Calochortus umbellatus
Oakland star-tulip, Oakland Star-Tulip
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Family: Liliaceae · Type: Herb · Native
Conservation status: CNPS 4.2
Calochortus umbellatus (Oakland star-tulip) is a native California herb in the Liliaceae family, recognized by distinctive umbel-like clusters of small spotted flowers.
Oakland star-tulip is a rare (CNPS 4.2) California native perennial found in southern North Coast Ranges and San Francisco Bay Area in open chaparral and woodland, generally on serpentine at elevations of 100 to 700 meters. Flowering from March to May, this plant produces white or pale pink-lilac flowers with purple spots at the base, bell-shaped and 12 to 18 millimeters long with widely wedge-shaped petals. Growing with stems 8 to 25 centimeters tall and generally two-branched, it emerges from a bulb with a single linear cauline leaf. Its basal leaves persist and reach 20 to 40 centimeters long, with a distinctive nectary covered by a ciliate membrane. The fruit is a nodding, winged capsule 10 to 14 millimeters long containing dark brown, net-like seeds.
Identification and appearance
Key characters: 14 sympatric species; distinctive umbel-like clusters of small spotted flowers
Habitat and range
Habitat: Open chaparral or woodland, generally on serpentine
Elevation: 100-700 m
California counties: Alameda, Marin, Contra Costa, Lake, Mendocino, San Mateo, Santa Clara, Stanislaus, Napa
Bloom period
Calochortus umbellatus blooms Mar-May.
Conservation status
CNPS 4.2
How to tell it apart
vs Clarkia: Calochortus has 6 stamens and grass-like leaves; Clarkia has 8 stamens and broad stem leaves.; vs Fritillaria: Calochortus flowers open upward/outward in cups; Fritillaria flowers hang downward like bells.; vs Thismia: Calochortus has green leaves and open flowers; Thismia is leafless with closed tubular flowers.; vs Eschscholzia: Calochortus has 6 petals and parallel-veined leaves; Eschscholzia has 4 petals and divided leaves.; vs Sidalcea: Calochortus has 6 petals and grass-like leaves; Sidalcea has 5 petals and rounded lobed leaves.
Frequently asked questions
Is Calochortus umbellatus native to California?
Yes. Calochortus umbellatus is native to California (recorded as native).
When does Calochortus umbellatus bloom?
Calochortus umbellatus blooms Mar-May.
Where in California does Calochortus umbellatus grow?
Calochortus umbellatus occurs in Alameda, Marin, Contra Costa, Lake, Mendocino, San Mateo, Santa Clara, Stanislaus and other counties, at elevations of 100-700 m.
What plant family does Calochortus umbellatus belong to?
Calochortus umbellatus is in the Liliaceae family, genus Calochortus.
Is Calochortus umbellatus rare or endangered?
Calochortus umbellatus carries California Rare Plant Rank 4.2, state rank S3?.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.