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Parry's Fleabane - Erigeron parryi
State Rank Reason (see State Rank above)
Erigeron parryi is a regional endemic that occurs primarily in southwestern Montana with reported occurrences in Wyoming. At least some of Montana's occurrences have large populations, both in numbers and acreage, though many lack precise plant counts. The species' habitat of dry, rocky or gravelly limestone-derived soils is largely intact and in good condition. Therefore, it is presumed that populations are relatively stable. Invasive plant species are present in the surrounding habitats at some occurrences, but data that quantifies an impact is lacking. Changes to the climate could also pose a potential risk to the state's population. Overall, Erigeron parryi remains vulnerable and has a moderate risk of extirpation in the state due to its relative rarity.
Surveys that bring forth current data on distributions, population counts and viability, habitat conditions, and threats are needed. In addition, surveys on lands modelled as predicted suitable habitat are needed to help inform on the status of this species.
General Description
Taprooted perennial with a simple or branched caudex. Stems erect, 2–15 cm. Herbage hirsute with ascending to spreading hairs. Leaves basal and cauline, linear, entire, 1–6 cm long. Heads 1 to 3, radiate. Involucres hemispheric, 4–9 mm high; phyllaries in 1 or 2 series, densely hirsute with white-septate hairs, minutely glandular. Rays 20 to 40, white, usually erect; ligules 5–8 mm long. Disk corollas 2–4 mm long. Achenes ca. 2 mm long (
Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Phenology
Flowering occurs in June and early July.
Diagnostic Characteristics
Erigeron radicatus has smaller heads and disk flowers. Erigeron ochroleucus has appressed hair on the stems, and sparsely hariy leaves; old leaf bases are generally not apparent on the caudex. Spreading hairs on the stems of E. pumilus are about 1 mm long.
Erigeron parryi was first described over 100 years ago based on a single collection made by Frank Tweedy along Grasshopper Creek in Beaverhead County, Montana. Over 50 years ago Arthur Cronquist recognized E. parryi in his monograph on the genus Erigeron (Cronquist 1947). He stated that the species was similar to E. ochroleucus, but the hair of leaves and stems was strikingly different. He hinted that E. parryi might be better considered a variety of E. ochroleucus, but since there was still only one collection, he did not formally propose a new nomenclatural combination. Eight years later Cronquist merged E. parryi into E. ochroleucus, stating that it was a rare form with spreading-hairy herbage (Cronquist 1955). Since that time several additional populations of E. parryi have been located in southwest Montana.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
Endemic to southwest Montana.
Observations in Montana Natural Heritage Program Database
Number of Observations: 40
(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
Erigeron parryi occurs on skeletal, limestone-derived soils of ridge crests, slopes and outcrops at 4,500-7,000 feet. Associated vegetation is sparse and dominated by cushion plants, other low forbs and bluebunch wheatgrass. Dominant vegetation in nearby areas with more developed soils is sagebrush steppe or juniper woodland.
National Vegetation Classification System Groups Associated with this Species
Forest and Woodland
Low Elevation - Xeric Forest and Woodland
Montane - Subalpine Forest and Woodland
Shrubland
Foothills - Montane Shrubland
Sagebrush Shrubland
Grassland
Lowland - Prairie Grassland
Ecology
Erigeron parryi is a small plant that occupies habitats with sparse vegetation, suggesting that it is not tolerant of competition.
POLLINATORS The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap:
Bombus bifarius,
Bombus centralis,
Bombus fervidus,
Bombus flavifrons,
Bombus huntii,
Bombus melanopygus,
Bombus mixtus,
Bombus rufocinctus,
Bombus occidentalis, and
Bombus insularis (Thorp et al. 1983, Wilson et al. 2010, Colla and Dumesh 2010, Koch et al. 2012).
Management
At least two populations of Parry's fleabane occur in historic mining districts (Grasshopper Creek, Silver Star). Road construction and other mining-related activities could pose future threats. All known populations are subject to livestock grazing; however, it is unlikely that these small forbs are palatable, and the sparsely vegetated habitat is probably not frequented by livestock.
Stewardship Responsibility
Threats or Limiting Factors
Parry's Fleabane is known from a limited number of occurrences, in hich its rarity puts the species at a greater risk for state extirpation. Invasive plant species occur near to established populations, but data on their impact is lacking. Climate change poses a potential risk to the population. The MTNHP conducted a species-level assessment using the Climate Change Vulnerability Index (CCVI) in 2021, which resulted in a Moderately 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 the species; however, field-based data on the timing and magnitude from climate change is not available.
References
- Literature Cited AboveLegend:
View Online Publication
Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141:39-68.- Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the western United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 143 p.
- 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.
- Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
- Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Lesica, P. 2005. The resurrection of Erigeron parryi (Asteraceae). Brittonia. 57 (1): 47-54.
- 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.
- Nesom, Guy L. 2004. Taxonomic Reevaluations in North American Erigeron (Asteraceae: Astereae). SIDA 21(1): 19–39.
- Web Search Engines for Articles on "Parry's Fleabane"
