Section II: Species Information - Cypripedium montanum

XI. Cypripedium montanum Dougl. ex Lindl. (mountain lady's slipper orchid)

Area of Application: West Cascades within the area covered by the Northwest Forest Plan.

A. Introduction

Cypripedium montanum is a large, stout, perennial orchid (Orchidaceae). Mountain lady's slipper is the common name most often applied to this species.

Cypripedium montanum is considered to be associated with old-growth habitat, and is classified as a Survey and Manage Strategy 1 and 2 species for the western Cascades province only under the FSEIS/ROD (USDA Forest Service and USDI Bureau of Land Management 1994a, 1994b). The Oregon Natural Heritage Program (1998) has identified it as a species that is declining in numbers or habitat but is still too common to be proposed as threatened or endangered (List 4) and is considered an Oregon and Washington Bureau Tracking Species under the OR/WA BLM Special Status Plant Policy.

B. Unique Characteristics, Biology, and Ecology

The following is a technical description of Cypripedium montanum:

Stem (1) 2-6 dm tall, glandular-pubescent, leafy throughout; leaves broadly elliptic to ovate-elliptic, 5-15 cm long, up to 7 cm broad, somewhat glandular-pubescent, sessile and usually sheathing; flowers usually 2, but occasionally 1 or 3, each subtended and usually exceeded by an erect leaf-like bract; sepals and petals light to rather deep brownish-purple, narrowly to broadly lanceolate, usually more or less twisted and wavy, the upper sepal mostly (3) 4-5 cm long, the lower pair not quite so long, fused except for the slender terminal toothlike lobes; petals slightly longer than the sepals (up to 6.5 cm long); lip obovoid and strongly pouched, 2-3 cm long, dull white to purplish-tinged, usually purplish-veined; staminodium up to 10 (12) mm long, yellowish-white and usually purplish-spotted, ovate, only rarely auriculate at the base (Hitchcock et al. 1969).

Flowering usually occurs from May to early July, with sites at lower elevations blooming earlier than sites at higher elevations. The shape of C. montanum flowers and the position of the reproductive structures suggests that they have coevolved with a particular pollinator to achieve cross-fertilization (Leur 1969; Barker 1983; Harrod 1994). It is suspected that a species of bee is the pollinator for C. montanum. Specific fungi are required for germination and establishment of new C. montanum seedlings; presence of these fungi may be more ecologically important than specific site characteristics (e.g., elevation, moisture) (USDA Forest Service and USDI Bureau of Land Management 1994b).

Cypripedium montanum often grows sympatrically with C. fasciculatum and probably shares similar biological requirements. Research done on Cypripedium fasciculatum (Harrod et al. 1996; Harrod and Knecht 1994) indicates that mid to late-successional forest communities are optimum habitat for C. fasciculatum, possibly because the required fungal symbiont(s) are present in these older communities and not in early successional communities. Because of their sympatry, these findings could also apply to Cypripedium montanum.

The nearly microscopic seeds of C. montanum are produced in large numbers. They are usually waterproof at the time of dispersion and are carried by air or water. The seeds are dependent on mycorrhizae fungi for germination and establishment (Sheviak 1990).

C. montanum likely shares the same growth patterns as other native orchids, which are regularly saprophytic when immature, spending several years in a dependent, subterranean condition before sufficient growth occurs, and stored food accrues for the production of leaves (Case 1987). It is only after this that the plant first appears above ground. Growth is then rapid, and within a season or 2, flowering commences (Curtis 1943). Mature plants appear to require mycorrhizae for proper water uptake and some nutrients (Sheviak 1990). Estimates on the length of time necessary for development of native species from seed to flowering vary considerably. Curtis (1943) calculated an approximate time scale for growth and development of some Cypripedium species of Wisconsin, determining that the length of time until first flowering varied between 8 and 16 years.

Spring growth of orchids arises from overwintering buds that were produced the preceding growing season. Unlike most other plants, however, if new spring growth is destroyed by late frost, foraging animals, or forest management activities, an orchid cannot replace the lost tissues until the following year (Sheviak 1990). Although dormant buds may be present, they will not initiate growth. The root system will remain, and a new bud may form, or a dormant bud will enlarge, but at best the plant will suffer a major setback, and it may die (Sheviak 1990). Cypripedium plants that lose their growth before midsummer will commonly appear the next year but will not bloom (Whitlow 1983). Depending on how severely depleted their energy reserves were, they may require 2 or more subsequent vegetative seasons before blooming (Case 1987; Whitlow 1983).

The historical ecosystem processes that are thought to have provided habitat for this species have been altered. The FSEIS (USDA Forest Service and USDI Bureau of Land Management 1994b) discusses fire suppression as, perhaps, an important factor in the decline of Cypripedium montanum. This is based on site information that indicates the species appears to be doing better in eastern Oregon, and this may be attributable to fire. The greater fire frequency east of the Cascade Range may correlate to the greater number of known sites in the area (USDA Forest Service and USDI Bureau of Land Management 1994b). Additionally, C. montanum seems to persist in areas that have been burned. Recent research on Cypripedium fasciculatum, however, appears to contradict the belief that Cypripediums are fire dependent (Harrod et al. 1996). Their findings were that Cypripedium fasciculatum is a fire-intolerant species, and management of this species probably should not include prescribed fire. C. montanum and C. fasciculatum often grow sympatrically, which would indicate that their habitat requirements may be very similar. Therefore, the role of fire needs to be investigated before it is reintroduced into Cypripedium montanum habitat.

C. Specific Habitat Associations

Cypripedium montanum is found in a broad range of habitats. Specific moisture and temperature regimes may be less critical than the presence of specific symbiotic fungi. It has been observed at elevations ranging from 495 m (1500 ft.) to 2146 m (6500 ft.), although the majority of sites occur between 825-1321 m (2500-4,000 ft.), respectively). Aspects are mainly northerly, occurring on slopes of 25 to 50 percent. Site location data indicates an ability for C. montanum to grow on a wide variety of substrates in wooded communities with 60-80 percent canopy closure. C. montanum is generally found growing in mixed conifers and mixed evergreen/oak woodland plant communities (Franklin and Dyrness 1973). In the southern part of its range, these communities most often consist of Pseudostuga menziesii in combination with one or more of the following: Lithocarpus densiflorus, Arbutus menziesii, Pinus lambertiana, or Pinus ponderosa. In the northern part of its range, these plant communities consist of Pinus ponderosa, Pinus contorta, and Pseudostuga menziesii.

D. Range of Cypripedium montanum

1. Known Range

Cypripedium montanum is found in southern Alaska, British Columbia, Vancouver Island, western Alberta, and south to Montana, Idaho, Wyoming, and northern California. It is not known from the Olympic Peninsula nor west of the Cascade Range crests in Washington, except along the Columbia River Gorge (Hitchcock et al. 1969). In Oregon, it has been documented from the following counties: Baker, Crook, Deschutes, Douglas, Grant, Hood River, Jackson, Jefferson, Josephine, Klamath, Lake, Lane, Marion, Morrow, Umatilla, Union, Wallowa, Wasco, and Wheeler (USDA Forest Service and USDI Bureau of Land Management 1994b).

2. Suspected Range

Populations of this species could be located throughout the range of the Northern Spotted Owl.

E. Timing of Surveys

Cypripedium montanum flowering usually occurs from May to early July, with sites at lower elevations blooming earlier than sites at higher elevations. Surveys should be conducted during the flowering or fruiting period (May through August) when plants are most easily seen and identifiable.

F. Threats

Management Recommendations for C. montanum (Seevers and Lang 1998) identified the following major threats:

Physical disturbance of microhabitat (population sites).

Adverse edge-affects altering interior habitat conditions and microclimate due to fragmentation of habitat.

Decrease in pollinator abundance.

Collection of plants.

REFERENCES

Barker, L. M. 1983. Botanical investigation and management guidelines for Cypripedium species. USDA, Forest Service, Region 5, Klamath NF.

Case, F. Jr. 1987. Orchids of the western Great Lakes region. Cranbook Institute of Science. Bulletin 48.

Curtis, J. 1943. Germination and seedling development in five species of Cypripedium L. American Journal of Botany. March 199-206.

Franklin, J. F. and C. T. Dyrness. 1973. Natural Vegetation of Oregon and Washington. Pacific Northwest Forest and Range Experiment Station, U.S. Department of Agriculture Forest Service, General Technical Report PNW-8, Portland, OR

Harrod, R. J. 1994. Characteristics of Cypripedium fasciculatum seeds. Northwest Science 68(2).

Harrod, R. J. and D. Knecht. 1994. Preliminary observations of the reproductive ecology of Cypripedium fasciculatum. Northwest Science 68(2).

Harrod, R. J., D. Knecht, E. Kuhlmann, M. Ellis, and R. Davenport. 1996. Effects of the Rat and Hatchery Creek fires on four rare plant species. Unpublished paper on file at U.S.D.A. Forest Service, Region 6, Wenatchee National Forest, Leavenworth Ranger District

Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1969. Vascular Plants of the Pacific Northwest. University of Washington Press, Seattle, WA.

Luer, C. A. 1969. The genus Cypripedium in North America. American Orchid Society Bulletin, October: 903-908.

Oregon Natural Heritage Program. 1998. Rare, Threatened and Endangered Species of Oregon. Oregon Natural Heritage Program, Portland, Oregon. 92 pp.

Seevers, J. and F. Lang 1998. Management Recommendations for Mountain Lady's Slipper (Cypripedium montanum Douglas ex Lindley). Unpublished manuscript.

Sheviak, C. J. 1990. Biological considerations in the management of temperate terrestrial orchid habitats. New York State Museum Bulletin 471, pp.194-196.

USDA Forest Service and USDI Bureau of Land Management. 1994a. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Portland, Oregon.

USDA Forest Service and USDI Bureau of Land Management. 1994b. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Appendix J2, Results of Additional Species Analysis. Portland, Oregon.

Whitlow, C. E. 1983. Cypripedium culture. Pp. 25-31 in E. H. Paxton (ed.). Proceedings of the North American Terrestrial Orchids Symposium II and Lectures. Michigan Orchid Society, Livonia, MI.