Cypripedium californicum 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Plantae Tracheophyta Liliopsida Asparagales Orchidaceae

Scientific Name: Cypripedium californicum A.Gray
Common Name(s):
English California Lady's Slipper

Assessment Information [top]

Red List Category & Criteria: Endangered B2ab(ii,iii,iv,v) ver 3.1
Year Published: 2014
Date Assessed: 2013-03-15
Assessor(s): Rankou, H.
Reviewer(s): Fay, M. & Sharma, J.

Cypripedium californicum is restricted in range occurring only in California and Oregon with small subpopulations of less than 10 mature individuals and rarely larger subpopulations. The area of occupancy of the species is 194 to 450  kmbelow the 500 km2 threshold for Endangered and is known from four locations. C. californicum is under numerous threats especially habitat loss and disturbance of its restricted range due to urbanization, clear-cutting, suppression of natural disturbance regimes, logging practices, accidental trampling, climate change, mining activities and collection which cause a continuing decline of the species on the estimated locations and the destruction of some subpopulations (e.g. Marin County population is already destroyed). Therefore, C. californicum is assessed as Endangered (EN)

Geographic Range [top]

Range Description:

Cypripedium californicum is restricted in range, occurring only in California and Oregon, USA. C. californicum specifically occurs in Oregon (Josephine and Curry Counties) and in California (in Butte, Del Norte, Humboldt, Mendocino, Marin (extinct there), Plumas, Shasta, Siskiyou, Sonoma and Trinity Counties).

The extent of occurrence (EOO) is estimated at 112,805 km² and the area of occupancy (AOO) is estimated at 192 to 450 km².

The species can be found between 450 and to 1,000 m altitude.

Sources: Cribb 1997, Frosch and Cribb 2012, Coleman 1989, and Kartesz 1994.

Countries occurrence:
United States (California, Oregon)
Additional data:
Estimated area of occupancy (AOO) - km2:192-450,204Continuing decline in area of occupancy (AOO):Yes
Estimated extent of occurrence (EOO) - km2:112805
Number of Locations:4
Lower elevation limit (metres):450
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]


Cypripedium californicum usually occurs in small subpopulations with less than 10 mature individuals and rarely more than 1,000 individuals. The trend of the population is decreasing; the population in Marin County is already destroyed due to many threats (Coleman 1989, Kartesz 1994).

Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Continuing decline in subpopulations:Yes

Habitat and Ecology [top]

Habitat and Ecology:

Cypripedium californicum occurs in a restricted habitat of serpentine seep areas, wet marshy places and riparian areas. C. californicum prefers shade and often grows with Darlingtonia californica and with Calocedrus decurrens (Incense Cedar). It flowers from June to August. 

Sources: Cribb 1997, Frosch and Cribb 2012, Coleman 1989, and Kartesz 1994.

Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade:

No medicinal uses recorded but the species is collected by garden lovers.

Threats [top]

Major Threat(s):

Cypripedium californicum is under numerous anthropogenic threats including habitat loss and disturbance of its restricted range due to urbanization, clear-cutting, suppression of natural disturbance regimes, logging practices, accidental trampling, climate change and collection. In addition to deforestation, hydrological alterations, human interferences, drainage and mining operations pose major threats to some populations (Coleman 1989, Kartesz 1994).

Conservation Actions [top]

Conservation Actions:

All orchid species are included under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

The following actions are recommended to protect Cypripedium californicum:

- Protection of the habitat, especially the serpentine seep areas from logging and mining activities.

- Fencing the vulnerable sites to protect the species from collection.

- Control the supply of sun light to the forest floor as the species prefers shade.

 - Sympathetic management of isolated populations.

- Raising public awareness.

- Protection of living individuals of the species through legislation and legal protection which ban the species being picked or dug up.

- Ex situ conservation: artificial propagation, re-introduction, seed collections.

- Monitoring and surveillance of the existing populations and sites.

- Estimation of population sizes and study their dynamics. 

Sources: Coleman 1989 and Kartesz 1994.

Citation: Rankou, H. 2014. Cypripedium californicum. The IUCN Red List of Threatened Species 2014: e.T43315511A43327619. . Downloaded on 17 August 2018.
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