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Dwarf Saw-wort - Saussurea nuda
Other Names:
Saussurea nuda var. densa, Saussurea densa
State Rank Reason (see State Rank above)
Saussurea nuda is restricted to alpine habitat within the Bob Marshall Wilderness and mountains along the Rocky Mountain Front in Montana. Occurrences are scattered and mostly small in size. The small populations make Saussurea nuda vulnerable to extirpation in the state.
Surveys that bring forth current data on distributions, population counts and viability, habitat conditions, and threats are greatly needed. Monitoring is also necessary to assess population trends.
General Description
Dwarf Saw-wort is a dwarf perennial herb that is 5-20 cm high and arising from a woody rootstock. The lance-shaped leaf blades are coarsely toothed, up to 8 cm long, and have a broad petiole. The alternate leaves are crowded on the stem, reduced, and lacking petioles towards the tops. The herbage is covered with long, tangled hairs when young but becomes glabrous with age. The purple flowering heads are borne in a dense cluster subtended by leaves at the top of the stem. The narrow involucral bracts of the heads are 11-15 mm long. All of the flowers are tubular (disk flowers); ray flowers are absent. The achene has a pappus on top.
Our plants are variety densa (Hook.) Hulten.
Phenology
Flowering in July-early August, fruiting in late August.
Diagnostic Characteristics
The clustered, purple, rayless flowering heads, together with the rocky, high elevation habitat, are distinctive. The similar S. weberi occurs in southwest Montana mountains and has broad involucral bracts with rounded tips.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
AK to MT; Asia (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations: 26
(Click on the following maps and charts to see full sized version)
Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Calcareous soil of talus slopes and rocky, open slopes in the alpine zone.
National Vegetation Classification System Groups Associated with this Species
Alpine
Alpine - Sparse and Barren
Alpine - Vegetated
Stewardship Responsibility
Threats or Limiting Factors
Reported threats to Dwarf Saw-wort have not been identified though climate change poses a potential risk to state's populations. The MTNHP conducted a species-level assessment using the Climate Change Vulnerability Index (CCVI) in 2021, which resulted in a Moderate Vulnerable rating to climate change. Climate change including increased ambient temperatures, decreased snowpacks, and increased frequencies and severities of drought could have negative impacts on this species; however, field-based data on the timing and magnitude from climate change is not available.
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.
MTNHP Threat Assessment. 2021. State Threat Score Assignment and Assessment of Reported Threats from 2006 to 2021 for State-listed Vascular Plants. Botany Program, Montana Natural Heritage Program, Helena, Montana.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- 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.
- Watson, T.J. and K.H. Lackschewitz. 1980. The genus Saussurea (Asteraceae-Cynareae) in Montana. Northwest Science 54(2):106-108.
- Web Search Engines for Articles on "Dwarf Saw-wort"
