©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
December 2004

     The genus Castela was reviewed by Cronquist (1944, J. Arn. Arb. 25:122–128; Brittonia 5: 128–147, & 1945, Brittonia 5: 469–470) and more recently by Moran and Felger (1968, San Diego Soc. Nat. Hist. Trans. 15: 31–40).  Cronquist (1944) distinguished Castela from other Simaroubaceae genera by the druparium fruit of 4 distinct, 1-seeded monocarps that are united only by their styles in flower, and by having twice as many stamens as petals.  He initially recognized 12 species and one variety in the genus (Cronquist 1944), occurring from southern Texas to West Indies, Mexico, northern South America, and Galápagos Islands, but subsequently reduced the Galapagos Island species to a subspecies of C. erecta (Cronquist 1945). 

     The closely related genus, Holacantha, differs by having more petals, 6–8, and more stamens 12–16, in contrast to the Castela flower with 4-5 petals and 8–10 stamens.  Two relatively rare species were known, H. emoryi from scattered locations in southern California, Arizona, and Baja California, Norte (BCN) and H. stewartii from southern Texas to Coahuila and Zacateca, Mexico.

     However, Moran and Felger (1968), in describing Castela polyandra as a new species, found that this species has features of Holacantha, while also not clearly belonging to Castela.  Consequently, they combined Holacantha with Castela, but recognized three sections, Castela, Holacantha, and the new monotypic Eremacantha.  It is interesting to note that C. polyandra is chemically distinct from other species in having polyandol.  However, C. polyandra is very much like Holacantha in its rigid, spiny, leafless, branches, in having 8–12 stamens, and in lacking spur shoots; it differs primarily in the fewer petals (mostly 4-merous) and less persistent fruit (Moran & Fleger 1968).  These differences appear to be derived from a holacanthoid line, rather than within a Castela-Holacantha complex.  Awaiting molecular studies, the taxonomy here follows my preference, which would have been to include C. polyandra in Holacantha rather than to combine the two genera.  Also,  the Galapagos species (C. galapageia) that was included under Castela erecta by Cronquist (1945) is recognized as a species rather than a subspecies.  The Galapagos species from what we observed on three islands in 1997 appears highly variable in which six forms had been formally recognized; however, Stewart (1915, Amer. J. Bot. 2: 279–288) had concluded, based on a thorough analysis of  leaf characters, that  these do not deserve taxonomic status.



Castela galapageia
Galápagos Islands,
Erect form, Isla Rabida
June 1997

Castela galapageia prostrate form
Galápagos Islands, Isla Santa Fe, June 1997

Castela polyandra
Gulf Coast, BCN


Castela peninsularis

Castela texana

Castela tortuosa

Holacantha emoryi
Near Phoenix, AZ
July 1995

Holacantha stewartii
Near Lajitas, TX
June 1996


Notes on Holacantha emoryi in California, see Andrew Sanders,t

USDA ARS Procurement of Holacantha emoryi

Castela polyandra was reportedly the basis for obtaining glaucarubolone in deriving other semi-synthetic analogs that have been mentioned in patent application  20030149096 and 20020193425 “Cancer chemopreventative compounds and compositions and methods of treating cancers” by Pezzuto, John M.; (River Forest, IL) ; McChesney, James D.; (Boulder, CO) ; Cuendet, Muriel Anne; (Chicago, IL) ; Helson, Lawrence; (Quaker Town, PA).

Additional Publications and Patents of Interest.

Grieco, P. A.; Moher, E. D.; Seya, M.; Huffman, J. C.; and Grieco, H. J. 1994. A Quassinoid (Peninsularinone) And a Steroid from Castela peninsularis.  Phytochemistry 37: 1451-1454.  Based on recollections obtained by World Botanical Associates, which were also leads developed by World Botanical Associates in collaboration with Paul Grieco, the chemical byproducts are reported in United States Patent US Patent 6573296 -US Patent 6573296 - Therapeutic quassinoid preparations with antineoplastic, antiviral, and herbistatic activity
Juned 3, 2003, by Grieco, Paul A.; (Gosport, IN) ; Morre, D. James; (West Lafayette, IN) ; Corbett, Thomas H.; (Gross Pointe Park, MI) ; Valeriote, Frederick A.; (Utica, MI). 

Calzado-Flores, C., E.M. Guardo-Touche, M., P. Carranza-Rosales & J.J. Segura-Luna.  1998. Anti-Trichomonic Activity of Castela texana.  Proc. West. Pharmacol. Soc. 41: 174-174

Grieco, P.A., Haddad, J., Pineiro-Nunez, M.M. and Huffman, J.C. 1999. New Quassinoids from the Twigs and Thorns of Castela polyandra.  Phytochemistry, 50, 637-645

Z. Guo,  S. Vangapandu, R.W. Sindelar, L.A. Walker and R.D. Sindelar . 2005.  Biologically Active Quassinoids and Their Chemistry: Potential Leads for Drug Design  Current Medicinal Chemistry, 2005, 12, 173-190.

Notes: Castela polyandra was reported by the NCI to have good activity in KB and P-388, but no USDA "active sheet" record was found for this species.  Recollections, however, were later obtained by the WBA for Dr. Paul Grieco at Indiana University.

Also, in June 1997, samples were obtained of Castela galapageia. The Director of the park and his assistant had given us permission to collect the samples, and were physically present when we collected the samples as requested by them.  Based on lengthy discussions between the WBA and Ecuadorian authorities, a signed agreement by World Botanical Associates and Indiana University was sent to the Director of the National Park for his signature.  The Ecuadorian authorities, however, did not return the agreement, nor did they send the plant materials as mutually agreed upon during our visit.