Yellow Cream Sacs

Yellow Cream Sacs © DSchiel

Castilleja rubicundula ssp. lithospermoides

Description (Jepson,

  • Eudicotyledon
    • Eudicots are a major lineage of flowering plants; see family for general characteristics
  • Broomrape Family (Orobanchaceae)
  • Annual herb, semi-parasitic
    • Hairy and glandular (sticky)
  • Leaves
    • Alternate (1 leaf at each junction with stem), with blades attached directly to the stem (sessile)
    • Lance-shaped
  • Flowers
    • Inflorescence (flower arrangement) is a dense spike (single stem bearing stalkless flowers)
      • Bracts (modified leaves) at base are green and lobed
    • Bilaterally-symmetrical flowers are yellow
      • Tube-shaped, partially covered by bracts and sepals (usually green, outer flower parts)
      • 5 petals in two sets
        • 2-lobed upper lip creates a straight beak (a slender projection)
        • Lower lip forms 3 inflated pouches
      • Stigma (pollen-receiving part of the pistil/female structure) exserted atop the beak
    • Ovary superior (above the attachment of other flower parts)
  • Fruit is a capsule
  • Height to 28 in.


  • Native to California
    • Grows in grasslands
    • 55-64% of plants occur on ultramafic soils, e.g. serpentine; see ultramafic affinity rankings (Calflora per Safford and Miller 2020)
    • See Serpentine Grassland for more about Edgewood’s serpentine soil and the unique communities it supports
    • See Calflora for statewide observations of this plant
  • Outside California, grows in southwestern Oregon
  • Grows at elevations to 2,950 ft.

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

  • Wildlife
    • Larval food source (host) for several butterfly species, e.g. common buckeye (Junonia coenia), Leanira checkerspot (Chlosyne leanira), variable checkerspot (Euphydryas chalcedona), and the endangered Bay checkerspot (E. editha bayensis)
    • Yellow cream sacs play a role, along with other related owl’s-clovers (see chart), in efforts to re-establish the Bay Checkerspot Butterfly at Edgewood
  • Native people
    • Harvested the seeds of Castilleja species, which were an important food source (Anderson 2005)
      • Flowers were used in ceremonial wreaths

Name Derivation

  • Castilleja (kas-til-AY-ha) – named for Domingo Castillejo Muñoz (1744-1793), a Spanish surgeon and professor of botany
  • rubicundula (roo-bee-KUND-yoo-la) – from the Latin rubicunda, “reddish”
  • lithospermoides (lith-oh-sper-MOI-dees) – from the Greek lithos, “stone,” and sperma, “seed”


  • Partial root parasite (hemiparasitic)
    • Capable of photosynthesis, but obtains nutrients and water from a variety of other plants (Heckard 1962)
    • Specialized root structures called haustoria (singular, haustorium) penetrate the host plant’s roots
  • Plants in the genus Castilleja are known to hybridize
  • Formerly in the Figwort family (Scrophulariaceae)
  • Edgewood’s yellow cream sacs is classified as a subspecies
    • Subspecies rank is used to recognize geographic distinctiveness, whereas variety rank is appropriate for variants seen throughout the geographic range of the species; in practice, these two ranks are not distinct

ID Tips

Dense-flowered Owl’s-cloverPurple Owl’s-cloverValley TasselsYellow Cream Sacs
Hairinessslightly hairydensely hairy (cobwebby)slightly hairyhairy
Inflorescencedense spikedense spikenarrow spikebulging spike
   Sepal Colorgreen to pink

light pink tips

pink tips

white or yellow tips

   Petal Colormostly white with pink

yellow and purple accents
white and magenta or pink

yellow and purple accents
white to pale yellow

yellow and purple accents

bright yellow to cream
   Pouch¹inflatedinflatedslightly inflatedgreatly inflated

not hairy

densely hairy

not hairy

not hairy
¹ Pouch: 3 lower fused petals
² Beak: 2 upper fused petals

Dense-flowered Owl’s-clover (L), Purple Owl’s-clover (LM), Valley Tassels (RM), Yellow Cream Sacs (R)
© DSchiel (L, LM, R), TCorelli (RM)

Dense-flowered Owl’s-clover (L), Purple Owl’s-clover (LM), Valley Tassels (RM), Yellow Cream Sacs (R)
© See Specific References

At Edgewood

  • Found in serpentine and non-serpentine grasslands
    • See iNaturalist for observations of Castilleja rubicundula
  • Flowers April – June

See General References

Specific References

Alexander, E.B. 2010, Oct. & 2011, Jan. Serpentine soils and why they limit plant survival and growth. Fremontia 38/39: 28-31.

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

Heckard, L.R. 1962. Root parasitism in Castilleja. Abstract. Botanical Gazette 124(1). The University of Chicago Press Journals.

Mason, J. 2004. Owl’s clover beak [Illustration, adapted]. In T. Corelli, Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.

Miller, L.B. 2004. Castilleja attenuata, Castilleja densiflora ssp. densiflora, Castilleja exserta ssp. exserta, and Castilleja rubicundula ssp. lithospermoides [Illustrations]. In T. Corelli, Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California. (c) CC BY NC 3.0.

Mitchell, M. 2017. Orobanchaceae: Broomrape family — Castilleja (Paintbrush & owl’s-clover). Monterey County Wildflowers, Trees, and Ferns – A Photographic Guide.

Regents of the University of California. Castilleja exserta subsp. exserta. [illustration of beak, adapted] in Jepson Flora Project (Eds.). Jepson eFlora.

—–. Castilleja rubicundula subsp. lithospermoides. [illustration of beak, adapted] in Jepson Flora Project (Eds.). Jepson eFlora.

Safford, H.D. 2010, Oct. & 2011, Jan. Serpentine endemism of the California flora. Fremontia 38/39: 32-39.

Safford, H.D. and J.E.D. Miller. 2020. An updated database of serpentine endemism in the California flora. Madroño 67: 85-104. BioOne Complete.