Araliaceae

The Araliaceae are a diverse family of flowering plants comprising approximately forty-three genera and around 1,500 species. Commonly referred to as the ginseng family, they include predominantly woody taxa alongside several herbaceous representatives. Members of the family are distributed across tropical and temperate regions worldwide, with notable centres of diversity in Southeast Asia, the Pacific and the Americas. Many species possess considerable cultural, economic and horticultural value, ranging from ornamental foliage plants to medicinal herbs such as Panax ginseng.

Morphological Characteristics

Araliaceae exhibit substantial morphological variation, and for this reason no single diagnostic character reliably defines the family. Nevertheless, several traits commonly occur among its members. Plants are generally characterised by a woody habit, the frequent presence of aromatic oils, large alternate leaves, and umbel-like inflorescences. The flowers typically bear five petals and two to five carpels, while the fruits are usually berries lacking oil cavities. In some species, the stems or leaves may carry prickles, and although the family is primarily woody, herbaceous forms also exist.
Leaves may be simple or compound; where compound, they are often ternate, pinnate or palmate. Some species possess lauroid foliage, with leaves resembling those of Laurus. Ecologically, Araliaceae occur in a range of humid habitats, including pluvial montane forests, cloud forests, laurel forests and lowland riverine systems. Their global distribution spans the Americas, Eurasia, Africa, Australasia and numerous Pacific islands.
Several members are well known. Examples include Aralia spinosa (angelica tree), Oplopanax horridus (devil’s club), Hedera helix (common ivy) and medicinal species of Panax. Ornamental plants such as Hedera, Fatsia and Heptapleurum are widely cultivated for foliage and landscape use.

Taxonomy and Systematics

Within the APG IV classification of flowering plants, Araliaceae form one of six recognised families of the Apiales, an order within the asterid clade. Molecular evidence supports the monophyletic status of Araliaceae, although the internal relationships are complex. Four major groups are generally recognised:

1. Greater Raukaua group, sister to the remaining main lineages of the family.
2. Aralia–Panax group, encompassing the mostly monophyletic genera Aralia and Panax.
3. Polyscias–Pseudopanax group, sister to Cussonia and the Asian Palmate assemblage.
4. Asian Palmate group, the largest and taxonomically most diverse lineage within Araliaceae.

Despite these broad groupings, numerous genera do not fall neatly within them, reflecting ongoing instability and revision at the generic level. Historically, many taxa were placed within a very broad concept of Schefflera, a pantropical genus formerly thought to contain roughly half the species in the family. Molecular phylogenies have since demonstrated that this large genus is polyphyletic, prompting recommendations for its division into more natural units. These revised groupings do not necessarily correspond to earlier taxonomic treatments, illustrating the need for continued systematic study.
The systematics of Araliaceae have long been challenging, partly due to the highly variable morphological characters and partly due to outdated reliance on superficial similarities. In earlier classifications, Araliaceae were sometimes merged with the closely related Apiaceae (Umbelliferae), but molecular evidence now supports their separation. Nevertheless, the family retains close affinities with both Apiaceae and Pittosporaceae, and the precise boundaries among these families continue to receive scientific attention.
A particularly problematic group for classification has been the traditional Hydrocotyloideae, which historically spanned taxa placed in both Araliaceae and Apiaceae. Molecular studies suggest that only the genera Hydrocotyle, Trachymene and Harmsiopanax should be retained in this subfamily to ensure monophyly.

Subfamilies and Genera

The currently recognised subfamilial structure includes the following groups:
Subfamily AralioideaeAnakasia, Aralia, Astropanax, Astrotricha, Brassaiopsis, Cephalaralia, Cephalopanax, Cheirodendron, Chengiopanax, Crepinella, Cussonia, Dendropanax, Didymopanax, Eleutherococcus, Fatsia, Frodinia, Gamblea, Harmsiopanax, Hedera, Heptapleurum, Heteropanax, Kalopanax, Macropanax, Megalopanax, Merrilliopanax, Meryta, Metapanax, Motherwellia, Neocussonia, Neopanax, Oplopanax, Oreopanax, Osmoxylon, Panax, Paleopanax, Plerandra, Polyscias, Pseudopanax, Raukaua, Schefflera, Sciadodendron, Sciodaphyllum, Seemannaralia, Sinopanax, Tetrapanax, Trevesia, Woodburnia.
Subfamily HydrocotyloideaeHydrocotyle, Trachymene.
Subfamily incertae sedisAraliaceoipollenites (fossil pollen).

Economic and Cultural Importance

Several genera within Araliaceae are valued for ornamental horticulture, particularly species of Hedera, Fatsia, Heptapleurum and Plerandra, which are frequently cultivated as indoor foliage plants or landscape ornamentals. Panax ginseng and related species have long been used in traditional medicine, especially in East Asia, where their roots are employed as tonic and adaptogenic remedies.
The family’s ecological significance lies in its role within humid and montane forest ecosystems, where many species contribute to canopy and understory structure, provide food resources for wildlife and exhibit high levels of endemism in certain regions.