Calochortus tiburonensis
Tiburon mariposa lily
(c) Adam J. Searcy, some rights reserved (CC BY), uploaded by Adam J. Searcy · licence
Family: Liliaceae · Type: Herb · Native
Conservation status: CNPS 1B.1 · Threatened
Calochortus tiburonensis (Tiburon mariposa lily) is a native California herb in the Liliaceae family, recognized by distinctive yellow-green flowers on serpentine.
Tiburon mariposa lily is a rare (CNPS 1B.1) California native perennial found in northern Central Coast bioregion at Ring Mountain in Marin County within serpentine grassland at elevations of 50 to 150 meters. Flowering from May to June, this plant produces light yellow-green flowers flecked with purple-brown, with delicate oblanceolate petals that are ciliate and hairy, creating an elegant bell-shaped perianth. Growing 10 to 60 centimeters tall with generally branched stems, it emerges with a long basal leaf up to 70 centimeters and several reduced cauline leaves ascending the stem. Its distinctive petals feature a depressed nectary bordered by a ciliate membrane and short hair rows, giving the flower a complex and intricate appearance. The fruit is erect and angled, measuring 20 to 30 millimeters long with an acute tip, containing irregular dark brown to black seeds.
Identification and appearance
Key characters: 11 sympatric species; distinctive yellow-green flowers on serpentine
Habitat and range
Habitat: Serpentine grassland
Elevation: 50-150 m
California counties: Marin
Bloom period
Calochortus tiburonensis blooms May-Jun.
Conservation status
CNPS 1B.1 · Threatened
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 tiburonensis native to California?
Yes. Calochortus tiburonensis is native to California (recorded as native).
When does Calochortus tiburonensis bloom?
Calochortus tiburonensis blooms May-Jun.
Where in California does Calochortus tiburonensis grow?
Calochortus tiburonensis occurs in Marin, at elevations of 50-150 m.
What plant family does Calochortus tiburonensis belong to?
Calochortus tiburonensis is in the Liliaceae family, genus Calochortus.
Is Calochortus tiburonensis rare or endangered?
Calochortus tiburonensis carries California Rare Plant Rank 1B.1, state rank S1.
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.