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Key to families | Table of families and genera

Previous taxon Indexes to all accepted names and synonyms:
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John M. Miller & Dieter H. Wilken, except as noted

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.
70+ genera, ± 850 species: tropics, warm temperate; some ornamental (Rhus, Schinus), cultivated for fruit (Anacardium, cashew; Mangifera, mango; Pistacia, pistachio). TOXIC: many genera produce contact dermatitis. [Yi et al. 2007 Syst Bot 32:379–391] —Scientific Editors: Bruce G. Baldwin, Thomas J. Rosatti.
Unabridged references: [Pell 2004 Ph.D. Dissertation, Louisiana State Univ, Baton Rouge; Cronquist et al. 1997 Anacardiaceae In: Intermountain Flora 3A:313–317; Wannan & Quinn 1991 Bot J Linn Soc 107:349–385; Wannan & Quinn 1990 Bot J Linn Soc 103:225–252; Ibe & Leis 1979 Bull Torrey Bot Club 106:140–144; Brizicky 1963 J Arnold Arbor 44:60–80]

Key to Anacardiaceae

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.
15 species: America, eastern Asia. (Latin: poisonous tree) TOXIC: resin on leaves, stems, fruits causes severe contact dermatitis; one of the most hazardous plants in California.
Unabridged references: [Yiet al. 2007 Syst Bot 32:379–391; Pell 2004 Ph.D. Dissertation, Louisiana State Univ, Baton Rouge; Cronquist et al. 1997 Anacardiaceae In: Intermountain Flora 3A: 313–317; Wannan & Quinn 1991 Bot J Linn Soc 107:349–385; Wannan & Quinn 1990 Bot J Linn Soc 103:225–252; Ibe & Leis 1979 Bull Torrey Bot Club 106:140–144; Gillis 1971 Rhodora 73:72–159, 161–237, 370–443, 465–540]

T. diversilobum (Torr. & A. Gray) Greene WESTERN POISON OAK
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.
2n=30. Canyons, slopes, chaparral, coastal scrub, oak woodland; < 1650 m. California Floristic Province, sw edge Mojave Desert; to British Columbia, western Nevada, northern Baja California. [Rhus diversiloba Torr. & A. Gray] Apr–Jun [Online Interchange]
Unabridged note: A related sp., Toxicodendron rydbergii (Small ex Rydb.) Greene, occurs in southeastern Oregon, Nevada, Utah, western Arizona.

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Citation for the whole project: Jepson Flora Project (eds.) 2013. Jepson eFlora,, accessed on Nov 25 2015
Citation for this treatment: [Author of taxon treatment] 2013. Toxicodendron, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on Nov 25 2015

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click for enlargement Toxicodendron diversilobum
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2004 David A. Tharp

Geographic subdivisions indicated for the distribution of Toxicodendron diversilobum 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.
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).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

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