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Columbia Locoweed - Oxytropis campestris var. columbiana
Other Names:
Oxytropis columbiana
State Rank Reason (see State Rank above)
DRAFT: Requesting feedback on the 2026 revised rank, factors, and State Rank Reason outlined below and in the Conservation Status Rank Report.
Oxytropis campestris var. columbiana is a regional endemic of Montana and Washington. It is extremely rare in Montana, where it occurs in several small populations along the shores of Flathead Lake. Total statewide populations appear to be less than 1,000 plants. Populations are threatened primarily by on-going shoreline development. Existing shoreline development and alteration appear to have extirpated some populations. Recreational use along the shoreline and hydrologic alterations from elevated and managed water levels have also negatively impacted the populations and likely continue to do so. Data to accurately and precisely determine trends are lacking, though poulations have almost certainly declined significantly over the long term and have likely experienced at least minor declines in the recent past.
Survey and monitoring data are greatly needed for assessing the current size and condition of the occurrences and to be able to accurately determine population trends. Surveys of the Flathead Lake shoreline are needed to determine if additional populations exist.
General Description
Columbia Crazyweed is a clump-forming perennial with leafless flower stalks that are 5-30 cm tall, and arising from a branched rootstock. The basal leaves are pinnately compound with mostly less than 17 leaflets, and have membranous stipules that are attached to the petiole for at least 1/2 their length. The greenish to grayish foliage is sparsely to densely covered by hairs. The flower stalks are slightly shorter to much longer than the leaves and bear 5-40 flowers in a spike-like inflorescence. The pea-like flowers are 10-20 mm long. The greenish tubular calyx is covered by grayish to blackish hairs and has five pointed teeth. The white corolla consists of an upper banner petal, two wing petals at the side, and a lower keel petal with purple spots. The pod is two-celled, several seeded, membranous, and 1-2.5 cm long
Phenology
Flowering in late May - early June; fruiting in late June - early July.
Diagnostic Characteristics
OXYTROPIS CAMPESTRIS is most similar to O. SERICEA in having whitish corollas, stipules attached to petioles for most their length, foliage not glandular, leaflets 2-ranked, and inflorescences with more than 4 flowers. OXYTROPIS SERICEA differs by having pods which become bony rather than membranous, and by somewhat larger flowers, averaging 15 mm long. Other subspecies of OXYTROPIS CAMPESTRIS differ by having cream colored flowers with lower petals that lack purple spots, and by leaves mostly with more than 17 leaflets.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
Regional endemic, northeastern Washington and northwestern Montana. Known in Washington from gravelly banks along the Columbia River from the confluence with the Spokane River north to near the Canadian border. Also known form similar habitat along the shores of Flthead Lake, Montana. It is believed that most populations in Washington were destroyed by construction of Grand Coulee Dam. However, populations along the Columbia River may still occur near the Canadian border. Until the mid 1980's only one or two populations were known from around Flathead Lake. Elisens identified Oxytropis populations along the North Folk of the Flathead River as O. columbiana (Peter Lesica's letter to D.R. Harm, 1992).
Observations in Montana Natural Heritage Program Database
Number of Observations: 18
(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
Gravelly shoreline along major lakes and rivers.
National Vegetation Classification System Groups Associated with this Species
Wetland and Riparian
Riparian and Wetland Forest
Ecology
POLLINATORS The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap:
Bombus appositus,
Bombus bifarius,
Bombus centralis,
Bombus fervidus,
Bombus flavifrons,
Bombus melanopygus,
Bombus nevadensis,
Bombus rufocinctus,
Bombus sylvicola,
Bombus occidentalis,
Bombus insularis, and
Bombus kirbiellus (Macior 1974, Bauer 1983, Shaw and Taylor 1986, Williams et al. 2014, Miller-Struttmann and Galen 2014).
Stewardship Responsibility
Threats or Limiting Factors
STATE THREAT SCORE REASON
Reported threats to Montana's population of Columbia Locoweed are of concern because most of the state population is on privately-owned shoreline properties along Flathead Lake (MTNHP Threat Assessment 2021). About one-third of known populations have been destroyed following residential development. Lacking protective process required to develop public-owned properties, extant populations are exposed to ongoing development. The risk of direct displacement of populations and subsequent indirect threats of fragmentation and habitat degradation is likely to increase time.
References
- Literature Cited AboveLegend:
View Online Publication- Bauer, P.J. 1983. Bumblebee pollination relationships on the Beartooth Plateau tundra of Southern Montana. American Journal of Botany. 70(1): 134-144.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.- Miller-Struttmann, N.E. and C. Galen. 2014. High-altitude multi-taskers: bumble bee food plant use broadens along an altitudinal productivity gradient. Oecologia 176:1033-1045.
- 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.
- Shaw, D.C. and R.J. Taylor.1986. Pollination ecology of an alpine fell-field community in the North Cascades. Northwest Science 60:21-31.
- Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Lesica, P. 1988. The occurrence and taxonomic status of Oxytropis campestris var. Columbiana in Montana. Unpublished report.
- 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.
- Web Search Engines for Articles on "Columbia Locoweed"
