- Eudicots are a major lineage of flowering plants; see family for general characteristics
- Broomrape Family (Orobanchaceae)
- Annual herb
- Hairy and non-glandular (sticky)
- Alternate (1 leaf at each junction with stem), with blades attached directly to the stem (sessile)
- Linear, usually with deeply-cut lobes
- 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.
- 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)
- 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
- 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
- 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)
- 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|
|Sepal Color||green to pink|
light pink tips
white or yellow tips
|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|
² Beak: 2 upper fused petals
- Found in grasslands
- See iNaturalist for observations of this plant
- Flowers April – May
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.
—–. 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.
—–. 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.
—–. 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.
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.