Taxon Report

Calochortus umbellatus A.W. Wood

Oakland star-tulip

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Taxon Summary

Calochortus umbellatus, commonly known as Oakland star-tulip, is a perennial bulbiferous herb in the Liliaceae that is found only in California. It occurs within Broadleafed upland forest, Chaparral, Cismontane woodland, Lower montane coniferous forest, and Valley and foothill grassland, growing at elevations from 100 to 700 meters. Calochortus umbellatus is ranked 4.2, Plants of Limited Distribution, A Watch List; Moderately threatened in California.

Classification


Scientific Name:	Calochortus umbellatus A.W. Wood
Common Name:	Oakland star-tulip
Family:	Liliaceae
Element Code:	PMLIL0D1E0
USDA Plants Symbol:	CAUM
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial bulbiferous herb
Blooming Period: Mar-May	Mar-May
Elevation:	100-700 (330-2295)
General Habitats:	Broadleafed upland forest, Chaparral, Cismontane woodland, Lower montane coniferous forest, Valley and foothill grassland
Microhabitat:	Serpentine (often)
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	4.2
Global Rank:	G3?
State Rank:	S3?
State List:	None
Fed List:	None
Other Status:	SB_UCBG
CRPR Changes:

Occurrence Data from the CNDDB


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

Location


California Endemic: True
California Counties and Islands: Name (Code)
Alameda (ALA), Contra Costa (CCA), Marin (MRN), San Mateo (SMT), Santa Clara (SCL)
Quads: Name (Quad Code)
Bolinas (3712286), Briones Valley (3712282), Diablo (3712178), Hayward (3712261), Las Trampas Ridge (3712271), Lick Observatory (3712136), Mt. Day (3712146), Novato (3812215), Oakland East (3712272), Point Reyes NE (3812227), Richmond (3712283), San Geronimo (3812216), San Mateo (3712253), San Quentin (3712284), San Rafael (3712285), Walnut Creek (3712281), Woodside (3712243)

Threat List Data from the CNDDB


Threat List Total:	0
EOs with Threat Listed:	Total EOs	% of EOs
	0	0 %

Notes



Possibly threatened by recreational activities. See Proceedings of the Academy of Natural Sciences of Philadelphia 20(6):168 (1868) for original description, and Proceedings of the California Academy of Sciences III 2:123-124 (1901) for taxonomic treatment.
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 30 January 2025].