Home/Species/ Howell's Mariposa Lily

Calochortus howellii

S. Wats.

Howell's Mariposa Lily

G3Vulnerable Found in 2 roadless areas NatureServe Explorer →

G3VulnerableGlobal Rank

Identity

Unique IDELEMENT_GLOBAL.2.132670

Element CodePMLIL0D0K0

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single state or province

KingdomPlantae

PhylumAnthophyta

ClassMonocotyledoneae

OrderLiliales

FamilyLiliaceae

GenusCalochortus

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Taxonomic Comments

Distinct species, 1 of 11 Oregon species in this genus.

Conservation Status

Review Date2004-02-05

Change Date2004-02-05

Edition Date2002-10-28

Edition AuthorsVrilaks (2002); Roth, E., rev. Kagan/Vrilakas/Maybury (1996)

Range Extent<100-250 square km (less than about 40-100 square miles)

Number of Occurrences21 - 80

Rank Reasons

Although endemic to southwestern Oregon and restricted to serpentine substrates, which are mined for gold, chromium, and nickel, this species can be locally abundant with some large population sizes. The number of known occurrences is about 50; total plants numbers at least 65,000.

Range Extent Comments

Known only from southwestern Oregon, Douglas and Josephine Counties, Oregon.

Occurrences Comments

There are about 50 known occurrences.

Threat Impact Comments

Threatened by urban growth, livestock grazing, mining of the mineral rich serpentine substrate, horticultural collecting, fire suppression methods.

Ecology & Habitat

Description

This lily-like plant has an erect, slender bloom stalk that grows up to 18 inches tall (4.5 dm) with 1 or 2 wide upright, bell-shaped, pure white flowers (or white with a greenish tinge) with brownish bases which are less than an inch long (2.5 cm). Dense white to brownish to greenish hairs cover the dark base of the petals. Sepals are white and narrow. The capsule is elliptic, erect, less than 3/4 of an inch long. A single basal leaf sometimes longer that the flower stalk and about 1/3 inch wide (10mm) is densely hairy on the upper surface in the middle.

Habitat

Serpentine outcrops at lower or middle elevations. Always on dry slopes with buckbrush (Ceanothus cuneatus), sticky manzanita (Arctostaphylos viscida), or, rarely, Brewer oak (Quercus breweri) or sparse Jeffrey pine (Pinus jeffreyi).

Terrestrial Habitats

Forest/WoodlandWoodland - HardwoodWoodland - ConiferWoodland - MixedShrubland/chaparral

Other Nations (1)

United StatesN3

Province	Rank	Native
Oregon	S2	Yes

Plant Characteristics

Economic Value (Genus)No

Roadless Areas (2)

Oregon (2)

Area	Forest	Acres
North Kalmiopsis	Siskiyou National Forests	91,560
South Kalmiopsis	Siskiyou National Forests	104,477

References (5)

Flora of North America Editorial Committee (FNA). 2002a. Flora of North America north of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.
Fredricks, N.A. 1986. Calochortus howellii: Ecology of a rare serpentine endemic and comparison with the new species, C. umpquaensis (Liliaceae). M.S. thesis, Oregon State University, Corvallis.
Fredricks, N.A. 1989. Morphological comparison of Calochortus howellii and a new species from southwestern Oregon, C. umpquaensis (Liliaceae). Systematic Botany 14(1):7-15.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Meinke, R.J. 1982. Threatened and Endangered Vascular Plants of Oregon: An Illustrated Guide. U.S. Fish and Wildlife Service, Region 1, Portland, Oregon. 326 pp.