Castilleja exserta
Conservation status
Apparently Secure  ( NatureServe) [1]
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Lamiales
Family:	Orobanchaceae
Genus:	Castilleja
Species:	C. exserta
Binomial name
Castilleja exserta (Heller) Chuang & Heckard

Castilleja exserta (formerly Orthocarpus purpurascens) is a species of plant in the genus Castilleja which includes the Indian paintbrushes. Its common names include purple owl's clover, escobita, and exserted Indian paintbrush. ^[2]

This species is native to the Southwestern United States in various habitats of California, Arizona, and New Mexico; and to Northwestern Mexico. ^[3] It is an introduced species in Hawaii.

Description

Castilleja exserta is an annual herb about 100–450 millimetres (4–18 in) tall with a hairy stem covered in thready leaves. Like other related Castilleja plants, this species is a hemiparasite, deriving some of its nutrients directly from the roots of other plants by infiltrating them with haustoria. As a result, its own leaves are small and reduced.

Although this species is variable in appearance and easily hybridizes with other Castilleja species, it generally bears a brightly colored inflorescence of shaggy pink-purple or lavender flowers. The thin, erect bracts are usually tipped with the same color, giving the inflorescence the appearance of a paintbrush. ^[4]

Varieties

Varieties include:

• Castilleja exserta var. exserta — pale purple owlclover. ^{[5] [6]}
• Castilleja exserta var. latifolia — wideleaf Indian paintbrush; endemic to coastal California. ^{[6] [7] [8]}
• Castilleja exserta var. venusta — endemic to California: Mojave Desert, southern San Joaquin Valley. ^{[6] [9] [10] [11]}

Bay checkerspot butterfly host

This is a crucial host plant for the Bay checkerspot butterfly (Euphydryas editha bayensis), which is a threatened species that is endemic to the San Francisco Bay region in California.

The seeds were harvested by indigenous peoples of California for food. ^[12]

• 
• 
  2015
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  Antelope Valley Purple owl's clover

References

External links

• Media related to Castilleja exserta at Wikimedia Commons
• Closeup photos — at Henry Coe State Park, S.F. Bay Area.
• Castilleja exserta — U.C. Photo gallery