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Sexton Mountain mariposa lily (Calochortus indecorus)
ENDANGERED (possibly extinct)
Calochortus indecorus flowers and fruit
Calochortus indecorus herbarium specimen
Close-up of the flowers and fruit of the Sexton Mountain mariposa lily (left) and the entire plants, including bulbs (right), from the holotype herbarium specimen of the species, courtesy of the OSU Herbarium.
 

Family
Liliaceae

Plant description
Calochortus indecorus (Sexton Mountain mariposa lily) is a bulbous perennial with a stout stem and a single basal leaf 2-2.5 dm long. The 2-2.5 cm bulb is ovoid, with a thick, dark coat. Flowers are bright lavender, with hairs in only a small area at the base of the petals above the gland. The two to four flowers are arranged in one or two loose umbels. Sepals are broadly lance-shaped, slightly shorter than the petals, and lack distinctive coloring. The 1.5-2 cm seed capsule is nodding at maturity.

Distinguishing characteristics
Calochortus uniflorus (meadow mariposa lily) is similar to C. indecorus, but this more common pink-flowered species produces bulblets at the base of the leaves, and has a shorter stem (2-5 cm high below the inflorescence) than the "rather stout" 8-12 cm stem (below the inflorescence) of the rare species. Several other mariposa lilies found in southwest Oregon are also similar in appearance to C. indecorus, but each has distinct differences. The flowers of Calochortus howellii (Howell’s mariposa lily) are white; those of C. tolmiei (cat’s ear mariposa lily) are also whitish, though often with a purple tinge, and have distinctly hairy petals. Calochortus nudus (naked mariposa lily), a mainly Californian species of wet meadows, is superficially similar to C. indecorus, but has erect capsules at maturity, while the capsules of C. indecorus are distinctly nodding.

When to survey
Plants comprising the one collection of this species, made in late May, are in both flower and fruit, indicating that late May to early June would be an appropriate time to survey for this species.

Habitat
The type collection label states the source locality as "damp s. slopes of Sexton Mt.," while the species description, published six years after the discovery of the new taxon, identifies the collection location as the "foot of the west slope" of the same mountain. In either case, the habitat occupied by the Sexton Mountain mariposa lily is probably the moist, rocky, serpentine slopes and flats that occur on Sexton and the nearby Red Mountains. Attempts to revisit the collection site, or to locate additional populations of this species, have not been successful, and Sexton Mountain mariposa lily is now thought to be extinct.

Range
This plant has been documented only from Sexton Mountain in Josephine County, Oregon, and is now apparently extirpated from this site.

Oregon counties
Josephine

Federal status
None currently; former candidate for federal listing

Threats
Collection, grazing, and farmland and pasture development were likely threats to the species. Road construction associated with Interstate 5 has been speculated to be the cause of the extirpation of C. indecorus from Sexton Mountain.

Did you know?
The word Calochortus is Greek in origin and means "beautiful grass," an apt description of this group of exceptionally beautiful species with grass-like leaves.

References
Meinke, R.J. 1980. Threatened and endangered vascular plants of Oregon: an illustrated guide. U.S. Fish and Wildlife Service. Portland, OR. 352 pp.
 
Peck, M.E. 1954. A new Calochortus from Oregon. Leaflets of Western Botany 7:190-192.
 
Kaye, T.N. 1998. Survey report for Calochortus indecorus Sexton Mountain mariposa lily. Oregon Department of Agriculture, Salem, Oregon.