Taxon Report

Calochortus monanthus Ownbey

single-flowered mariposa-lily

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Taxon Summary

Calochortus monanthus, commonly known as single-flowered mariposa-lily, is a perennial bulbiferous herb in the Liliaceae that is found only in California. It occurs within Meadows and seeps, growing at elevations from 745 to 800 meters. Calochortus monanthus is ranked 1A, Plants Presumed Extirpated in California and Either Rare or Extinct Elsewhere.

Classification


Scientific Name:	Calochortus monanthus Ownbey
Common Name:	single-flowered mariposa-lily
Family:	Liliaceae
Element Code:	PMLIL0D0W0
USDA Plants Symbol:	CAMO2
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial bulbiferous herb
Blooming Period: Jun	Jun
Elevation:	745-800 (2445-2625)
General Habitats:	Meadows and seeps
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1A
Global Rank:	GX
State Rank:	SX
State List:	None
Fed List:	None
Other Status:	BLM_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	1
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	1

Location


California Endemic: True
California Counties and Islands: Name (Code)
Siskiyou (SIS)*
Quads: Name (Quad Code)
Hawkinsville (4112275), Montague (4112265)?

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	1	100 %
Grazing	1	100%
Non-native plant impacts	1	100%

Notes



Known only from the type collection (in 1876) along the Shasta River, now mostly converted to agriculture. Rediscovery attempts unsuccessful. See Annals of the Missouri Botanical Garden 27:371-560 (1940) for original description.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 20 November 2025].