from one occurrence and a single wild plant. It was first noticed in 1918, but this taxon was not seen again until 1975 when the single population (then consisting of 41 trees) was rediscovered in Smyth County, Virginia, U.S.A. Since that time, the number of individuals in the natural, native population has steadily declined from eleven in 1984 to one in 2020. In the early 1980's an aggressive recovery plan, involving planting greenhouse-grown seedlings at various sites, was implemented. Although vandalism initially threatened the recovery program, in 2003, there were 953 planted individuals alive. Whether these trees will be capable of competing and reproducing successfully remains to be seen. Lack of natural reproduction is a major threat.
Range Extent CommentsBetula uber is known from a single site at Cressy Creek in Smyth County, Virginia in the eastern United States.
Occurrences CommentsThe single known natural population was rediscovered in 1975. Between 1984 and 1987, twenty populations of 96 seedlings each were planted on USFS lands (Davis 2006). These populations are not yet clearly established. Natural reproduction where a mast year coincides with suitable habitat seems to be very rare (Davis 2006).
Threat Impact CommentsBetula uber is threatened by the absence of forest openings and exposed mineral soil which seem to be requirements for natural reproduction (Davis 2006). This extremely rare species has been affected by over-collecting of seedlings for cultivation and material for research. Vandalism of restoration efforts has also been a factor (Southern Appalachian Species Viability Project 2002). The present availability of greenhouse-grown seedlings has reduced threats from collecting and vandalism (Davis 2006).