Ruby Chalice Clarkia

Ruby Chalice Clarkia © DSchiel

Clarkia rubicunda

Description (Jepson,

  • Eudicotyledon
    • Eudicots are a major lineage of flowering plants; see family for general characteristics
  • Evening Primrose Family (Onagraceae)
  • Annual herb
    • Upright, with green to reddish stems
  • Leaves are narrow, lance-shaped to elliptic
  • Flowers
    • Inflorescence (flower arrangement) from the leaf axils
      • Apparent flower stalk is a long floral tube (hypanthium)
    • Flower parts in fours
      • 4 rosey-pink to lavender petals in a cup shape
        • Usually with a red ring at the base
      • 4 fused sepals (usually green, outer flower parts), generally bent back (reflexed)
      • 8 stamens (male flower parts), usually with white pollen
      • Stigma (pollen-receiving part of the pistil/female structure) extends beyond (exserted) the anthers (pollen-producing part of the stamen/male structure)
    • Ovary inferior (below the attachment of other flower parts)
  • Fruit is an elongated 4-ribbed capsule (a dry, multi-chambered fruit that splits open at maturity)
  • Height to 20 in.


  • Native and endemic (limited to California)
    • Grows in grasslands, openings in woodlands, and chaparral near the coast
    • See Calflora for statewide observations of this plant
  • Grows at elevations to 1,600 ft.

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

  • Wildlife
    • Insects are the primary pollinators, but most species of Clarkia are capable of self-fertilization
  • Native people
    • Seeds ground to make pinole
      • Pinole is a general term for various flours made from the ground, toasted seeds of wildflowers and grasses, eaten dry or moistened and shaped into balls or cakes (Anderson 2005)
      • “Pinole” is a Hispanic version of an Aztec word
    • Decoction of leaves used as a wash for sore eyes
    • Fields were burned to stimulate the growth of clarkias and other seed-bearing plants (Anderson 2005)
William Clark © CPeale

Name Derivation

  • Clarkia (KLAR-kee-a) – named for William Clark (1770-1838) who, along with Captain Meriwether Lewis, led the first transcontinental expedition (1804-1806) at the request of President Thomas Jefferson
  • rubicunda (rub-ee-KUN-duh) – from Latin rubicundus, “ruddy” or “red,” for the petal color
  • Ruby chalice – from the chalice (cup) flower shape with its wine-like spot at base
  • Alternative common name, farewell-to-spring, is shared by a number Clarkia species, most commonly by Clarkia amoena, which is not found at Edgewood
    • Farewell-to-spring – in reference to the late-blooming habit of this species, which begins blooming in late spring and can continue through the summer


  • Flowers open in the morning and close at end of day
    • This process is an example of nyctinasty, which refers to diurnal and nocturnal changes (single or repetitive) exhibited by the leaves and flowers of some plants (van Doorn 2003)
  • Flowers can self-pollinate (Pollack 2023)
  • Pollen has cobweb-like (viscin) threads
    • Bees in general have specialized electrostatic hairs called scopa (plural, scopae) that store pollen while foraging (Kerstiens 2019)
    • Many bees who visit plants in the Evening Primrose family have evolved modified hairs to handle the sticky pollen characteristic of this family (Portman 2017)
  • Most Clarkia species are strongly protandrous (Raven 1979)
    • Stamens (male flower parts) develop before the pistil (female flower part)
    • The sequential maturation of pistil and stamens is called dichogamy (from the Greek for “divided marriage”)
      • Protogyny describes a pistil maturing before stamens (from the Greek for “female first”)
      • Protandry describes stamens maturing before the pistil (from the Greek for “male first”)
    • Once believed to promote cross-pollination by preventing self-fertilization, dichogamy is now understood to more generally increase the efficiency of sexual functions by preventing mechanical interference (Barrett 2002)
      • Pistil does not interfere with pollen export from the stamens
      • Stamens do not impede contact of pollinator with the stigma (pollen-receiving structure of the female flower)
      • Stigma is not clogged with the plant’s own pollen
  • California has over 70 species and subspecies of plants in the genus Clarkia, named after William Clark, with 20 species found in the greater San Francisco Bay area (Santa Clara County Parks 2020)
    • Some organizations, i.e. San Bruno Mountain Watch’s Mission Blue Nursery and the Golden Gate National Parks Conservancy Nurseries, have renamed the genus Yorkia, to honor York, an enslaved Black member of the expedition (Kilat 2023)

ID Tips

  • May be confused with one other Clarkia species commonly found at Edgewood, four-spot clarkia (C. purpurea ssp. quadrivulnera)
Four-spot ClarkiaRuby Chalice Clarkia

dark spots at tip and base
darker pink to magenta

often with dark ring at base
Stigma¹does not extend beyond anthers²extends beyond anthers²
Sepals³fused in pairs (or come free)fused in fours
¹Stigma: pollen-receiving part of pistil/female structure
²Anther: pollen-producing part of the stamen/male structure
³Sepals: usually green, outer flower parts
(mature stamens on upper left; mature pistil on lower right)
© KKorbholz

At Edgewood

  • Found in serpentine grasslands
  • Flowers April – August

See General References

Specific References

Anderson, M.K. 2005. Tending the Wild. University of California, Berkeley. Pp. 138,184, 264.

Barrett, S. 2002. Sexual interference of the floral kind. Heredity 88: 154–159.

Flowers of Marin. 2013, Jun. 18. Plant of the day – reddened Clarkia.

Kalit, B. 2023. Five tips for decolonizing language. Golden Gate National Parks Conservancy.

Kerstiens, H. 2019, Apr. 3. Charged electrostatic hairs collect pollen granules. Ask Nature. Biomimicry Institute.

Mitchell, M. 2017. Onagraceae: Evening-primrose family — Clarkia. Monterey County Wildflowers, Trees, and Ferns – A Photographic Guide.

Peale, C.W. 1807. William Clark [Illustration, adapted]. Lewis & Clark National Historic Trail. United States National Park Service. Public Domain.

Pollack, A.S. 2023, May 17. These fabulous flowers are spring’s final encoreBay Nature.

Portman, Z. 2017, Jul. 6. The stickiness of Onagraceae pollen. The Science of Species: Understanding and Identifying the Bees of North America.

Raven, P.H. 1979. A survey of reproductive biology in Onagraceae. New Zealand Journal of Botany 17: 575-593. Taylor & Francis.

Santa Clara County Parks. 2020. Plants of Limited Distribution in California. Santa Clara County, California.

van Doorn, W.G. and U. van Meeteren. 2003, Aug. 1. Flower opening and closure: A review. Journal of Experimental Botany 54: 1801–1812. Oxford Academic.