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Semecarpus australiensis – Wikipedia

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– Tar tree is a large rainforest tree up to 40m (130ft) in height.
– Trunk is generally straight and cylindrical with oval-shaped lenticels.
– Leaves are up to 30cm (12in) long and 12cm (4.7in) wide with pale yellow veins.
– Flowers are pentamerous, with small petals on male flowers and larger on female flowers.
– Fruits are true nuts attached beneath a colorful fleshy receptacle.

– Semecarpus australiensis was first described by Adolf Engler in 1883.
– Description published in volume 4 of Monographiae Phanerogamarum.
Genus name Semecarpus is from Latin “semi-” meaning half and Greek “κᾰρπός” meaning fruit.
– Species epithet means from Australia.

Distribution and habitat:
– Natural range includes Moluccas, New Guinea, Vanuatu, and parts of Australia.
– Grows in lowland rainforest, monsoon forest, and gallery forest.
– Found close to the sea or watercourses.
– Distribution extends from the west to the east and south.

– Fruits are eaten by cassowaries without adverse effects.
– Serves as a host plant for larvae of the Purple Line-blue butterfly.
– Cassowaries consume the fruits without issues from the toxic sap.
– Butterfly larvae feed on the tree during their development.
– Plays a role in the ecosystem by providing food for wildlife.

Tree can cause severe allergic responses due to resinous phenolic compounds.
– Allergens are present in most parts of the plant, including fruits and exudate.
– Direct contact with the tree is not necessary for allergic responses.
– Historical incidents have shown allergic reactions from swimming near the tree.
– Allergic reactions can occur without direct physical contact.

Indigenous uses:
– Indigenous Australians knew about the plant’s toxic nature and kept children away.
– They found ways to deactivate toxins in the fleshy receptacle and nut for consumption.
– Methods included covering hands with clay and roasting nuts before consumption.
– Smoke from the fire used for roasting could also cause issues.
– Indigenous people were cautious in handling and preparing parts of the tree for consumption.

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