Chaparro – Castela emoryi

Chaparro - Castela emoryi, photos by Steven Foster

Overall At-Risk Score: 39

Latin name:

Castela emoryi

Common Name:

Chaparro Amargosa, Crucifixion Thorn, Emory’s Crucifixion Thorn


Simaroubaceae (Quassia family)


Perennial, long-lived shrub or tree


Several species of bugs are responsible for the pollination of C. emoryi, primarily bees and wasps. Not much is known about the seed germination of this species, with some suggesting that it needs to be passed through the gut of an animal to germinate. C. emoryi has been observed holding onto its seed clusters for upwards of 7 years, and seedlings are not commonly found.

Geographic Region:

Chaparro can be found in Southwestern Arizona and Southern California. It is also found in the Mexican state of Sonora.


C. emoryi grows in small patches scattered throughout dry lakes and rocky desert plains at around 2130 ft (650 m).

Vulnerability of Habitat/Changes of Habitat Quality and Availability:

Ironically, some of humanity’s attempts to help the planet may actually be hurting this species. The large flat regions that are ideal for solar farms are also the only places C. emoryi is capable of growing, and underground water sources are commonly piped out to wash off dust and sand that rapidly accumulates on the solar panels in the desert.

Another big concern is the presence of dune buggies and motorcyclists. Despite being closed for off-road vehicles back in 2002, the limited habitable regions are still frequented by drivers, who can crush the already-rare seedlings.

Status of Endangered/Threatened (by state):

Castela emoryi is listed in Arizona as “Salvage restricted,” which is reserved for native plants that are commonly disturbed or otherwise vandalized.

Castela emoryi has not yet been evaluated by the IUCN Red List.

Part of Plant Used/Active Medicinal Compounds:

Historically, the buds of this plant were applied by the Yavapai as a paste in an attempt to stop pimples. It is also seen use as a natural pesticide against termites due to the presence of the toxicant glaucarubolone glucoside.

Wild Harvesting Impact On Other Species and Lookalikes:

Several species of bees and wasps are known to visit the flowers of the crucifixion thorn, and its nectar is collected by ants. It is theorized that C. emoryi serves as an important source of resources since it is one of the few plants in the area that is in bloom in the mid-summer heat.

Recommendations For Industrial and Home Use:

We suggest looking elsewhere for your natural pesticide needs and not disturbing the area in which C. emoryi lives. Please talk to your doctor before attempting to take Castela emoryi or any other medicinal plant.


  • Bell, Duncan S., and Herskovits, Tasya, (2013), “A Newly Discovered Large and Significant Population of Castela emoryi (Emory’s Crucifixion Thorn, Simaroubaceae) in California,” Aliso: A Journal of Systematic and Evolutionary Botany: Vol. 31: Iss. 1, Article 7. Available at:
  • Gifford, E. W., 1936, Northeastern and Western Yavapai, University of California Publications in American Archaeology and Ethnology 34:247-345, page 261
  • Gutiérrez, C., Gonzalez-Coloma, A., & Hoffmann, J. J. (1999). Antifeedant properties of natural products from Parthenium argentatum, P. argentatum×P. tomentosum (Asteraceae) and Castela emoryi (Simaroubeaceae) against Reticulitermes flavipes. Industrial Crops and Products, 10(1), 35–40. doi:10.1016/s0926-6690(99)00003-5.
  • Robert E. Preston & Elizabeth McClintock 2012, Castela emoryi, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on September 01, 2019.
  • USDA, (n.d.), Plants Profile for Castela emoryi (crucifiction thorn), Retrieved September 1, 2019, from

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