©The World Botanical Associates Web Page
Prepared by Richard W. Spjut
May 2004, Nov. 2005; June 2006, Nov 2007, Jan 2013

Rhus aromatica var. pilosissima
Gila NF, NM, Spjut 16161, Oct 2007
Plants generally spreading at base by short rhizomes, forming rounded thickets, stems hardly monopodial, not strongly woody, leaves conspicuously pilose.  Common in oak savanna.


Rhus trilobata
Gila NF, NM, Spjut 16162, Oct 2007.  A less common form that was found with the preceding species, not rhizomatous, but with a more definite centralized stem that does not appear to die off with age but rather it becomes more woody.

Rhus glabra
UT: Fishlake NF, E of Fillmore, Sep 2007

Rhus integrifolia
N of Santo Tomas, BCN,
Spjut & Marin 11921, May 1990


Rhus lentii
Vizcaíno Peninsula, BCS
Spjut, McCloud & Marin 9611, May 1986


Rhus natalensis, Mt Londiani, Kenya, Spjut & Ensor 3190




Rhus microphylla
Black Gap Wildlife Refuge, TX
Spjut & Marin14448, Sep 2001



Rhus ovata
San Diego Co., Valley Center, CA
November 2005

Rhus trilobata
San Bernardino Co., Clark Mt., CA
June 2006

Gallic acid, active in KB, was reportedly isolated by Pettit from a sample of this species (Hartwell 1976).


Rhus trilobata
Arizona Desert, Prescott Natl. For.
9 Apr 2008, SPJ-16249


Rhus virens
Big Bend Natl. Park, TX
Spjut & Marin15131, Nov 2002


Trees and Shrubs of Kern County (Jan 2013)

Rhus ovata S. Watson 1885. Sugar bush. Evergreen shrub or small tree to 10 m; twigs thick, reddish; leaves alternate, thick, leathery, shiny green, folded upwards partway along midrib, lateral veins raised; flowers Mar–May, numerous on terminal branched scapes, pinkish white; fruit a reddish hairy drupe. Primarily chaparral in the Peninsular and Transverse Ranges on south-facing slopes below 4,000 ft to Tres Virgenes in Baja California. Type from hills and mountains away from the coast...locality not specific.  Sugarbush chaparral recognized in MCV2 when >30% relative cover in the shrub canopy with coastal sage scrub or desert species. Kern Co.: “near Bakersfield” (L. Saylor, 21 Mar 1935). A collection by V. Rutherford (Jul 1948) from Tehachapi Mts. in Canton Canyon of the Liebre Mountains region, vicinity of Castaic, is in Los Angeles Co (CCH). Not in Twisselmann.

Rhus trilobata Nuttall 1838 (excludes Rhus aromatica Aiton 1789). Skunkbush, basket bush.  Shrub up to 1.5 m high with coarse branches that curve downwards, especially near the tips, and with a strong scent when broken; leaves alternate, divided into three leaflets, the terminal leaflet not stalked, the leaflets turning red in fall and deciduous in winter; flowers appearing in the spring before the leaves; fruits grape-size, reddish orange, sticky drupes.  Variable and widely distributed shrub in the western U.S. Type from the Rocky Mts. Basket bush thickets provisionally recognized in MCV2.  Kern Co.  Scarce: 3 mi E of Woody along Spring Creek; near Keene (ECT and CCH), also on the Tejon Ranch Conservancy.

In JM2
Rhus trilobata is included under R. aromatica.  As noted under the images above, the two species were considered distinct where found growing in the same area in New Mexico, and where samples of both were collected for antitumor screening. They differ by their habit and vegetative reproduction. Rhus aromatica is often much broader than tall, forming nearly flat-topped rounded subshrubs with many erect fuzzy soft stems without a definite central stem at the base, the erect stems that evidently arise from rhizomes produce short branches at regular intervals.  I have seen this species in this form commonly in Texas and Oklahoma.  Rhus trilobata differs by having a well defined central base from a definite root from which one or more erect woody stems arise. They are more irregularly branched appearing also less fuzzy. It was possible to collect a root sample of R. trilobata in New Mexico, and a stem-bark sample in Arizona. Neither of these plant parts could be easily obtained from R. aromatica.  These differences may not be discernable in herbarium specimens.  The species varies from a much-branched small shrub less than 1 m high as seen in Modoc County to a tree as seen in southwestern Nevada.


Pharmacological References

Gu Q., R. R. Wang, X. M. Zhang, Y.H. Wang, Y.T. Zheng, J. Zhou and J.J.Chen. 2007. A new benzofuranone and anti-HIV constituents from the stems of Rhus chinensis. Planta Med. 73(3): 279–282. “A new benzofuran lactone, rhuscholide A (1), was isolated from the stems of Rhus chinensis, together with six known compounds: 5-hydroxy-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3 H)-benzofuranone (2), betulin (3), betulonic acid (4), moronic acid (5), 3-oxo-6 beta-hydroxyolean-12-en-28-oic acid (6) and 3-oxo-6 beta-hydroxyolean-18-en-28-oic acid (7). Based on 1D, 2D NMR (COSY, HMQC, HMBC) and mass (EI-MS, HR-EI-MS) spectral data, the structure of rhuscholide A was deduced to be 5-hydroxy-3-(propan-2-ylidene)-7-(3,7,11,15-tetramethylhexadeca-2,6,10,11-tetraenyl)-2(3 H)-benzofuranone (1). Anti-HIV-1 bioassays IN VITRO revealed that compound 1 possesses significant anti-HIV-1 activity with an EC50 value of 1.62 microM and a therapeutic index (TI) of 42.40. Compounds 2, 4, 5 and 7 showed moderate anti-HIV-1 activities with EC50 values of 3.70, 5.81, 7.49 and 13.11 microM, respectively.

Hong D. H., S. B. Han, C. W. Lee, S. H. Park, Y. J. Jeon, M. J. Kim, S. S. Kwak and H. M. Kim. 1999.  Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera Stokes). Arch. Pharm. Res. 22(6):638–641. “Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells.”

Jang H. S, S. H. Kook, Y. O. Son, J. G. Kim, Y. M. Jeon, Y. S. Jang, K. C. Choi, J. Kim, S. K. Han  R. Y. Lee, B. K. Park, N. P. Cho and J. C. Lee.  2005.  Flavonoids purified from Rhus verniciflua Stokes actively inhibit cell growth and induce apoptosis in human osteosarcoma cells.  Biochim. Biophys. Acta. 1726(3):309–316. “Many studies have suggested that dietary flavonoids are anticancer agents that induce the apoptosis of cancer cells. However, the effects of flavonoids on the induction of apoptosis in osteosarcoma cells are unclear. Previously, a flavonoid fraction, consisting mainly of protocatechuic acid, fustin, fisetin, sulfuretin, and butein, herein named RCMF (the RVS chloroform-methanol fraction), was prepared from a crude acetone extract of Rhus verniciflua Stokes (RVS). This study evaluated the effects of RCMF on the proliferation and apoptosis using human osteosarcoma (HOS) cells. The mechanism of growth inhibition of the HOS cells by the flavonoid fraction, RCMF, was also assessed. The results demonstrated that RCMF exhibited sensitive growth inhibition and induced apoptosis in HOS cells. PARP cleavage was closely associated with the RCMF-induced apoptosis of the HOS cells. Furthermore, the activation of caspase 8 and Bax, the inhibition of Bcl-2 expression, and the release of cytochrome c are believed to be involved in the RCMF-mediated apoptosis. Collectively, these findings suggest that RCMF is an agent which may be capable of inducing sensitive growth inhibition and apoptosis in HOS cells.”

Mdee L. K., S. O. Yeboah and B. M. Abegaz.  2003. Rhuschalcones II-VI, five new bichalcones from the root bark of Rhus pyroides.  J. Nat. Prod. 66(5): 599–604. “Biflavonoids detected in trace amounts in an earlier investigation of the twigs of Rhus pyroides have now been found in the root bark of this species. These new flavonoids belong to a rare bichalcone class and have been identified as 2',4',4' ',2' ",4' "-pentahydroxy-4-O-5' "-bichalcone (rhuschalcone II, 2), 2',4',4' ',2' "-tetrahydroxy-4' "-methoxy-4-O-5' "-bichalcone (rhuschalcone III, 3), 4,2',4' ',2' "-tetrahydroxy-4' "-methoxy-4'-O-5' "-bichalcone (rhuschalcone IV, 4), 4,2',4',4' ',2' ",4' "-hexahydroxy-3,5' "-dihydrochalcone-chalcone (rhuschalcone V, 5), and 4,2',4',4' ',2' ",4' "-hexahydroxy-3,5' "-bichalcone (rhuschalcone VI, 6), repectively. Also obtained was the known compound rhuschalcone I (1). Their structures were determined by spectroscopic and chemical methods, and for 1-3 by total synthesis. All the bichalcones (1-6) tested exhibited selective cytotoxic activity against the HT29 and HCT-116 colon tumor cell lines.”

Pettit G. R., E. I. Saldana and E. Lehto. Antineoplastic agents 35. 1974.  Rhus trilobata.
Lloydia 37(3): 539–540.

Rayne S. and G. Mazza. 2007. Biological Activities of Extracts from Sumac (Rhus spp.): A Review. Plant Foods Hum Nutr. 62(4):165–175. .“Sumac is the common name for a genus (Rhus) that contains over 250 individual species of flowering plants in the family Anacardiaceae. These plants are found in temperate and tropical regions worldwide, often grow in areas of marginal agricultural capacity, and have a long history of use by indigenous people for medicinal and other uses. The research efforts on sumac extracts to date indicate a promising potential for this plant family to provide renewable bioproducts with the following reported desirable bioactivities: antifibrogenic, antifungal, antiinflammatory, antimalarial, antimicrobial, antimutagenic, antioxidant, antithrombin, antitumorigenic, antiviral, cytotoxic, hypoglycaemic, and leukopenic. As well, the bioactive components can be extracted from the plant material using environmentally benign solvents that allow for both food and industrial end-uses. The favorable worldwide distribution of sumac also suggests that desirable bioproducts may be obtained at the source, with minimal transportation requirements from the source through processing to the end consumer. However, previous work has focussed in just a few members of this large plant family. In addition, not all of the species studied to date have been fully characterized for potential bioactive components and bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better understand the full potential of the Rhus genus as part of global green technology based on bioproducts and bioprocesses research programs.”

Samoszuk M., J. Tan and G. Chorn.  2005. The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts.  BMC Complement Altern Med. Mar 9; 5:5. “BACKGROUND: Butein (3,4,2',4'-tetrahydroxychalone), a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the growth of breast cancer cells, we investigated the ability of butein to inhibit the clonogenic growth of small numbers of breast cancer cells co-cultured with fibroblasts in vitro. METHODS: We first measured the clonogenic growth of small numbers of the UACC-812 human breast cancer cell line co-cultured on monolayers of serum-activated, human fibroblasts in the presence of butein (2 microg/mL) or various other modulators of fibroblast function (troglitazone-1 microg/mL; GW9662-1 microM; meloxican-1 microM; and 3,4 dehydroproline-10 microg/mL). In a subsequent experiment, we measured the dose-response effect on the clonogenic growth of UACC-812 breast cancer cells by pre-incubating the fibroblasts with varying concentrations of butein (10 microg/ml-1.25 microg/mL). Finally, we measured the clonogenic growth of primary breast cancer cells obtained from 5 clinical specimens with normal fibroblasts and with fibroblasts that had been pre-treated with a fixed dose of butein (2.5 microg/mL). RESULTS: Of the five modulators of fibroblast function that we tested, butein was by far the most potent inhibitor of clonogenic growth of UACC-812 breast cancer cells co-cultured with fibroblasts. Pre-treatment of fibroblasts with concentrations of butein as low as 2.5 microg/mL nearly abolished subsequent clonogenic growth of UACC-812 breast cancer cells co-cultured with the fibroblasts. A similar dose of butein had no effect on the clonogenic growth of breast cancer cells cultured in the absence of fibroblasts. Significantly, clonogenic growth of the primary breast cancer cells was also significantly reduced or abolished when the tumor cells were co-cultured with fibroblasts that had been pre-treated with a fixed dose of butein. CONCLUSION: We conclude that fibroblasts pre-treated with non-toxic doses of butein (a natural herbal compound) no longer support the clonogenic growth of small numbers of primary breast cancer cells seeded into co-cultures. These results suggest that interference with the interaction between fibroblasts and breast cancer cells by the natural herbal compound, butein, should be further investigated as a novel experimental approach for possibly suppressing the growth of micrometastases of breast cancer.”

Wu P. L., S. B. Lin, C. P. Huang and R. Y. Chiou.  2002. Antioxidative and cytotoxic compounds “extracted from the sap of Rhus succedanea. J. Nat. Prod. 65(11): 1719–1721. “Two new antioxidative and cytotoxic compounds, 10'(Z),13'(E),15'(E)-heptadecatrienylhydroquinone (1) and 10'(Z),13'(E)-heptadecadienylhydroquinone (2), as well as the known 10'(Z)-heptadecenylhydroquinone (3), were isolated from an EtOH extract of the sap of Rhus succedanea. The structures were elucidated by spectral analyses. These compounds showed antioxidative and cytotoxic activities against five cancer cell lines.”

Yi T., A. J. Mille and J. Wen.  2004. Phylogenetic and biogeographic diversification of Rhus (Anacardiaceae) in the Northern Hemisphere.  Mol. Phylogenet. Evol. 33(3): 861–879.  “Sequences of internal transcribed spacers (ITS) of nuclear ribosomal DNA, the chloroplast ndhF gene, and chloroplast trnL-F regions (trnL intron, and trnL [UAA] 3' exon-trnF [GAA] intergenic spacer) were used for phylogenetic analyses of Rhus, a genus disjunctly distributed in Asia, Europe, Hawaii, North America, and Northern Central America. Both ITS and cpDNA data sets support the monophyly of Rhus. The monophyly of subgenus Rhus was suggested by the combined cpDNA and ITS data, and largely supported in the cpDNA data except that Rhus microphylla of subgenus Lobadium was nested within it. The monophyly of subgenus Lobadium was strongly supported in the ITS data, whereas the cpDNA data revealed two main clades within the subgenus, which formed a trichotomy with the clade of subgenus Rhus plus R. microphylla. The ITS and cpDNA trees differ in the positions of Rhus michauxii, R. microphylla, and Rhus rubifolia, and hybridization may have caused this discordance. Fossil evidence indicates that Rhus dates back to the early Eocene. The penalized likelihood method was used to estimate divergence times, with fossils of Rhus subgenus Lobadium, Pistacia and Toxicodendron used for age constraints. Rhus diverged from its closest relative at 49.1+/-2.1 million years ago (Ma), the split of subgenus Lobadium and subgenus Rhus was at 38.1+/-3.0 Ma. Rhus most likely migrated from North America into Asia via the Bering Land Bridge during the Late Eocene (33.8+/-3.1 Ma). Rhus coriaria from southern Europe and western Asia diverged from its relatives in eastern Asia at 24.4+/-3.2 Ma. The Hawaiian Rhus sandwicensis diverged from the Asian Rhus chinensis at 13.5+/-3.0 Ma. Subgenus Lobadium was inferred to be of North American origin. Taxa of subgenus Lobadium then migrated southward to Central America. Furthermore, we herein make the following three nomenclatural combinations: (1) Searsia leptodictya (Diels) T. S. Yi, A. J. Miller and J. Wen, comb. nov., (2) Searsia pyroides (A. Rich.) T. S. Yi, A. J. Miller and J. Wen, comb. nov., and (3) Searsia undulata (Jacq.) T. S. Yi, A. J. Miller and J. Wen, because our analyses support the segregation of Searsia from Rhus.”