Antiaris is a monotypic genus in the mulberry and fig family Moraceae, order Rosales, containing a single species, Antiaris toxicaria. The genus was historically treated as several species, but is now regarded as one highly variable species divisible into approximately five subspecies. A notable morphological gradient exists within the species: fruit size decreases progressively from Africa toward Polynesia.
The genus has a remarkably wide distribution in tropical regions, occurring across tropical Africa, tropical Asia, Australia, Indonesia, the Philippines, Tonga, and various other Pacific islands. Seeds are dispersed by birds, bats, possums, monkeys, deer, antelopes, and humans. Trees are found in grassy savanna, coastal plateaus, and wet forests including rainforest, riverine forest, and semi-swamp forest, generally below 1500 metres elevation.
Antiaris toxicaria produces a latex containing intensely toxic cardenolides, most notably the cardiac glycoside antiarin. This toxin has been used for centuries in Island Southeast Asian cultures — including ethnic groups in the Philippines, Borneo, Sulawesi, and Malaysia — to poison darts for sumpit blowguns used in hunting and warfare. The concentrated sap is known under various regional names including upas, apo, and ipoh. This association with deadly poison gave rise to legendary accounts, most famously a 1783 account in The London Magazine claiming the tree could destroy all animal life within 15 miles, an exaggeration later traced to a nearby toxic volcanic valley rather than the tree itself.
The tree also has economic significance: it yields lightweight hardwood (density 250–540 kg/m³) valued for veneer, bark high in tannins used for dyeing and paints, and bast fibre harvested in Africa and Polynesia for making strong bark cloth. It grows quickly and is cultivated as a shade tree near human dwellings; its leaf litter serves as compost and green manure.
Etymology
The genus name Antiaris is derived directly from the Javanese word ancar (rendered in obsolete Dutch-era spelling as antjar), the local name for the tree. In Javanese tradition the tree is also known as upas, meaning "poison" — a word that entered English as "upas tree." Other common names include bark cloth tree, false iroko, and false mvule.
Distribution
Antiaris has a pantropical distribution spanning tropical Africa, tropical Asia, Australia, Indonesia, the Philippines, Tonga, and other Pacific islands. In Africa three distinct habitat varieties are recognised: one restricted to wooded grassland and two found in wet forests (rainforest, riverine forest, and semi-swamp forest). The genus generally does not occur above 1500 metres elevation, and it is uncertain how many island populations represent natural range versus dispersal facilitated by birds and bats.
Cultural Uses
The latex of Antiaris toxicaria has been used as an arrow and dart poison for centuries across Island Southeast Asia, where the concentrated sap — known as upas, apo, or ipoh — is applied to blowgun darts for hunting and warfare in the Philippines, Borneo, Sulawesi, and Malaysia. In Javanese tradition it is mixed with Strychnos ignatii to create arrow poison. In Hainan, China, the Li people smeared the latex onto arrowheads; the tree is called "Arrow Poison Wood" (箭毒木). Separately, in Africa and Polynesia the bast fibre is harvested to make strong bark cloth for clothing, often decorated with dye derived from the bark's tannins.
History
The upas tree acquired an outsized legendary reputation in European literature after a 1783 account in The London Magazine, attributed to one Foersch (a surgeon at Semarang in 1773) and later popularized by Erasmus Darwin, claimed the tree killed all animal life within 15 miles. Geoffrey Grigson proposed the exaggerated account was perpetrated by George Steevens; the actual deaths were attributed to toxic gases from an adjacent extinct volcano near Batar. Despite this correction, literary allusions persisted: Pushkin wrote a poem on the Upas-Tree, George Eliot used it as a metaphor in her essay on "Silly Novels by Lady Novelists," and Thomas Mann referenced it in The Magic Mountain (1924).
