Valley Tassels :

Narrow-leaved Owl’s-clover
Castilleja attenuata
NATIVE

Description (Jepson, PlantID.net)

Eudicotyledon
- Eudicots are a major lineage of flowering plants; see family for general characteristics
Broomrape Family (Orobanchaceae)
Annual herb
- Hairy and non-glandular (sticky)
Leaves
- Alternate (1 leaf at each junction with stem), with blades attached directly to the stem (sessile)
- Linear, usually with deeply-cut lobes
Flowers
- Inflorescence (flower arrangement) is a narrow spike (single stem bearing stalkless flowers)
- Bracts (modified leaves) at base of inflorescence and sepals (usually green, outer flower parts) are lobed and tipped white or yellow
- Bilaterally-symmetrical flowers are white to pale yellow with purple and yellow accents
  - Tube-shaped, partially covered by bracts and sepals
  - 5 fused petals in two sets
    - 2-lobed upper lip creates a straight beak (a slender projection), with fine short hairs (puberulent)
    - 3-lobed lower lip forms a slender pouch with purple spots
  - Stigma (pollen-receiving part of the pistil/female structure) not projecting (exserted)
- Ovary superior (above the attachment of other flower parts)
Height to 20 in.

Distribution

Native to California
- Grows in grasslands, foothill woodlands, chaparral, and mixed evergreen forests
- See Calflora for statewide observations of this plant
Outside California, grows from British Columbia, Canada to northern Baja California, Mexico
Grows at elevations to 5,250 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)
- Owl’s-clovers play a major role in efforts to re-establish the Bay Checkerspot Butterfly at Edgewood
Native people
- Harvested the seeds of owl’s-clovers (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
attenuata (a-ten-yoo-AY-ta) – from the Latin attenuāre, “to make thin, reduce,” referring to the slender growth habit

Notes

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)

ID Tips

May be confused with 3 other grassland Castilleja species at Edgewood: dense-flowered owl’s-clover (C. densiflora ssp. densiflora), purple owl’s-clover (C. exserta ssp. exserta), and yellow cream sacs (C. rubicundula ssp. lithospermoides)
- Valley tassels is the only one of these with mainly white flowers

	Dense-flowered Owl’s-clover	Purple Owl’s-clover	Valley Tassels	Yellow Cream Sacs
Hairiness	slightly hairy	densely hairy (cobwebby)	slightly hairy	hairy
Inflorescence	dense spike	dense spike	narrow spike	bulging spike
Flower
Sepal Color	green to pink … light pink tips	magenta … pink tips	green … white or yellow tips	green
Petal Color	mostly 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
Pouch¹	inflated	inflated	slightly inflated	greatly inflated
Beak²	straight … not hairy	hooked … densely hairy	straight … not hairy	straight … 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)
© JMason and © LMiller and © Regents of the University of California

At Edgewood

Found in grasslands
- See iNaturalist for observations of this plant
Flowers April – May

Specific References

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

Heckard, L.R. 1962. Root parasitism in Castilleja. Abstract. Botanical Gazette 124(1).

Mason, J. 2004. Scrophulariaceae — Figwort family characteristics [Illustration of owl’s clover beak, adapted]. 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 [Illustration, adapted]. 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 densiflora ssp. densiflora [Illustration, adapted]. 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 exserta ssp. exserta [Illustration, adapted]. 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 rubicundula ssp. lithospermoides [Illustration, adapted]. 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.

Press, M.C. 1998. Dracula or Robin Hood? A functional role for root hemiparasites in nutrient poor ecosystems. Oikos 82: 609-611. JSTOR.

Regents of the University of California. Castilleja exserta subsp. exserta [Illustration of beak, adapted]. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.

Regents of the University of California. Castilleja rubicundula subsp. lithospermoides [Illustration of beak, adapted]. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.

Shapiro, A.M., and T.D. Manolis. 2007. Field Guide to Butterflies of the San Francisco Bay and Sacramento Valley Regions. University of California Press, Berkeley and Los Angeles, California.

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.

Charters, M.L. 2017. Southern California Wildflowers: Guide to the Pronunciation of Specific, Generic and Family Names.

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.

Harris, J.G., and M.W. Harris. 2013. Plant Identification Terminology: An Illustrated Glossary. Spring Lake Publishing, Spring Lake, Utah.

Keator, G. 2009. California Plant Families. University of California Press, Berkeley and Los Angeles, California.

Native American Ethnobotany DB.

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