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Alderleaf mountain-mahogany - Cercocarpus montanus
State Rank Reason (see State Rank above)
This widespread western species is only known in the state from one area of Treasure County where it is reported to be fairly extensive. Additional data on population size and extent are needed to more precisely rank the species.
- Details on Status Ranking and Review
Score1-2 - Small to Moderate. Population size is imprecisely known but is believed to be >2,000 individuals and <100,000 individuals.
CommentEstimated. Population levels are imprecisely known though data describes it as abundant at the known site.
Score3 - Local Endemic or Very Small Montana Range: Generally restricted to an area <10,000 sq. miles (equivalent to the combined area of Phillips and Valley Counties) or <6 Sub-basins (4th code watersheds) Range-wide OR limited to one Sub-basin in Montana
Area of Occupancy
Score3 - Very Low: Generally occurring in 3 or fewer Subwatersheds (6th Code HUC’s).
Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).
ScoreNA - Rank factor not assessed.
Score0-1 - Low to Medium.
Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.
CommentPlants are supposed to reach maturity in 5
to 15 years, produce adundant seed every 1-10 years, though with high rates of non-viable seed.
Raw Conservation Status Score
9 to 11 total points scored out of a possible 16 (Rarity factors and threats only).
Mountain-mahogany is a shrub that reaches up to 2 m high and has smooth, gray or brown bark. The alternate, spoon-shaped leaves, 1-3 cm long, have short petioles, serrated margins on the upper half, and blunt tips. They are dark green and glabrous above but pale and often sparsely hairy beneath. 1-3 flowers are borne on short stalks near the tips of short side branches. The flowers lack petals and consist only of a hairy calyx formed of a tube with 5 reflexed lobes that is 3-6 mm long in bloom but up to 14 mm long in fruit. There are 25-40 stamens. The hairy seeds are up to 12 mm long with tails that are 3-6 cm long.
Our plants are variety montanus.
Flowering in early May.
The combination of simple, serrated, unlobed leaves and hairy, long, plumose fruits distinguish this shrub from all others in our area. The toothed leaves without an incurved margin distinguish this species from the common Cercocarpus ledifolius.
OR to SD, south to CA, AZ, TX and Mexico (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations:
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Open slopes and breaks on the plains.
Threats or Limiting Factors
STATE THREAT SCORE REASON
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).
- Literature Cited AboveLegend: View Online Publication
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.
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