(Map may reflect historical as well as recent sightings)
The Siskiyou mariposa lily became
a candidate species in June 2002. An annual review of the species'
status was conducted in Decmeber 2007.
Historical Status and Current Trends
The Siskiyou mariposa lily (Calochortus persistens) is listed
as a sensitive species by the USDA Forest Service in their Region 5, and
listed as a rare species by the state of California (California Department
of Fish and Game 2006). The Oregon Department of Agriculture does
not include Siskiyou mariposa lily on the state of Oregon's threatened
or endangered plant list. However the Oregon Natural Heritage Information
Center ranks Siskiyou mariposa lily as an S1 species, i.e., critically
imperiled statewide (Oregon State University 2006).
Description and Life History
Siskiyou mariposa lily (Family Liliaceae) is an herbaceous
perennial with a single, basal leaf arising from a bulb. The basal
leaf can be up to 20 centimeters (7.9 inches) in length and the flowering
stem approximately 10 centimeters (3.9 inches) high. One to two
large showy, pink to lavender, erect, bell-shaped flowers have a yellow
fringe above the nectary at the base of the petals (Ownbey 1940).
In Oregon, the habitat is similar to the habitat of the California populations. Siskiyou
mariposa lily is found at 1,707 meters (5,600 feet) in McMullin Rock Outcrop
Complex soils, which are also shallow talus soils (B. Tong in litt. 2006). In
Oregon, Siskiyou mariposa lily is found in an open rock outcrop barren
associated with Ponderosa pine, ocean spray, Fremont’s
silk tassel, bitter cherry, Idaho fescue, lace lipfern, and wild
buckwheat species (B.Tong in litt. 2006).
In California, Siskiyou mariposa lily occurs at elevations of 1,310 meters
(4,300 feet) to 1,847 meters (6,060 feet) on ridgeline rock outcrops and
talus, where the soils are shallow, dry, rocky, and acidic (Klamath National
Forest 1987, Klamath-Siskiyou Wildlands Center et al. 2001). These
soils are well drained and dry early in the season after snowmelt. Siskiyou
mariposa lily plants are found in greater numbers on north-facing slopes. The
plants are almost entirely restricted to the rockiest portions of the
ridge tops and ridge shoulders, and do not extend very far down the associated
Siskiyou mariposa lily is a narrow endemic that occurs in
the Klamath-Siskiyou Range, on the California-Oregon border and
in a few locations in southern Oregon. In California, this species
is currently found at ten separate sites in the Klamath National
Forest and privately-owned lands along the Gunsight-Humbug Ridge. Oregon
populations are located near Bald Mountain of Jackson County but
an extirpated population once occurred on Red Mountain
near the Oregon–California
Reasons for Decline
Industrial, commercial, and residential development, road and power-line
construction and maintenance, livestock grazing, agricultural conversion,
weed competition, mowing, and roadside spraying have all contributed to
the decline of this species.
The Fish and Wildlife Service and the Medford District of the Bureau
of Land Management have funded efforts to document the Siskiyou
location, monitor the health of the population and evaluate potential
threats to its continued existence. Additionally,
surveys in suitable habitat in the Bald Mountain area for currently
undocumented populations of the Siskiyou mariposa lily will be accomplished
in 2008 through 2010.
References and Links
Klamath National Forest. 1987. Calochortus persistens habitat
inventory and status investigation. Unpublished report prepared for the
Klamath National Forest, Yreka, California. July 27, 1987. 5
pp. + appendices.
Klamath-Siskiyou Wildlands Center, Oregon Natural Resources Council,
and B. Knapp. 2001. Formal petition to list the Siskiyou mariposa
lily endangered under the Endangered Species Act. Ashland, Oregon. 20
pp. + appendices.
Ownbey, M. 1940. A monograph of the genus Calochortus. Annals
of the Missouri Botanical Garden, vol. 27. no. 4. November 1940.
Tong, B. 2006. Email with attachment from Brad Tong, U.S.
Department of the Interior, Bureau of Land Management, Medford, Oregon,
to Marla Knight, Klamath National Forest. May 31, 2006.
U.S. Fish and Wildlife Service (USFWS). 2002. Endangered
and threatened wildlife and plants; Review of species that are candidates
or proposed for listing as endangered or threatened; Annual notice
of findings on recycled petitions; annual description of progress
on listing actions. FR
67:40657-40679. June 13, 2002.