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Round-leaved Orchis - Amerorchis rotundifolia
Other Names:
Orchis rotundifolia
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.
Amerorchis rotundifolia is a relatively rare orchid in Montana, restricted to fens and wetlands in northwest and north-central Montana on both sides of the Continental Divide. Population levels are imprecisely known though they appear likely to be over 10,000 plants. Population trends are undocumented though they seem likely to be relatively stable or experiencing only minor declines in the recent past as the habitat is largely intact and stable. Reported threats, inlcuding invasive species, livestock grazing and flower picking by people have been reported at one or more locations though these threats are not widespread nor currently having/expected to have a severe impact. The species is also rated as "Moderatly Vulnerable" to climate change impacts.
Monitoring at a subset of populations is needed to be able to determine potential population trends.
General Description
Round-leaved Orchis is a glabrous, rhizomatous perennial with a single sub-basal leaf and a stem 10-20 cm tall. Leaf is elliptic to orbicular with a rounded tip, and is up to 10 cm long. The few to several flowers terminate the stem in a narrow inflorescence. There are 3 white to pale pink sepals. The upper is hood-shaped, 6-10 mm long, and slightly larger than the lateral ones; the 2 upper petals are narrowly lance-shaped. The large, lower petal (lip) is up to 9 mm long, white, spotted with purple, and deeply 3-lobed with a pair of lateral lobes and a notched lower one. The capsule is elliptic and contains thousands of tiny seeds.
Phenology
Flowering in late June-early July.
Diagnostic Characteristics
This species is easy to recognize by the single leaf and distinctive flower. Calypso bulbosa also has a single leaf but the pink flowers are solitary and much larger.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
AK to Greenland south to WY, MI, NY (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Observations in Montana Natural Heritage Program Database
Number of Observations: 214
(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
Spruce forest around seeps or along streams, often in soil derived from limestone.
National Vegetation Classification System Groups Associated with this Species
Wetland and Riparian
Peatland
Riparian and Wetland Forest
Riparian Shrubland
Stewardship Responsibility
Threats or Limiting Factors
STATE THREAT SCORE REASON
Reported threats to Montana’s populations of Round-leaved Orchis are attributed to noxious weeds, livestock use, and recreational use (MTNHP Threat Assessment 2021). Several populations are found in the vicinity of noxious weed populations, within grazing allotments, and along hiking trails. Impacts from individual threats are relatively minor. However, co-occurring threats are ongoing in the vicinity of several populations, and these are known to inflict stronger impacts. Potential threats from people collecting Round-leaved Orchis are acknowledged, but the severity of impacts related to collection activity 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.
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?- Chadde, Steve. Sensitive Plant Survey, Pinkham Analysis Area, Kootenai National Forest. Unpublished Report, 26 Pp. Plus Appendices.
- Fertig, W. and G. Jones. 1992. Plant communities and rare plant species of the Swamp Lake Botanical Area, Clark's Fork Ranger District, Shoshone National Forest. Unpublished report to the Shoshone National Forest. Challenge Cost Share Agreement No. CSA-2-91-14-0001. Wyoming Natural Diversity Database. 113+ pp.
- Handley, J. and B. Heidel. 2005. Amerorchis rotundifolia (Banks ex Pursh) Hultén (roundleaf orchid): a technical conservation assessment. USDA Forest Service, Rocky Mountain Region, Species Conservation Project. 37 p.
- Hoitsma, T. 1992. Sensitive Plant Survey, Fortine Ranger District, Kootenai National Forest. [Unpublished Report] 65 pp. plus appendices.
- 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.
- Shelly, J.S. 1988. Status review of Orchis [Amerorchis] rotundifolia, U.S. Forest Service, Region 1, Flathead and Lewis & Clark National Forests, Montana. Unpublished report. Montana Natural Heritage Program, Helena, MT 59 pp.
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