Yellow Mariposa Lily

Calochortus luteus
NATIVE – CA ENDEMIC

Description (Jepson, PlantID.net)

• Monocotyledon
  • Monocots are a major lineage of flowering plants; see family for general characteristics
• Lily Family (Liliaceae)
• Upright, herbaceous perennial
  • Grows from a bulb (short underground stem with fleshy leaves, e.g. onion)
• Leaves
  • Narrow basal leaves, with alternating linear leaves along the stem
  • Wither before flowering
• Flowers
  • Inflorescence (flower arrangement) of 1-7 upright, yellow, cup-shaped flowers
  • 3 wedge-shaped yellow petals, lower halves with radiating red-brown streaks
  • Conspicuous nectary glands with dense orange-red hairs
  • Narrow sepals (usually green, outer flower parts) curl back and often show between petal gaps
  • Ovary superior (above the attachment of other flower parts)
• Fruit is an erect capsule (a dry, multi-chambered fruit that splits open at maturity) with many seeds
• Height to 24 in.

Distribution

• Native and endemic (limited) to California
  • Grows in grasslands
  • See Calflora for statewide observations of this plant
• Grows at elevations to 2,300 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

• Wildlife
  • Pollen and nectar source for bees, beetles, and many other insects, including orange tortrix moth (Argyrotaenia franciscana), small heliothodes moth (Heliothodes diminutiva), and gray buckeye butterfly (Junonia grisea)
  • Larval food source for butterflies (Calscape 2018)
• Native people
  • Ate the bulbs boiled, steamed, roasted, or baked in earthen ovens (Anderson 2005)
  • In early spring, bulbs were peeled and eaten raw
  • Some tribes pounded dried bulbs into a flour and ate as a mush
  • See Lily family for more details about how Native people actively managed edible geophytes

Name Derivation

• Calochortus (kal-oh-KOR-tus) – from the Greek kallos, “beautiful,” and chortus, “grass,” referring to the leaves
• luteus (LOO-tee-us) – Latin for “yellow”
• Mariposa – Spanish for “butterfly,” for the intricate petal patterns reminiscent of butterfly wings

Notes

• Geophytes (e.g. plants growing from bulbs, corms, rhizomes, or enlarged taproots) are well adapted to survive fire, our Mediterranean climate’s long, dry summers, and extended droughts
  • Above-ground growth dies back after flowering, while underground the plant survives with stored water and nutrients
• The genus Calochortus is known for large, showy flowers above “beautiful grass” leaves
  • Range includes western North America, Mexico, and south to Guatemala
  • Greatest concentration of species is in California (Pacific 2025; Wood 2006)
    • The San Francisco Bay Area has 18 species – a center of Calochortus diversity! (Naumovich 2015)
  • Species are grouped into 3 flower forms
    • Globe lilies or “fairy lanterns” (nodding, globe-shaped flowers)
    • Mariposa lilies (open, upright flowers and wedge-shaped petals)
    • Cat’s ears and star tulips (open, upright flowers, pointed petals)
  • Edgewood has one globe lily (white globe lily) and two mariposa lilies (yellow mariposa lily and clay mariposa lily)
    • Cat’s ears can be found nearby in the Phleger Estate and Huddart County Park

ID Tips

• Differs from clay mariposa lily (C. argillosus)
  • Yellow mariposa lily has yellow petals with red-brown markings
  • Clay mariposa lily has white petals with red, pink, and yellow markings

At Edgewood

• Found in serpentine and non-serpentine grasslands
  • See iNaturalist for observations of this plant
• Flowers April-June

Specific References

Anderson, M.K. 2005. Tending the Wild. University of California, Berkeley.

Gerritsen, M.E., and R. Parsons. 2007. Calochortus: Mariposa Lilies and Their Relatives. Timber Press, Portland, Oregon.

Naumovich, L. 2015, May 1. Calochortus lilies catch the eye. Bay Nature.

Pacific Bulb Society. 2025. Calochortus species four. Pacific Bulb Society Wiki.

Wood, M. 2006, Jun. 6. Yellow mariposa lily (Calochortus luteus). California Native Plant Society Yerba Buena Chapter.

General References

Calflora Database. 2014. Berkeley, California.

Calscape. 2018. California Native Plant Society.

Charters, M.L. 2015. California Plant Names: Latin and Greek Meanings and Derivations.

Corelli, T. 2004. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California.

Dave’s Garden.

Elpel, T.J. 2013. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, Pony, Montana.

Flora of North America. efloras.org.

Native American Ethnobotany DB.

Regents of the University of California. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.