Regularity: Regularly occurring
Localities documented in Tropicos sources
United States (North America)
Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.
- Hartman, R. L. & B. E. Nelson. 1998. Novelties from North America north of Mexico: A 20-Year Vascular plant Diversity Baseline. 1–51 (mss.). http://www.tropicos.org/Reference/11044
- Flora of North America Editorial Committee, e. 1997. Magnoliidae and Hamamelidae. 3: i–xxiii, 1–590. In Fl. N. Amer. Oxford University Press, New York. http://www.tropicos.org/Reference/24627
- Barnes, B. V. & B. P. Dancik. 1985. Characteristics and origin of a new birch species, Betula murrayana, from southeastern Michigan. Canad. J. Bot. 63: 223–226. http://www.tropicos.org/Reference/11981
Global Range: Only known occurrence is from the shore of a lake in Washtenaw County, Michigan.
Comments: Swamps and edges of bogs and lakes in southern Michigan.
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 1 - 5
Comments: One occurrence located on University of Michigan's forest properties, in Washtenaw County in southern Michigan.
Life History and Behavior
National NatureServe Conservation Status
Rounded National Status Rank: N1 - Critically Imperiled
NatureServe Conservation Status
Rounded Global Status Rank: G1 - Critically Imperiled
Reasons: Betula murrayana is known from a single naturally occurring site in Washtenaw County, Michigan. One one individual remains, of the two originally known there in the 1960's. Propagated plants are maintained in cultivation, and a few that were planted at the original site and another site have reached flowering size. The species may have recently evolved through hybridization.
Global Short Term Trend: Relatively stable (=10% change)
Comments: The one remaining individual has survived. Planted individuals at the site are maturing, and have flowered.
Global Long Term Trend: Increase of 10-25% to decline of 30%
Comments: Of the two plants originally known in the 1960's, only one survives. The species has been propagated from cuttings and seed, and a few planted individuals have reached flowering size, including a few reintroduced to the original site.
Degree of Threat: Very high - high
Comments: The population size is precariously small, with the species known from a single natural occurrence, but no particular other threats have been noted.
Names and Taxonomy
Comments: Fertile species formed through hybridization (Barnes and Dancik, 1985; Flora of North America, 1997).