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Wedge-leaf Saltbush - Atriplex truncata
State Rank Reason (see State Rank above)
Known from two extent occurrences; one in the Centennial Valley and the other near Warm Springs. Also, known historically from four collections in the western half of the state. Additional population and trend data are needed to better evaluate the species' vulnerability.
- Details on Status Ranking and Review
Population Size
Score1-2 - Small to Moderate. Population size is imprecisely known but is believed to be >2,000 individuals and <100,000 individuals.
CommentPopulation estimates are imprecise but appear to be at least several thousand plants.
Range Extent
Score1 - Peripheral, Disjunct or Sporadic Distribution in MT: Widespread species that is peripheral, disjunct or sporadically distributed within MT such that it occurs in <5% of the state (<7,500 sq. miles or the combined area of Beaverhead and Ravalli Counties) or is restricted to 4-5 sub-basins.
CommentPeripheral and sparsely distributed in western Montana.
Area of Occupancy
Score3 - Very Low: Generally occurring in 3 or fewer Subwatersheds (6th Code HUC’s).
CommentRecently documented/surveyed sites are clustered in two locations in Deerlodge and Beaverhead Counties. Other documented locations in Montana are based upon historical collections. Additional extant occurrences may exist in other watersheds.
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
Score0-2 - Stable to Moderate Declines:
CommentTrends data are lacking though it does not appear likely that severe declines have occurred in the recent past.
Threats
Score0-1 - Low to Medium.
CommentThreats to the species appear to be minimal.
Intrinsic Vulnerability
Score0-1 - Low to Moderate Vulnerability.
Raw Conservation Status Score
Score
6 to 11 total points scored out of a possible 19.
General Description
Wedge-leaved Saltbush is an annual with simple to branched stems that are 10-100 cm tall. The alternate, wedge-shaped to oval leaves, 15-40 mm long, have entire margins and short petioles. The foliage is sparsely to densely covered with grayish scales that rub off. Small, unisexual flowers are borne in clusters in leaf axils. Male flowers lack petals but have a 5-parted calyx. Female flowers lack both petals and sepals and are subtended by 2 wedge-shaped bracts which are 2-3 mm long in fruit and which have entire margins but 2-3 low teeth across the top.
Phenology
Flowering and fruiting in August-September.
Diagnostic Characteristics
A. truncata is similar to A. argentea, A. powellii, and A. rosea, but can be distinguished by the wedge-shaped flower bracts that are 3 mm long or less with smooth faces and a wavy or toothed upper margin.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
In MT from only a few counties in the western third; BC and SK south to CA, NV, UT, and CO (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX; Welsh 2003 in Fl. N. Amer. Vol. 4).
Observations in Montana Natural Heritage Program Database
Number of Observations: 18
(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
Vernally moist, alkaline soil around ponds and along streams in the valleys.
Ecological Systems Associated with this Species
Threats or Limiting Factors
STATE THREAT SCORE REASON
Reported threats to Montana's populations of Wedge-leaf Saltbush are currently assigned as unknown (MTNHP Threat Assessment 2021). Recreation activity and non-native plants are reported to threaten populations, but the severity of expected impacts is not known.
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
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- Culver, D.R. 1994. Floristic analysis of the Centennial Region, Montana. M.Sc. Thesis. Montana State University, Bozeman. 199 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.
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