Castilleja exserta explained

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.^[1]

This species is native to the Southwestern United States in various habitats of California, Arizona, and New Mexico; and to Northwestern Mexico.^[2] It is an introduced species in Hawaii.

Description

Castilleja exserta is an annual herb about 100mm450mm 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.^[3]

Varieties

Varieties include:

• Castilleja exserta var. exserta — pale purple owlclover.^{[4] [5]}
• Castilleja exserta var. latifolia — wideleaf Indian paintbrush; endemic to coastal California.^{[6] [7]}
• Castilleja exserta var. venusta — endemic to California: Mojave Desert, southern San Joaquin Valley.^{[8] [9] [10]}

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.^[11]

External links

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

Notes and References

1. http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Castilleja+exserta CalFlora database: Castilleja exserta
2. Web site: Castilleja exserta . Sullivan . Steven. K. . 2018 . Wildflower Search . 2018-07-06 .
3. Web site: Castilleja exserta . 2018 . in Jepson Flora Project (eds.) Jepson eFlora . Jepson Herbarium; University of California, Berkeley . 2018-07-06.
4. http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Castilleja+exserta+ssp.+exserta&one=T CalFlora: Castilleja exserta ssp. exserta
5. Web site: Castilleja exserta (A.Heller) T.I.Chuang & Heckard Plants of the World Online Kew Science. 2021-07-19. Plants of the World Online. en.
6. http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Castilleja+exserta+ssp.+latifolia&one=T CalFlora: Castilleja exserta ssp. latifolia
7. Web site: Castilleja exserta var. latifolia (S.Watson) J.M.Egger Plants of the World Online Kew Science. 2021-07-19. Plants of the World Online. en.
8. http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Castilleja+exserta+ssp.+venusta&one=T CalFlora: Castilleja exserta ssp. venusta
9. http://plants.usda.gov/java/nameSearch?mode=symbol&keywordquery=CAEXV USDA: C. e. ssp. venusta
10. Web site: Castilleja exserta var. venusta (A.Heller) J.M.Egger Plants of the World Online Kew Science. 2021-07-19. Plants of the World Online. en.
11. http://www.wildflower.org/plants/result.php?id_plant=CAEX14 Lady Bird Johnson Wildflower Center Native Plant Information Network (NPIN) — Castilleja exserta (Purple owl's clover)