Betula murrayana B.V. Barnes & Dancik:
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.

Mich.

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Only known occurrence is from the shore of a lake in Washtenaw County, Michigan.

Trees , to 15 m; trunks usually several. Bark of mature trunk and branches dark red to reddish brown, smooth, close; lenticels pale, conspicuous, horizontally expanded. Twigs with taste and odor of wintergreen when crushed, glabrous to sparsely pubescent, covered with small resinous glands. Leaf blade ovate with 7--10 pairs of lateral veins, 5--11 × 3--6 cm, base cuneate, margins sharply and obscurely doubly serrate, apex acute or only slightly acuminate; surfaces abaxially sparsely pubescent to glabrous. Infructescences erect, ovoid, 2--4 × 1.5--3 cm, remaining intact for a period after release of fruits in late fall; scales sparsely pubescent to glabrous, lobes ascending, branching at middle, slightly unequal in length. Samaras with wings narrower than body, broadest near summit, not extended beyond body apically. 2 n = 112.

Wet, swampy forests containing Betula pumila ; of conservation concern; 0--300m.

Comments: Swamps and edges of bogs and lakes in southern Michigan.

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.

Flowering late spring.

United States

Rounded National Status Rank: N1 - Critically Imperiled

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.

Comments: The population size is precariously small, with the species known from a single natural occurrence, but no particular other threats have been noted.

Betula murrayana is an octoploid derivative of Betula × purpusii (= B . alleghaniensis Britton × B . pumila Linnaeus) (B. V. Barnes and B. P. Dancik 1985). It is intermediate between B . alleghaniensis and B . pumila in most vegetative features, but in characters such as leaf size, it approaches B . alleghaniensis .

Comments: Fertile species formed through hybridization (Barnes and Dancik, 1985; Flora of North America, 1997).