©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
May 2004, Dec 2007



Croton californicus
Palm Springs, CA
Spjut 15732, Mar 2004

Croton californicus
Yuma Co. AZ. Barr 66-40, 30 May 1966


Croton dioicus
Hudspeth Co., TX, Oct 2007


Croton fruticulosus
South of Lordburg, NM, Oct 2007

Croton incanus
Amistad Natl. Rec. Area, TX
Spjut & Marin 15159, Nov 2002

Croton pottsii
Blackgap Wildlife Management Area, TX, Oct 2007


Croton wigginsii
Imperial Co., Algodones Sand Dunes, CA




Trees and Shrubs of Kern County (Jan 2013)

     Croton. Usually perennial, herbs or shrubs or trees, often with resinous sap but not milky latex, which is not evident in California species; hairs usually present and branched; leaves mostly alternate, or appearing nearly opposite or whorled in some species; flowers not in cyathia, usually sessile or pedicelled on simple axillary or terminal scapes (flower shoots, inflorescences); petals usually present in male flowers, reduced or absent in female flowers; fruit as generally described for the family, but in some species only one carpel matures.  >1200 species, usually a common constituent in most tropical and subtropical vegetation types.  3 species in California, 1 in Kern County.

Croton californicus Mueller-Argovensis 1866. California croton. Subshrub of wiry stems not more than 50 cm high and broad; leaves covered with branched (stellate) hairs; flowering Mar-Oct; flowers inconspicuous and falling off (without petals, calyx 1–2 mm). Common in sandy places near the coast in southern California north to the Bay Area, and in the deserts to southern Nevada, Arizona and Baja California. Type from San Francisco, CA. Kern Co. “ the desert and along the east side of the valley from Sand Ridge to Tejon Canyon” (Twisselmann).  CCH— Mojave Desert: Rogers Lake, southwest end of Edwards Air Force Base; Hwy 395 north of El Paso Mts.  San Joaquin Valley: Bakersfield; Sand Ridge; Tejon Creek Wash near Arvin; Buttonwillow Ranch; Hwy 99 4.6 miles north of Maricopa. Tehachapi Mts.: Ft. Tejon; Grapevine Creek.  Sierra Nevada: Caliente Wash; near Woodford; hot springs north of Kernville. 106–1006 m.


USDA ARS Procurement Records for Antitumor Active Species of Croton.

Croton californicus

Croton punctatus

     Memorandum on taxonomy of Croton punctatus, Aug, 2, 1973.

Croton texensis

Farnsworth N. R., R. N. Blomster, W. M. Messmer, J. C. King, G. J. Persinos and J. D. Wilkes. 1969. A phytochemical and biological review of the genus Croton. Lloydia 32(1): 1–28.

Soejarto D. D., A. D. Kinghorn and N. R. Farnsworth.  1977.  Allergic contact dermatitis from croton. Contact Dermatitis 3(5): 276.

Williams L. 3rd, P. E. Evans and W. S. Bowers. 2001. Defensive chemistry of an aposematic bug, Pachycoris stallii Uhler and volatile compounds of its host plant Croton californicus Muell.-Arg.  “Volatile components of Pachycoris stallii scent gland secretions and the bug's host plant, Croton californicus, were identified by gas chromatography and mass spectroscopy. The predominant compounds isolated from C. californicus fruit and leaves were beta-myrcene and beta-caryophyllene. Metathoracic gland secretions of P. stallii contained mostly (E)-2-hexenal, (E)-4-oxo-2-hexenal, (E)-2-hexenyl acetate, and n-tridecane. In males, n-tridecane was present throughout the metathoracic gland, but in females this compound was found only in the median reservoir/accessory gland. (E)-2-Hexenal was present throughout the gland of female bugs, but in males was primarily present in the median reservoir/accessory gland. (E)-4-Oxo-2-hexenal and n-dodecane were isolated from the median reservoir/accessory gland of male and female bugs. Metathoracic glands were sexually monomorphic. Data from chemical analyses and anatomical observations suggest that dorsal abdominal glands of adults were apparently obsolescent. In nymphs, dorsal abdominal glands produced (E)-2-hexenal, (E )-4-oxo-2-hexenal, n-dodecane, n-tridecane, and tetradecanal. The proportion of the predominant constituent, (E)-4-oxo-2-hexenal, decreased from 72% in the first instar to 47% in the fourth instar. Proportions of tetradecanal and n-tridecane were greater in the fourth instar than in the first instar. Observations of dissected glands indicated that median and posterior dorsal abdominal glands of all nymphal instars were more developed than anterior dorsal abdominal glands. Scanning electron micrography revealed the presence of polygonal microsculpturing on the integument surrounding the ostioles of metathoracic and dorsal abdominal glands. Chemical, anatomical, and behavioral data indicated that P. stallii has a chemical defense system based on short-chain carbonyl compounds and that this system is directed against arthropods. The abundance of arthropod natural enemies apparently has forced P. stallii to maintain this defense system despite feeding on a toxic host plant.”