Elateriospermum is a monotypic genus of flowering plant in the spurge family, Euphorbiaceae (order Malpighiales), described by Carl Ludwig Blume in 1826. It is the sole member of tribe Elateriospermeae and contains a single living species, Elateriospermum tapos, known locally as buah perah or the perah tree. Two other names once described in the genus — E. paucinervium and E. tokbrai — have since been reclassified as synonyms of Blumeodendron tokbrai, leaving E. tapos as the genus's only current representative.
The tree is native to Southeast Asia, ranging through southern Thailand, Peninsular Malaysia, Borneo, Java, and Sumatra. It grows up to 27 m tall, occasionally reaching 50 m, with a bole as tall as 10 m that is sometimes fluted or buttressed. It favors hilly primary (mixed dipterocarp) and secondary forest, kerangas (heath) forest, forest edges, and logging roads from sea level to about 600 m elevation, typically on deep clay or sandy-clay soils.
The species has notable economic and cultural significance across its range. Its seeds are commonly sold in local markets and eaten roasted or boiled, but the raw seed contains cyanogenic compounds and is poisonous unless thoroughly cooked; a fermented seed paste is also used to flavour sambal. The tree's latex is applied to wounds for its quick-drying properties and is used to polish blowpipes, while its durable but termite-prone heartwood is worked into small items such as rubber-tapping-knife handles and used as fuel. The plant also carries a place in Thai literature and local folklore, including a tradition that burning its wood produces little smoke, useful for concealment during conflict.
Distribution
Native to Southeast Asia, found in southern Thailand, Peninsular Malaysia, Borneo, Java, and Sumatra, growing in lowland to hill forests up to about 600 m elevation.
Ecology
Grows in hilly primary (mixed dipterocarp) and secondary forest, kerangas (heath) forest, forest edges, and along logging roads from sea level to roughly 600 m, typically on deep clay, clay-loam, sandy-clay, or loamy soils, sometimes sandstone or laterite.
Cultivation
Not cultivated commercially — cultivation status is wild. It is a plant of the hot, humid lowland tropics and flowers and fruits throughout the year.
Cultural Uses
The seed (buah perah) is sold in local markets and eaten roasted or boiled; the raw seed contains cyanogenic compounds and is poisonous unless thoroughly cooked. A pounded seed paste flavours sambal and is sometimes fermented for a month or more in a bag or bamboo buried in wet earth. Latex is used medicinally on wounds and cracked feet and to polish blowpipes; the durable but termite-prone wood is used for small carved items and fuel. Seeds also serve as children's toys and in a game called "conquerors." The plant is referenced in Thai literature and in folklore describing its wood as producing little smoke when burned, useful for concealment during conflict.
Taxonomy Notes
Elateriospermum is monotypic and the sole genus in tribe Elateriospermeae. Two names once placed in the genus, E. paucinervium Elmer and E. tokbrai Blume, are now treated as synonyms of Blumeodendron tokbrai, leaving E. tapos as its only current species — consistent with GBIF's record of a single descendant.
