Introduction to the Anacardiaceae Family

The Anacardiaceae family is part of the Sapindales Order of core Eudicots. The Anacardiaceae family is well known for the various species of Sumac (Rhus spp) and Poison Ivies (Toxicodendron spp) that we have throughout North America. The Sumac trees are often used ornamentally for their ease of growing and their pretty red drupes that persist all winter. Poison Ivy is well known to anyone who has ever hiked in the forest since it causes very itchy contact dermatitis. 

There is an old saying, “leaves of three let it be” since all of the Toxicodendron species that cause poison ivy rash have trifoliate leaflets. It is a good rule of thumb if you are unsure of your plant ID. But be aware that numerous innocuous species exist that also have trifoliate leaves, so do not assume it is always a poison ivy. Poison ivy (shrub forms) can also be mistaken for young oaks at times because the leaves often resemble those of the White Oak.

Flowers of the Anacardiaceae

Plants can be hermaphrodite, monoecious, dioecious, gynodioecious, or polygamomonoecious. Pollination when heterantherous is entomophilous.  Flowers are aggregated in racemose panicles. Flowers are small, regular, usually 5 merous, and either tetracyclic or pentacyclic. Free hypanthium is either absent or present but short. A hypogynous disk is present, intrastaminal and annular. The perianth has a distinct calyx and corolla or may be sepaline. The perianth has 3–5 or 6–10 parts in 1 or 2 whorls and is isomerous. Calyx has 3–5 parts in 1 whorl, is basally connate, often with cleft sepals, and lobes are shorter to longer than the tube. The calyx is regular and imbricate. The corolla, when present, has 3–5 parts in 1 whorl, is usually free but rarely can be connate basally, the lobes are longer than the tube, and it is imbricate.

Androecium of the Anacardiaceae

The androecium has 5–10(11–12) parts. Androecial members are free of the perianth and may be free of one another or coherent 1 adelphous (the filaments are sometimes basally connate). The members may be all equal or unequal and can be either 1 or 2 whorled. Androecium may or may not include staminodes. When present, there are 1-9 staminodes. There are 5–10(1–12) stamens, they are oppositisepalous, inserted at the base of the hypogynous disc, and are usually equal in number or twice as many as the petals. Anthers are usually dorsifixed or sometimes basifixed (Spondias), they are versatile, dehiscing via longitudinal slits, introrse, and tetrasporangiate.

Gynoecium of the Anacardiaceae

The gynoecium is usually 5 carpelled but can be 1–6 carpelled, and the pistil is 1–5 celled. The gynoecium is synovarious or synstylovarious, or rarely semicarpous. It is usually superior or sometimes partly inferior. The ovary is 1–5 locular. There is usually one style, but there may be 3–6 styles, and in Buchanania, it has up to five styles from sterile carpels. There are 1-5 stigmas, they are wet type, non-papillate, and Group IV type. Placentation, when unilocular, is parietal or basal, and when bi- or plurilocular, it is basal. There is 1 ovule per locule, it is pendulous or ascending, has either ventral or dorsal raphe, is non-arillate, anatropous, unitegmic or bitegmic, and crassinucellate. 

Fruit of the Anacardiaceae

The fruit is usually a fleshy drupe, but sometimes it is an indehiscent non-fleshy dry fruit. The drupes have one stone, rarely open at maturity, and sometimes contain urushiol, a toxic irritant found in poison ivy and other species. Seeds are non-endospermic.

Habit & Leaf Form of the Anacardiaceae

Trees or shrubs, self-supporting or climbing, sometimes with a milky juice that may be resinous or laticiferous. Leaves are persistent or deciduous, alternate spiral except in Bouea, where they are opposite, herbaceous, and aromatic when resinous but otherwise odorless. They are simple or compound ternate, trifoliate, imparipinnate, or rarely paripinnate or bipinnate. Primary venation is pinnate or rarely palmate. Secondary venation is eucamptodromous, brochidodromous, craspedodromous, cladodromous, or rarely reticulodromous.  If present, cladodromous venation is diagnostic for the Anacardiaceae family. Leaves are exstipulate. Lamina margins are entire. Domatia occur in 8 genera as pits, pockets, or hair tufts. Resin canals located in the inner fibrous bark and pith of the stems, roots, and leaves are characteristic of this family. Tannin sacs are very common.

Uses of Anacardiaceae 

Some Anacardiaceae are edible plants such as cashew nuts (Anacardium, and the fleshy peduncle of the cashew-apple), mango (Mangifera), Jamaica plum, hog-plum, imbu (a plum-like fruit from Spondias), Amarula cream (from Sclerocarya typically made into a liqueur). Resins, oils, and lacquers are derived from Toxicodendron. Several non-native Anacardiaceae are cultivated in the Neotropics for their edible fruits, including Bouea macrophylla,, Harpephyllum caffrum, Mangifera indica, Schinus terebinthifolia, Sclerocarya birrea subspecies caffra, and Spondias dulcis.  Many Anacardiacea species are notorious for their allergenic properties that often cause severe rashes, particularly Toxicodendron spp. (Poison Oak, Poison Ivies).

Morphology of Anacardiaceae in North America

Anacardiaceae Species I have Covered So Far

Anacardioideae Subfamily

Mangifera indica – Mango

A 10 – 20m tall tree with long oblong leaves and large edible drupes fruits on very long peduncles. Native to Asia but widely cultivated in southern North America, especially in Mexico.

Rhus aromatica – Fragrant Sumac

A somewhat lemon-scented shrub with trifoliate lobed leaves and hairy red drupes. Dioecious with small inconspicuous flowers. Native throughout USA, Mexico, and southeastern Canada.

Rhus copallinum – Shining Sumac

A tall shrub with glossy odd-pinnate leaves that have a conspicuously winged rachis or petiolules. Native to eastern North America, often cultivated.

Rhus glabra – Smooth Sumac

A tall shrub with hairless branches and odd-pinnate leaves with 11 – 31 acuminate serrated leaflets. Produces large dense panicles of red drupes. Native to eastern North America with scattered populations in western North America.

Rhus microphylla – Littleleaf Sumac

A desert shrub that often flowers before its tiny odd-pinnate glossy green, leathery, hairy leaves emerge. Fruits are clusters of small hairy drupes. Native to southwestern USA plus north and central Mexico.

Rhus trilobata – Skunkbush Sumac

Gets a bad rap for its pungent bitter scent, but it is not as unpleasant as a skunk. It is a shrub with trifoliate lobed leaves, and flowers in catkins, and its fruits are hairy sticky red drupes. Native to western North America, including western Mexico.

Rhus typhina – Staghorn Sumac

A large shrub with odd-pinnate leaves with 9 – 31 serrated leaflets; stems and petioles are densely red-hairy (unlike R. glabra). Native to northeastern USA and southeastern Canada.

Searsia lancea – African Sumac or Willow Rhus

Tree from Africa with pendulous twigs and narrow willow-like leaves. Occasionally cultivated in the southern USA and Mexico.

Toxicodendron pubescens – Atlantic Poison Oak

A perennial shrub to 1 m tall with variable trifoliate alternate pubescent leaves that are often irregularly lobed. Causes contact dermatitis. Native to southeastern USA west to OK and TX.

Toxicodendron radicans – Eastern Poison Ivy

A climbing vine (sometimes a shrub) with woody stems & trifoliate shiny leaves that are usually not serrated. Flowers are small greenish, and inconspicuous. The fruit is a gray-white drupe. Causes contact dermatitis. Native to eastern USA and Canada.

Toxicodendron rydbergii – Western Poison Ivy

A shrub with opposite trifoliate leaves that are often asymmetrical. The fruits are white, yellow, or brown drupes that are ribbed. Native throughout USA and Canada but mostly found in the west.

Taxonomy of the Anacardiaceae Family

The Anacardiaceae has about 938 spp in 79 genera of the Sapindales Order of core Eudicots. There are two accepted subfamilies with several dissident genera in their own groups or unplaced, here I have put them all as “unplaced in a subfamily.” As APG updates these, this record will be updated to reflect any changes.

1. Anacardioideae – Trees or shrubs with black or colored resinous exudate and crystals are present in the xylem. Leaflets are not articulated, margins are usually entire, and the base of the petiole is often swollen. Flowers are 5(-7)-merous, the calyx is more or less connate basally, the gynoecium is typically 3 carpelled, and the stigma is dry and capitate or lobed. The fruit is a drupe that is layered with a crystalliferous endocarp.  
2. Spondiadoideae – Deciduous trees or shrubs that typically cause contact dermatitis. Flower pedicels are often articulated, the gynoecium is 4-5(3) carpelled, and the stigma is only slightly expanded. Fruit is usually more than two-seeded (but sometimes only one), its pericarp may or may not have a lacuna, and the inner mesocarp is made of encircling fibers.

Unplaced includes the Sclerocarya complex of multiple genera, plus Buchanania and Campnosperma that are grouped together, and some completely unplaced ones, including Attilaea, Haplospondias, Koordersiodendron, and Pentaspadon.

Genera:

Anacardioideae: Abrahamia (34), Actinocheita (1), Amphipterygium (5) Anacardium (20), Androtium (1), Astronium (11), Baronia (1), Blepharocarya (2), Bonetiella (1), Bouea (3), Campylopetalum (1), Cardenasiodendron (1), Comocladia (27), Cotinus (7), Dobinea (2), Drimycarpus (4), Euroschinus (9), Faguetia (1), Fegimanra (3), Gluta (35), Haplorhus (1), Heeria (1), Holigarna (9), Laurophyllus (1), Lithraea (3), Loxopterygium (4 inc Apterokarpos), Loxostylis (1), Malosma (1), Mangifera (63), Mauria (15), Melanochyla (23), Metopium (4), Micronychia (10), Mosquitoxylum (1), Myracrodruon (2), Nothopegia (10), Ochoterenaea (1), Orthopterygium (1), Ozoroa (46), Pachycormus (1), Parishia (8), Pegia (2), Pistacia (11), Protorhus (3), Pseudosmodingium (5), Rhodosphaera (1), Rhus (54), Schinopsis (7), Schinus (32), Searsia (110), Semecarpus (87), Smodingium (1), Sorindeia (10), Swintonia (13), Thyrsodium (6), Toxicodendron (27), Trichoscypha (33).

Spondiadoideae: Allospondias (2), Dracontomelon (9), Haematostaphis (1), Pseudospondias (2), Sclerocarya (2), Solenocarpus (2), Spondias (18), Tapirira (9).

Unplaced in a subfamily: Antrocaryon (5), Attilaea (1), Buchanania (26), Campnosperma (14), Choerospondias (1), Cyrtocarpa (5), Harpephyllum (1), Koordersiodendron (1), Lannea (36), Operculicarya (9), Pentaspadon (6), Pleiogynium (3), Poupartia (7), Poupartiopsis (1).

Key Differences From Similar Families

The Anacardiaceae differs from the similar Burseraceae by having usually alternate or sub-opposite leaves or leaflets compared to the almost always opposite leaflets of Burseraceae.

Distribution of Anacardiaceae

The Anacardiaceae family is mainly tropical to subtropical, with a few important genera found in temperate North America. They are widespread pantropically and also in the Mediterranean, eastern Asia, and the warm Americas.

Distribution of Anacardiaceae in the Americas

Canadian Genera Include:

Anacardioideae: Cotinus 1 of 7 NAM & Eurasian sp intro ON; Rhus 5 of 54 Americas, Mediterranean & S+SE Asia spp native all S provinces exc NL; Toxicodendron 3(4) of 27 Americas & S+E Asia spp native all S provinces except NL, inc YT. 

USA Genera Include:

Cotinus 2 of 7 NAM & Eurasian spp inc 1 sp C+E USA endemic and 1 sp intro UT, TX, OK, AR, IL, MO, AL, GA, TN, KY, OH, PA, NY, MD, DE, NJ, CT, MA, VT;Lithraea 1 spp intro CA; Malosma monospecific S NAM endemic native CA; Mangifera 1 of 63 SE & Tropical Asia spp intro FL; Metopium 1 of 4 Mexican & Caribbean endemic spp native FL; Pistacia 3 of 11 pantropical spp inc 1 sp native TX and 2 spp intro CA, UT, OK, AL, GA, VA; Rhus 16 of 54 Americas, Mediterranean & S+SE Asia spp native and intro in the entire US inc HI (exc AK); Schinus 5 of 32 former SAM endemic spp intro CA, TX, AL, FL, and HI; Toxicondrendon 5 of 27 Americas & S+E Asia spp native in all USA.  Spondiadoideae: Spondias 1 of 18 pantropical spp intro FL. 

Mexico Genera Include:

Actinocheita monospecific Mesoamérica endemic of Honduras and Nay, Jal, Col, Mch, Gro, Oax, Pue; Amphipterygium 5 of 5 Mexico & N Neo endemic spp native most of Mexico exc NW Mexico, inc 2 endemics of SW Mexico (1), Dgo + Jal (1); Anacardium ?? of 20 former Neo endemic spp intro Nay, Jal, Col, Mch, Gro, Oax; Astronium 2 of 11 Mexico & Neo endemic spp native NE+SW+SE Mexico, Ver, inc 1 narrow endemic of Ver; Bonetiella monospecific endemic N to C Mexico; Comocladia 5 of 27 Mexico & N Neo endemic spp native in all of Mexico, inc 3 endemic to Mexico, 2 of which are narrow endemics of SW Mexico; Cotinus 3 of 7 NAM & Eurasian spp native Chi, Coa, NL, Tam, Dgo, Zac, Ags, Gto, Qro, Hgo, inc 2 spp endemic to Qro + SLP (1), Dgo + Coa (1); Lithraea 1 of 3 former Neo endemic sp native in Pue; Malosma monospecific S NAM endemic native BCN, BCS, Son, Sin, Chi, Coa, NL, Tam, SLP, Dgo, Zac, Mexican Pacific Islands; Mangifera 1 ?? of 63 SE & Tropical Asia spp intro SW+SE+C Mexico; Metopium 1 of 4 Mexican & Caribbean endemic spp native Ver, Chp, Cam, Tab, Yuc, QR; Mosquitoxylum monospecific N Neo endemic spp native S Mexico in Nay, Jal, Col, Mch, Gro, Oax, Chp, Ver, Tab, Cam, Yuc, QR; Pachycormus monospecific endemic of BCN, BCS; Pistacia 2 of 11 pantropical spp inc 1 sp native most of Mexico exc BC, BCS, Son, Sin and 1 sp intro N Mexico; Pseudosmodingium 5 of 5 spp endemic to most of Mexico exc SE Mexico; Rhus ?? of 54 Americas, Mediterranean & S+SE Asia spp native throughout Mexico inc Mexican Pacific Is; Schinus ?? of 32 former SAM endemic spp intro N and SW Mexico; Toxicodendron 4 of 27 Americas & S+E Asia spp native all of Mexico. Spondiadoideae: Spondias 3 of 18 pantropical spp native to all Mexico; Tapirira 2 of 7 Mexico & Neo endemic spp native SW Mexico, Pue, Ver, Cam, Tab, Yuc, QR, inc 1 narrow endemic of Oax + Ver. Unplaced: Attilaea monospecific recently published genus endemic to QR, Yuc & Guatemala?; Cyrtocarpa 3 of 5 Mexico & Neo endemic spp native most of Mexico exc Ver, inc 2 endemics of Mexico (1), SW+SE Mexico (1).

Neotropical Genera Include:

Anacardioideae: Actinocheita monospecific Mesoamerica endemic to SC Mexico, Honduras; Amphipterygium 3 of 5 Mexico & Neo endemic spp native Guatemala, Honduras, Nicaragua, NW Costa Rica; Anacardium 20 of 20 former Neo endemic spp native from Honduras S to Peru, Bolivia, Paraguay, S Brazil, Cuba and intro rest of Antilles (exc Netherlands Antilles & Aruba),  Belize, El Salvador, and pantropical; Apterokarpos (~Loxopterygium) endemic to the Caatinga of NE Brazil; Astronium 10 of 11 Mexico & Neo endemic spp native CAM S through tropical SAM to Peru, Bolivia, NE Argentina, S Brazil, inc 5 narrow endemics of Brazil (4), Trinidad-Tobago (1); Cardenasiodendron monospecific endemic to Bolivia; Comocladia 24 of 27 Mexico & N Neo endemic spp native Guatemala, Belize, Greater Antilles, Leeward & Windward Is, 15 spp are single island endemics of Jamaica (6), Hispaniola (5), Cuba (2), Dominican Republic (1), Haiti (1), inc 1 extinct sp of the Windward Is; Haplorhus monospecific endemic to the dry inter-Andean valleys of Peru to N Chile; Lithraea 3 of 3 Mexico & SAM endemic spp of C+E+S Brazil, Bolivia, Paraguay, N Argentina, Uruguay, C Chile and C Mexico, inc 1 narrow endemic of C Chile; Loxopterygium 4 of 4 SAM endemic spp of Venezuela, Guyana, Suriname, French Guiana, Ecuador, Peru, Bolivia, NW Argentina, NE Brazil, inc 1 narrow endemic of NE Brazil; Mangifera 1 of 63 SE & Tropical Asia spp intro Guatemala, Belize, Honduras El Salvador, Costa Rica, Galapagos, Antilles (exc Netherlands Antilles, Aruba), Venezuela, Ecuador, Peru, Paraguay, S Brazil; Mauria 15 of 15 Neo endemic spp native from Costa Rica S to Colombia, Venezuela, Ecuador, Peru, Bolivia, NW Argentina; Metopium 4 of 4 Mexican & Caribbean endemic spp native Guatemala, Belize, Honduras, Bahamas, Turks-Caicos, Antilles (exc Leeward Is & Venezuelan Antilles), SW Caribbean; Mosquitoxylum monospecific N Neo endemic of Jamaica, S Mexico, Guatemala, Belize, Honduras, Nicaragua, Panama, Ecuador; Myracrodruon 2 of 2 SAM endemic spp of Brazil, Bolivia, Paraguay, N Argentina; Ochoterenaea monospecific N SAM endemic, Andean Venezuela and Colombia, Bolivia, Panama?; Orthopterygium monospecific endemic to W Peru; Pistacia 1 of 11 pantropical spp native Guatemala, Honduras, absent SAM; Rhus ?? of 54 Americas, Mediterranean & S+SE Asia spp native Cuba, Bahamas, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, intro Trinidad-Tobago, absent SAM; Schinopsis 7 of 7 SAM endemic spp of Peru, Bolivia, C+E Brazil, Paraguay, N Argentina; Schinus 32 of 32 spp former SAM endemic spp native Peru, Bolivia,  C+E+S Brazil, Paraguay, Uruguay, Chile, Argentina, absent Amazonia, intro Ecuador, Colombia, Bermuda, Bahamas, Turks-Caicos, Cuba, Dominican Republic, Puerto Rico, Trinidad-Tobago, Venezuelan Antilles, Guatemala, El Salvador, Mexico & pantropical; Semecarpus 1 of 87 SE & Tropical Asia spp intro Trinidad-Tobago; Thyrsodium 6 of 6 spp N SAM endemic spp of Colombia, Peru, Bolivia, Venezuela, French Guiana, Guyana, Suriname, N+C+E Brazil, absent Andes; Toxicodendron 3 of 27 Americas & S+E Asia spp inc 2 spp native Bermuda, Bahamas, Guatemala, El Salvador, Honduras, Nicaragua, Panama, Colombia, Venezuela, Ecuador, Peru, Bolivia and 1 Asia sp intro Cuba. Spondiadoideae: Dracontomelon 1 of 9 tropical SE Asia spp intro Trinidad-Tobago; Spondias 12 of 18 pantropical spp inc 11 native Antilles, CAM S through tropical SAM S to Peru, Bolivia, C+SE Brazil, and 1 Asian spp intro Guatemala, Belize, Nicaragua, Panama, Greater Antilles, Colombia, Venezuela, Guyana, French Guyana, N+SE Brazil, Ecuador, Peru, inc 6 narrow endemics of E Brazil; Tapirira 10 of 11 Mexico & Neo endemic spp native CAM and tropical SAM S to Peru, Bolivia, Paraguay, S Brazil, inc 3 narrow endemics of Costa Rica (1), Colombia (1), French Guiana (1). Unplaced: Antrocaryon 1 of 5 otherwise Africa endemic spp is a N SAM endemic native to  Colombia, Amazonian N+C Brazil; Campnosperma 2 of 14 otherwise Madagascar & tropical SE Asia & Australasia spp are Neo endemics from Honduras S to Colombia, Venezuela, Ecuador, Peru and Amazonian N Brazil; Cyrtocarpa 2 of 5 Mexico + Neo endemic spp native Colombia, Venezuela, Guyana, N+C+E Brazil, Netherlands Antilles, inc 1 endemic of Brazil.

Patagonia Genera Include:

Anacardioideae: Lithraea 1 of 3 Mexico + SAM endemic spp native Bio Bio to Los Lagos C Chile; Schinus 6 of 32 former SAM endemic spp native Patagonia. 

Additional Information and References

• Visit Lyrae’s Dictionary of Botanical Terms to learn the terminology of botanists. Note that if you hover over most of the words in the articles you can also get definitions from them there.
• Willis, Lyrae (2023).  Plant Families of North America.  Not yet published. This is where all of the family descriptions come from. Below should be most of my references for this. Annonaceae, Orchidaceae, Poaceae, and Cyperaceae have additional references.
• Canadensys: Acadia University, Université de Montréal Biodiversity Centre, University of Toronto Mississauga, University of British Columbia. http://data.canadensys.net/explorer (accessed 2020 – current)
• Delta: Watson, L., and Dallwitz, M.J. 1992 onwards. The families of Flowering Plants: descriptions, illustrations, identification, and information retrieval. Version: 2nd May 2020. delta-intkey.com’. Accessed Spring through fall of 2020.
• GBIF.org (2020), GBIF Home Page. Available from: https://www.gbif.org
• Naturalista: CONABIO http://www.naturalista.mx Accessed 2020 – current.
• Neotropikey: Milliken, W., Klitgård, B. & Baracat, A. eds (2009 onwards). Neotropikey – Interactive key and information resources for flowering plants of the Neotropics. www.kew.org/neotropikey.com (accessed 2020 – current).
• Patagonia Wildflowers: Wildflower Identification Site. https://patagoniawildflowers.org/ Accessed throughout the fall of 2020.
• POWO (2019). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; http://www.plantsoftheworldonline.org/ Retrieved Winter 2020 – current.
• The Plant List (2013). Version 1.1. Published on the Internet; http://www.theplantlist.org/ (accessed 2020 to 2021). No longer updated. Use WFO below.
• USDA, NRCS. 2020. The PLANTS Database (http://plants.usda.gov, 2 June 2020). National Plant Data Team, Greensboro, NC 27401-4901 USA; accessed throughout fall of 2020.
• Wikipedia: The free encyclopedia. (2004, July 22). FL: Wikimedia Foundation, Inc. Retrieved throughout 2019-current, from https://www.wikipedia.org
• WFO (2022): World Flora Online. Published on the Internet; http://www.worldfloraonline.org. Accessed Spring 2022 – current