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Montana Field Guide

Montana Field Guides

Small Yellow Lady's-slipper - Cypripedium parviflorum
Other Names:  Cypripedium calceolus

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S3S4
(see State Rank Reason below)
C-value: 9

Agency Status


External Links

State Rank Reason (see State Rank above)
Many occurrences known from the western half of the state, including a dozen or so historical or poorly documented sites. Many occurrences have small population numbers, though approximately two dozen occurrences are moderate to large populations. Populations occur on variety of federal, state and private ownerships with varied land uses and management. A variety of land uses and activities, including development, livestock grazing and timber harvesting may have detrimental impacts to populations. However, yellow lady's-slipper appears to be tolerant to some disturbances at low levels and the number of populations scattered over a wide area reduces the risk to the species. A loss of populations or a significant decline in numbers may warrant a re-listing as a Species of Concern in Montana, and populations should continue to be monitored on a semi-regular basis. Moderate to large occurrences should be managed to maintain habitat and viable population numbers.
  • Details on Status Ranking and Review
    Small Yellow Lady's-slipper (Cypripedium parviflorum) Conservation Status Review
    Review Date = 01/07/2013
    View State Conservation Rank Criteria
    Population Size

    Score1-2 - Small to Moderate. Population size is imprecisely known but is believed to be >2,000 individuals and <100,000 individuals.

    Range Extent

    Score0-1 - Widespread to Sporadically Distributed: Species has a distribution in the state such that it is borderline in its classification or its distribution is too imprecisely documented to place it in one class.

    Area of Occupancy

    Score0 - High: Occurs in >25 Subwatersheds (6th Code HUC’s).

    Environmental Specificity

    Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).


    Score0-2 - Stable to Moderate Declines:

    CommentTrend data are largely unavailable. Habitat generally appears to be stable and it does not appear likely that severe declines have occurred. Some declines and/or loss of habitat has almost certainly occurred in the last 3 decades. Additional declines and/or loss of habitat at some locations across the species' range in Montana is likely.


    Score1-2 - Medium to High.

    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 severe. Due to the proximity of some locations to development, negative impacts at a few locations appears likely.

    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 5 to 10 total points scored out of a possible 19.

General Description
Small Yellow Lady's-slipper is a perennial with leafy stems 15-40 cm tall, which arise from short rhizomes. The elliptic leaves are 6-7 cm long and sheath the stem; foliage is lightly pubescent and usually glandular. The 1-2 yellow flowers are subtended by an erect leafy bract, which is often longer than the inflorescence. The narrow sepals reach up to 4 cm long, and are wavy-margined or slightly twisted. One petal is strongly pouch-shaped and often purple-dotted; the other 2 petals are united into one that is similar to the sepals but slightly longer. The fruit is an elliptic capsule bearing thousands of tiny seeds.

Flowering in May-June, fruiting in July.

Diagnostic Characteristics
Distinguishing characteristics of Cypripedium parviflorum include: small, yellow pouch or slipper petal (2-2.5 cm long), sepals conspicuously twisted, and deep reddish brown. This is the only yellow-flowered lady's-slipper in Montana. A hybrid between C. parviflorum and C. montanum can occur where the two species meet, with intermediate characteristics.

Species Range
Montana Range Range Descriptions


Range Comments
AK to NL south to NV, AZ, NM, MO, GA, Europe (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 252

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Fens, damp mossy woods, seepage areas, and moist forest-meadow ecotones in the valley to lower montane zones.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see

  • 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?
    • Arditti, J., J.D. Michaud and P.L. Healey. 1979. Morphometry of orchid seeds. I. Paphiopedilum and native California and related species of Cypripedium. American Journal of Botany 66(10):1128-1137.
    • Chadde, Steve. Sensitive Plant Survey, Pinkham Analysis Area, Kootenai National Forest. Unpublished Report, 26 Pp. Plus Appendices.
    • Harms, V.L. 1973. New record for the yellow lady's slipper orchid, Cypripedium calceolus L. subsp. parviflorum (Salisb.) Hult., from Alaska. Rhodora 75:491.
    • Hoitsma, T. 1992. Sensitive Plant Survey, Fortine Ranger District, Kootenai National Forest. [Unpublished Report] 65 pp. plus appendices.
    • Jones, W. W. 1901. Preliminary flora of Gallatin County. M.S. Thesis. Bozeman, MT: Montana State College. 78 pp.
    • Lesica, P. 1986. Vegetation and flora of Pine Butte fen, Teton County, Montana. The Great Basin Naturalist 46(1): 22-32.
    • Lesica, P. 1991. The Rare Vascular Plants of Pine Butte Swamp Preserve. Unpublished Report to the Nature Conservancy. 15 Pp.
    • Linden, B. 1980. Aseptic germination of seeds of northern terrestrial orchids. Ann. Bot. Fennici 17:174-182.
    • Nekola, J. C. 1990. Rare Iowa plant notes from the R. V. Drexler Herbarium. Journal of the Iowa Academy of Science 97(1): 55-73.
    • St-Arnaud, M. and D. Barabe. 1989. Comparative analysis of the flower vascularization of some Cypripedium species (Orchidaceae). Lindleyana 4(3):146-153.
    • Vanderhorst, J.P. 1996. Status report on sensitive lady's slipper orchids (Cypripedium calceolus var. parviflorum and Cypripedium passerinum) on the Kootenai National Forest. Unpublished report to the Kootenai National Forest. Montana Natural Heritage Program, Helena, MT 27 pp. plus appendices.
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Citation for data on this website:
Small Yellow Lady's-slipper — Cypripedium parviflorum.  Montana Field Guide.  .  Retrieved on , from