Jepson eFlora: Taxon page
Key to families | Table of families and genera
Previous taxon Index to accepted names and synonyms:
| A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Next taxon
Toxicodendron diversilobum
WESTERN POISON OAK

Higher Taxonomy
Family: AnacardiaceaeView DescriptionDichotomous Key

Common Name: SUMAC or CASHEW FAMILY
Habit: Shrub, tree; generally dioecious or flowers bisexual and unisexual; resin clear, often weathering black, generally aromatic, latex milky or 0. Leaf: simple to ternate- or odd-pinnate-compound, alternate, deciduous or evergreen; stipules 0. Inflorescence: raceme or panicle; flowers generally many. Flower: generally unisexual, radial; sepals generally 5, base generally +- fused; petals 5, generally > sepals, free; (perianth parts 1--7 in Pistacia); stamens 4--7 or 10, vestigial in pistillate flowers; ovary superior, vestigial or 0 in staminate flowers, subtended by +- lobed, disk-like nectary, chamber generally 1, ovule generally 1, styles 1--3. Fruit: drupe-like, generally +- flat, sticky or not, hairs short or 0; pulp +- resinous, aromatic or not.
Genera In Family: 70+ genera, +- 850 species: tropics, warm temperate; some ornamental (Rhus, Schinus), cultivated for fruit (Anacardium, cashew; Mangifera, mango; Pistacia, pistachio). Toxicity: TOXIC: many genera produce contact dermatitis.
eFlora Treatment Author: John M. Miller & Dieter H. Wilken, except as noted
Scientific Editor: Bruce G. Baldwin, Thomas J. Rosatti.
Genus: ToxicodendronView Description 

Common Name: POISON OAK, POISON IVY
Habit: Shrub, vine-like or not; generally dioecious. Leaf: +- resinous; leaflets 3--9, thin to +- leathery, entire, toothed, or lobed. Inflorescence: raceme or panicle, axillary, +- open; flowers pedicelled. Flower: stamens 5, vestigial in pistillate flowers; styles +- fused, stigmas 3. Fruit: generally spheric, papery or leathery in age, cream to brown; pulp resinous.
Species In Genus: 15 species: America, eastern Asia. Etymology: (Latin: poisonous tree) Toxicity: TOXIC: resin on leaves, stems, fruits causes severe contact dermatitis; one of the most hazardous plants in California.

Toxicodendron diversilobum (Torr. & A. Gray) Greene
NATIVE
Habit: Shrub, 0.5--4 m, or vine-like, < 25 m. Stem: twigs gray- to red-brown, tapered, hairs 0 to sparse. Leaf: petiole 1--10 cm; leaflets 3(5), +- round to oblong, entire, wavy, or +- lobed, thin to +- leathery, bright red in fall, adaxially glabrous, shiny, abaxially sparse-short-hairy, base truncate to rounded, tip obtuse to rounded; terminal leaflet 1--13 cm, 1--8 cm wide, lateral 1--7 cm, 1--6 cm wide. Inflorescence: branches loose, generally arched, slender; pedicels 2--8 mm; bractlets < 1 mm. Flower: sepals green; petals > sepals, generally ovate, yellow- to white-green. Fruit: 1.5--6 mm diam, spheric to +- compressed, glabrous to fine-bristly, creamy white, in age leathery; pulp white, black-striate. Chromosomes: 2n=30.
Ecology: Canyons, slopes, chaparral, coastal scrub, oak woodland; Elevation: < 1650 m. Bioregional Distribution: CA-FP, sw edge DMoj; Distribution Outside California: to British Columbia, western Nevada, northern Baja California. Flowering Time: Apr--Jun
Synonyms: Rhus diversiloba Torr. & A. Gray
Unabridged Note: A related sp., Toxicodendron rydbergii (Small ex Rydb.) Greene, occurs in southeastern Oregon, Nevada, Utah, western Arizona.
eFlora Treatment Author: John M. Miller & Dieter H. Wilken
Jepson Online Interchange

Previous taxon: Toxicodendron
Next taxon: Apiaceae (Umbelliferae)

Name Search
botanical illustration including Toxicodendron diversilobum

Contact/Feedback

Citation for this treatment: John M. Miller & Dieter H. Wilken 2016. Toxicodendron diversilobum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=46791, accessed on April 30, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on April 30, 2016.


Toxicodendron diversilobum
click for enlargement
© 2004 George W. Hartwell
Toxicodendron diversilobum
click for enlargement
© 2007 Neal Kramer
Toxicodendron diversilobum
click for enlargement
© 2008 Thomas Stoughton
Toxicodendron diversilobum
click for enlargement
© 2010 Thomas Stoughton
Toxicodendron diversilobum
click for enlargement
© 2012 Gary A. Monroe
Toxicodendron diversilobum
click for enlargement
© 2014 Keir Morse

More photos of Toxicodendron diversilobum in CalPhotos


Geographic subdivisions for Toxicodendron diversilobum:
CA-FP, sw edge DMoj;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
READ ABOUT YELLOW FLAGS
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

View elevation by latitude chart
Data provided by the participants of the Consortium of California Herbaria.
View all CCH records

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.