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Round-leaved Orchis - Amerorchis rotundifolia
Other Names:
Orchis rotundifolia
State Rank Reason (see State Rank above)
In Montana, this species is restricted to the Rocky Mountain Front, Bob Marshall Wilderness Complex, Swan Valley, and the northwest corner of the state. Several dozen occurrences are known in Montana with many being large, healthy populations. However, data on population trends and impacts due to threats are lacking.
- Details on Status Ranking and Review
Population Size
Score1 - Moderate: Generally 10,000-100,000 individuals.
CommentBased upon available data, population size is probably in the lower end of the 10,000-100,000 range.
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.
Area of Occupancy
Score1 - Moderate: Generally occurring in 11-25 Subwatersheds (6th Code HUC’s).
Environmental Specificity
Score1-2 - Moderate to High.
Trends
Score0-1 - Stable to Minor Declines:
CommentTrend data are largely unavailable. Habitat generally appears to be stable and it does not appear likely that severe declines have occurred, though it is possible that minor declines may be occuring across the species' range in Montana.
Threats
Score1 - Medium: 11-30% of the populations are being negatively impacted or are likely to be impacted by one or more activities or agents, which are expected to result in decreased populations and/or habitat quality and/or quantity.
CommentThough impacts may be occurring or likely at some locations, the magnitude or immediacy of threats to the species or its habitat do not appear to be high.
Intrinsic Vulnerability
Score2 - High Vulnerability: Very specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species highly susceptible to extirpation from stochastic events or other adverse impacts to its habitat and very slow to recover.
Raw Conservation Status Score
Score
7 to 9 total points scored out of a possible 19.
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: 177
(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.
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.
- 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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