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Rock-tansy - Sphaeromeria capitata
Other Names:
Tanacetum capitatum, Artemisia capitata
Native Species
Global Rank:
G4
State Rank:
S4
(see State Rank Reason below)
C-value:
Agency Status
USFWS:
USFS:
BLM:
External Links
State Rank Reason (see State Rank above)
This species is a regional endemic with limited distribution in limestone foothills of southwest Montana (upper Beaverhead River drainage) and Pryor Mts - Big Horn Canyon. It is reported to be locally common in the Big Horn Canyon area (Lesica & Shelly, 1991)
- Details on Status Ranking and Review
Population Size
Score0-1 - Moderate to Large: Population size is imprecisely known but is believed to be >10,000 individuals.
Range Extent
Score2 - Regional or State Endemic or Small Montana Range: Generally restricted to an area <100,000 sq. miles (equivalent to 2/3 the size of Montana or less) or Montana contributes 50% or more of the species’ range or populations OR limited to 2-3 Sub-basins in Montana.
Area of Occupancy
Score1 - Moderate: Generally occurring in 11-25 Subwatersheds (6th Code HUC’s).
Environmental Specificity
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).
Trends
ScoreNA - Rank factor not assessed.
Threats
Score0-1 - Low to Medium.
Intrinsic Vulnerability
Score0 - Low Vulnerability: Species does not have any unusual or specific life history or biological attributes or limted reproductive potential which makes it susceptible to extirpation from stochastic events or other adverse impacts to its habitat and thus slow to recover.
Raw Conservation Status Score
Score
4 to 6 total points scored out of a possible 16 (Rarity factors and threats only).
General Description
Stems erect, 2–15 cm. Leaves 8–25 mm long, deeply lobed into linear segments. Inflorescence capitate. Involucre 2–3 mm high; phyllaries 5 to 8, tomentose. Disk corollas 1–3 mm long. Achenes 1–2 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Phenology
Flowers from late May through early July.
Diagnostic Characteristics
Recent research supports the placement of Sphaeromeria in Artemisia (Garcia et.al. 2011).
Species Range
Montana Range
Range Descriptions
Native
Range Comments
This species is known from Wyoming, southwestern Montana, northwestern Colorado, and disjunct onto the Utah Plateaus in Garfield Co, Utah (Cronquist et al. 1994).
Observations in Montana Natural Heritage Program Database
Number of Observations: 76
(Click on the following maps and charts to see full sized version)
Map Help and Descriptions
Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Shallow, limestone-derived soil on rock outcrops in exposed sagebrush grassland, desert shrubland, and juniper woodland in the valley and foothill zones.
Ecological Systems Associated with this Species
Stewardship Responsibility
References
- 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?- Garcia, Sònia, Teresa Garnatje, E. Durant McArthur, Jaume Pellicer, Stewart C. Sanderson, and Joan Vallès. 2011. Taxonomic and Nomenclatural Rearrangements in Artemisia Subgen. Tridentatae, Including a Redefinition of Sphaeromeria (Asteraceae, Anthemideae). Western North American Naturalist. 71 (2): 158-163.
- Lesica, P. and P.L. Achuff. 1992. Distribution of vascular plant species of special concern and limited distribution in the Pryor Mountain desert, Carbon County, Montana. Unpublished report to the Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 105 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
- Vanderhorst, J.P. and P. Lesica. 1995a. Sensitive plant survey of the Tendoy Mountains in the Beaverhead National Forest, Beaverhead County, Montana. Unpublished report to the Bureau of Land Management, Butte District. Montana Natural Heritage Program, Helena, MT. 59 pp. plus appendices.
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