Introduction to the Araliaceae Family

The Araliaceae family is best known for its most popular plant, Ginseng. But there are so many other lovely plants in this family. My personal favorite member of this family is Oplopanax horridus or Devil’s Club. Devil’s Club is typical of the family growing as a shrub with large leaves and small flowers in tall umbels followed by small red drupes. The Araliaceae are part of the Apiales order of core dicots and are very closely related to the Apiaceae family and have many overlapping characteristics. In general, however, the Apiaceae are usually herbs that produce dry schizocarps, while the Araliaceae are usually shrubs or trees and usually produce berry-like drupes. 

Flowers of the Araliaceae

Plants may be hermaphrodite, monoecious, andromonoecious, gynomonoecious, dioecious, or polygamomonoecious. Flowers are aggregated in spikes, heads, and sometimes umbels (compared to usual umbels in the Apiaceae).  Inflorescences are terminal, axillary, leaf-opposed, or rarely epiphyllous. Some genera have racemes, usually with umbels or heads, often massed into compound inflorescences. Flowers are usually more or less 5-merous, cyclic, and rarely calyptrate.  The floral receptacle has neither an androphore nor a gynophore. Perianth has a distinct calyx and corolla or may be petaline, has 10(6–24) parts, and is usually two-whorled and isomerous or anisomerous. In Meryta, it is one whorled where the calyx is entirely lacking. Calyx, when present, has 3–5(–12) parts, is one whorled, free or connate, entire, lobulate, blunt-lobed, or toothed when it is sometimes reduced to small teeth or a mere rim), and is often open when in bud. Corolla has 5(3–13) parts where partially divided or lobed segments sometimes complicate the interpretation of parts. It is one whorled and usually alternates with the calyx, with most genera having five sepals alternating with five petals (exceptions do occur). Corolla is free or partially connate at the base, is rarely calyptrate, may be valvate or imbricate (in Aralieae), is always regular, and is often fleshy.  Petals are usually sessile, often with broad bases inserted around the whole circumference of the upper part of the ovary) or sometimes they are clawed, as in Mackinleyeae.  

Androecium of the Araliaceae

The androecium has 5(3–12) or 10–100 members. Androecial members are free of perianth and one another, all are equal, and all are fertile. Stamens vary in number with 5(3–12) or 10–100, are usually isomerous with the perianth, inflexed in bud, and are filantherous with usually short and fleshy anthers. Stamens may alternate with the corolla members, usually when they equal them in number, or they may be opposite to the corolla members. Anthers are dorsifixed, dehisce via longitudinal slits, and introrse. Anthers are almost always tetrasporangiate (but occasionally appear bisporangiate by fusion during development) or multisporangiate in Octotheca and Dizygotheca.

Gynoecium of the Araliaceae

The gynoecium is 2–5(1–100) carpelled, and the pistil is 2–5(1–100) celled. The gynoecium is synovarious to syncarpous with the styles almost always forming a solid or sometimes hollow stylopodium. Or rarely, the gynoecium can appear monomerous in some Polyscias. It may be partly inferior to inferior or rarely superior (sometimes in Tetraplasandra). Carpel, when monomeric (rarely), is one ovuled with a second abortive ovule. The ovary is 1–100 locular. Locules have no false septa. The epigynous disk is present with a nectariferous disk between the stylopodium and stamens. The number of styles varies widely from 1–100. When there are two to more, then they are free or partially joined and apical. Stigmas are usually present as a frequently double stigmatic crest capping the stylopodium, are wet or dry type, papillate, and Group II and III types.   Placentation when bi/plurilocular (almost always) is axile to apical. When unilocular (rarely) parietal to apical. Ovules in the single cavity 1–2 (if two, then the second is usually abortive) per locule, pendulous, epitropous, with ventral raphe, anatropous, unitegmic, and usually crassinucellate or otherwise tenuinucellate.  

Fruit of the Araliaceae

Fruit may be fleshy or non-fleshy, often an indehiscent berry or drupe with separable pyrenes or with one stone (there are as many pyrenes as locules). Sometimes it will be a schizocarp with 2-5(6-100) mericarps. Gynoecia may combine to form multiple fruits. Seeds are endospermic, ruminate (e.g., Hedera) or not, and oily.

Habit & Leaf Form of the Araliaceae

Perennial trees of moderate size but occasionally very large with Peekeliopanax reaching 40 m high, arborescent, shrubs, woody epiphytes, lianas, or herbs (Panax, Stilbocarpa, some Aralia, etc.). They are non-laticiferous without colored juice, with or without essential oils, and resinous. Occasionally some are switch plants. Plants are green and photosynthesizing. Self-supporting, epiphytic, or climbing; when climbing may be stem twiners or root climbers. Almost always pachycaul with large leaves and thick stems, but sometimes they are leptocaul in Pseudopanax where long and short shoots are seen. Plants may or may not be conspicuously heterophyllous (sometimes e.g., Hedera helix where progression from lobed to entire leaves reflects irreversible shoot maturation). Leaves are usually medium to very large (to over 3 m in Aralia) or rarely small (1–2 cm in Pseudopanax anomalum). Their attachment to the stem is nearly always alternate, mostly spiral, or rarely distichous, four-ranked, opposite (Cheirodendron, Polyscias), or whorled (Panax). Leaves are often leathery, and usually petiolate or sometimes subsessile. They are usually more or less sheathing but may sometimes be non-sheathing, when sheathing, they have free margins. Leaves are gland-dotted or not, aromatic or odorless. Leaf shape is mostly simple (mostly) or compound ternate, pinnate, palmate, multiply compound, and sometimes peltate (some Harmsiopanax). Lamina, when simple, is usually dissected pinnatifid or palmatifid but may be entire. They are pinnately or palmately veined. Leaves may be stipulate or exstipulate. When stipules are present, they are intrapetiolar, often adnate to and scarcely distinguishable from the base of the petiole. Vegetative buds are scaly. Some taxa have spines (as in Oplopanax).

Uses of Araliaceae 

Ornamentals include the angelica tree (Aralia spinosa) and ivy (Hedera spp.) and houseplants such as Hedera, Aralia, Polyscias, Schefflera, Fatsia.  Plus medicinal herbs such as Ginseng roots from Panax quinquefolius and the devil’s club (Oplopanax horridus).  Chinese rice paper from the pith of Tetrapanax papyriferus. Note that Hedera spp have become a widespread invasive species in many areas and should only be used with extreme caution.

Morphology of Araliaceae in North America

Araliaceae Species I have Covered So Far

Aralioideae Subfamily

Aralia nudicaulis – Wild Sarsaparilla

Herbaceous perennial from underground stems. Large compound leaves have 5 (3 – 7) finely serrated leaflets, often purplish-green. Small white flowers in rounded clusters 4 – 5 cm wide on scapes not much taller than the leaves. Flowers are followed by edible purple-black berries. Native to northern and eastern North America.

Aralia spinosa – Devil’s Walking Stick

Aromatic spiny deciduous shrub or small tree 2 – 8 m tall with exceptionally large bipinnate leaves 70 – 120 cm long. Small white flowers in compound panicles are followed by purplish-black berries. Native to eastern North America.

Fatsia japonica – Paperplant

Evergreen shrub with stout, sparsely branched stems. Large 20 – 40 cm deeply palmately lobed leaves have 7 – 9 lobes, are spirally arranged, leathery and on long petioles. Flowers are small, white, borned in dense terminal compound umbels followed by small black berries. Native to Japan and Korea, cultivated in North America.

Hedera helix – English Ivy

A highly invasive vigorous root-climbing vine with variably 3 – 5 lobed leaves, depending on the cultivar and if it has reached reproductive age. It seldom flowers but produces small umbels of greenish-yellow flowers followed by purple-black berries. It spreads mostly vegetatively and takes over entire areas when it is left unchecked. Click for more information!

Oplopanax horridus – Devil’s Club

Woody deciduous spiny perennial shrub with large spiny palmately lobed leaves, small yellow-green flowers in racemes followed by clusters of small red berry-like drupes. Endemic to North America, mostly the Pacific Northwest, with a small disjunct population in the Great Lakes. Click the link for more info!

Taxonomy of Araliaceae

1513 spp in 44 genera of the Apiales order of the core Eudicots (dicots). Currently, there are two recognized subfamilies in the Araliaceae. 

1. Aralioideae – The largest subfamily is made mostly of shrubs and trees, sometimes herbs or root or stem climbers. Leaves are usually pinnately to palmately compound, stipulate with connate, intrapetiolar, hooded, or sometimes cauline stipules. Fruit is almost always a drupe.  
2. Hydrocotyloideae – Herbaceous perennials, sometimes annuals and some aquatics, the stem has endodermis. Leaf lamina is orbicular–peltate or deeply twice lobed palmately, the margin is crenate or serrate, and they are stipulate cauline or petiolar. 

Genera:

Aralioideae: Anakasia (1), Aralia (73 inc Hunaniopanax, Megalopanax, Pentapanax), Astropanax (15), Astrotricha (20), Brassaiopsis (45), Cephalaralia (1), Cheirodendron (6), Chengiopanax (2), Crepinella (1), Cussonia (20), Dendropanax (91), Didymopanax (16), Eleutherococcus (29), Fatsia (3 inc Boninofatsia), Gamblea (4), Harmsiopanax (3), Hedera (18), Heptapleurum (63), Heteropanax (9), Kalopanax (1), Macropanax (18 inc Cromapanax), Merrilliopanax (3), Meryta (29), Metapanax (2), Motherwellia (1), Neocussonia (16), Neopanax (5), Oplopanax (3), Oreopanax (147), Osmoxylon (61), Panax (13), Plerandra (33), Polyscias (173 inc Arthrophyllum, Cuphocarpus, Gastonia, Munroiodendron, Reynoldsia, Tetraplasandra), Pseudopanax (7), Raukaua (6), Schefflera (309), Sciodaphyllum (21), Seemannaralia (1), Sinopanax (1), Tetrapanax (1), Trevesia (8), Woodburnia (1). Hydrocotyloideae: Hydrocotyle (173 inc Neosciadium), Trachymene (60 inc Uldinia).

Key Differences From Similar Families

The Araliaceae and Apiaceae are both similar to and closely related to each other and often the two can be hard to differentiate. However, some more common differences include the fact that the Apiaceae are usually herbs vs usually shrubs and trees in the Araliaceae, the leaves that usually lack stipules in Apiaceae vs usually present in Araliaceae, and the fruit being a dry schizocarp with two mericarps vs a berry-like drupe in the Araliaceae.

Distribution of Araliaceae

Araliaceae is mostly a tropical family, but some are endemic to temperate climates as well. They are in Eurasia, Africa, Australia, New Zealand, New Caledonia, Pacific islands, and the Americas from Arctic Canada to temperate South America.

Distribution of Araliaceae in the Americas

Canadian Genera Include:

Aralioideae:Aralia 5 of 73 Americas & Asia spp native all of Canada exc NU; Eleutherococcus 1 of 29 E Asian spp intro ON; Hedera 1 of 18 mostly Eurasian spp intro BC, ON, very invasive where it has escaped; Kalopanax monospecific E Asia sp intro ON; Oplopanax 1 of 3 Americas & E Asia spp native BC, AB, YT, ON; Panax 2 of 13 E Asia & NAM spp native ON, QC, NB, NS, PE, most of the genus endemic to Asia. Hydrocotyloideae: Hydrocotyle 4 of 173 cosmopolitan spp native ON, QC, NB, NS, PE, NL (exc Labrador), intro BC.

USA Genera Include:

Aralia 8 of 73 Americas & Asia spp native and intro all of USA exc NV; Cheirodendron 5 of 6 C Pacific endemic spp endemic to HI; Eleutherococcus 1 of 29 E Asian spp intro UT, IN, KY, OH, WV, PA, NY, CT, MA; Hedera 3 of 18 mostly Eurasian spp intro most of USA EXC NV, MT S to NM, ND S to OK, MN, IA, WI, VT, NH, ME and inc HI, very invasive where it has escaped; Heptapleurum ? of 63 S & Tropical Asia spp intro FL and HI; Kalopanax 1 monospecific E Asia sp intro NY, CT, MD, VA, OH, IN; Oplopanax 1 of 3 Americas & E Asia spp native WA, OR, ID, WY, MI, NY, AK; Panax 2 of 13 E Asia spp native all E USA ND S to TX and all E exc ND, TX, FL, most of the genus endemic to E Asia; Polyscias 10 of 173 Old World Tropics & Pacific spp inc 9 spp native/endemic HI (sometimes as Munroiodendron, Reynoldsia, Tetraplasandra) and 1 sp intro FL; Schefflera 2 of 309 pantropical spp (exc Africa) native and intro FL, native HI; Tetrapanax monospecific S China sp intro AL, FL and HI. Hydrocotyloideae: Hydrocotyle 9 of 173 cosmopolitan spp native and intro most USA exc ID, MT, WY, CO, ND, SD, NE, IA and intro HI.     

Mexico Genera Include:

Aralioideae: Aralia ?? of 73 Americas & Asia spp native all of Mexico; Dendropanax ?? of 91 Americas & Tropical & E Asia spp native moist forests at lowland to mid-elevation areas most of Mexico exc BC, BCS, Son, Sin; Didymopanax 1 of 16 Mexico & Neo endemic spp native SW+SE Mexico, Ver; Oreopanax ?? of 147 Mexico & Neo endemic spp native throughout Mexico inc Mexican Pacific Is. Hydrocotyloideae: Hydrocotyle ?? of 173 cosmopolitan spp native throughout all of Mexico.

Neotropical Genera Include:

Aralioideae: Aralia ?? of 73 Americas & Asia spp native CAM, Cuba, Hispaniola, Colombia, Venezuela, Peru, Bolivia, Paraguay, N Argentina, E+S Brazil, most in seasonally dry forests below 500m; Crepinella monospecific SAM endemic sp of Colombia, Venezuela, Guyana, N+C Brazil, Ecuador, Peru; Dendropanax ?? of 91 Americas & Tropical & E Asia spp native moist forests at low to mid-elevation areas up to around 1500m in CAM, Greater Antilles, Leeward Is, Venezuelan Antilles, Trinidad-Tobago, tropical SAM S to Peru, Bolivia, NE Argentina (exc Suriname, French Guiana, Uruguay); Didymopanax 16 of 16 spp Mexico & Neo endemic spp native CAM, Cuba, Hispaniola, Puerto Rico, Leeward Is, Trinidad-Tobago, tropical SAM S to NE Argentina (exc NW Argentina, N Chile), inc 12 narrow endemics of Brazil; Fatsia 1 of 3 Japan, Korea & Taiwan spp intro Juan Fernandez Is; Heptapleurum ?? of 63 S & Tropical Asia spp intro Bermuda, Bahamas, Hispaniola, Jamaica, Puerto Rico, Leeward & Windward Is; Oreopanax 147 of 147 Mexico & Neo endemic spp, mostly in mountains in the tropics above 1500m in CAM, Antilles (exc Cayman Is, Aruba, Netherlands Antilles), Trinidad-Tobago, Colombia, Venezuela, Guyana, Suriname?, French Guiana, N+E+S Brazil, Ecuador, Peru, Bolivia, NW Argentina; Plerandra 1 of 33 S Pacific Is spp intro Trinidad-Tobago; Polyscias ?? of 173 Old World Tropics & Pacific spp intro El Salvador, Bahamas, Hispaniola, Leeward Is, Puerto Rico, Trinidad-Tobago, Venezuelan Antilles; Raukaua 2 of 6 temperate S Hemisphere spp endemic to N+C Chile + S Argentina (1), C Chile (1); Schefflera ?? of 309 pantropical spp (exc Africa) native in moist habitats at mid to high elevations up to 3000 m in Costa Rica, Panama, tropical SAM S to Peru, Bolivia, C+S Brazil, Hispaniola, Jamaica, Leeward & Windward Is, intro Bahamas, Bermuda; Sciodaphyllum 21 of 21 Neo endemic spp of Jamaica, Nicaragua, Costa Rica, Panama, Colombia, Ecuador, Peru, Bolivia, Venezuela; Tetrapanax  monospecific S China sp intro S Brazil. Hydrocotyloideae: Hydrocotyle ?? of 173 cosmopolitan spp widespread in moist habitats of CAM, Bermuda, Bahamas, Cuba, Hispaniola, Jamaica, Puerto Rico, Leeward & Windward Is, Galapagos, and all of SAM, with high diversity in the Andes.

Patagonia Genera Include:

Aralioideae: Raukaua 2 of 6 temperate S Hemisphere spp endemic to N+C Chile + S Argentina (1), C Chile (1). Hydrocotyloideae: Hydrocotyle ? of 173 cosmopolitan spp native Patagonia inc Falkland Is.

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. Orchids, 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