Lee Kong Chian Natural History Museum

Excoecaria agallocha Linnaeus

Kingdom:Plantae
Phylum/Division:Magnoliophyta
Class:Eudicots
Order:Malpighiales
Family:Euphorbiaceae
Genus:Excoecaria
Species:E. agallocha
Common Names:Buta-buta, Blind-your-eyes
Status:Common

Etymology

The genus name Excoecaria is derived from the Latin word ex-caecare which means 'to make blind'. Its Malay name of 'Buta-buta' also reflects this, meaning 'blind'.

Description

This is a small evergreen or deciduous tree that grows to 15 m tall with young leaves that are pink and old leaves that turn scarlet. Leaves are simple, 2.5-11 x 2-6 cm, elliptic and down-pointing with upcurled sides. It is dioecious, with male and female flowers borne on different trees. Flowers are arranged in a catkin-like inflorescence. Male inflorescences are in 5-10 cm long while female inflorescences, if shorter, at 1.2-4 cm long.  Among local mangrove plants, the drooping flowering shoot is a unique characteristic. Fruits are 3-shouldered capsules, about 7 mm wide, resembling a miniature rubber fruit.

Read more about the Malpighiales order.
Read more about the Euphorbiaceae family.

Distribution

From tropical Africa to Australia.

Localities

Admiralty Park, Khatib Bongsu, Lim Chu Kang, Mandai Mangrove, Pasir Ris Park, Pulau Semakau, Pulau Tekong, Pulau Ubin, St John's Island, Sungei Buloh Wetland Reserve

Locality Map

General Biology

Like other mangrove plants, Buta-buta is adapted to cope with high salinity levels. It is able to exclude 80-90% of the salt absorbed during the uptake of brackish water. The remaining amount of salt is accumulated in older leaves that are shed seasonally.

The tree is commonly pollinated by bees, which are attracted by the sticky nectar exuded from the glands at the margins of the bracts that are associated with the flowers of the inflorescence.

The white latex of Buta-buta is poisonous, and can cause blisters and/or blindness if contacted.

Ecological Role

It is a host plant of the Mangrove Longhorn Beetle (Aeolesthes holosericeus) larvae, which drill discs into the trunks of dead or sick individuals.

Human Uses

In traditional medicine, the leaves are used to treat urticaria and herpes zoster as well as to arrest bleeding. The poisonous latex has a variety of uses including the treatment of ulcers, as a fish poison for catching fish, and for poison darts. The roots are pounded with ginger to reduce swellings on hands and feet. It is also used as an abortifacient in New Guinea.

References

Chong, K. Y., H. T. W. Tan & R. T. Corlett, 2009. A Checklist of the Total Vascular Plant Flora of Singapore: Native, Naturalised and Cultivated Species. Raffles Museum of Biodiversity Research, National University of Singapore, Singapore. 273 pp.

Ng, P. K. L., L. K. Wang & K. K. P. Lim (eds.), 2008. Private Lives: an Exposé of Singapore's Mangroves. The Raffles Museum of Biodiversity Research, Singapore. 249 pp.

van Valkenburg, J.L.C.H. & N. Bunyapraphatsara (eds.) 2002. Plant resources of South-East Asia No. 12(2). Medicinal and poisonous plants 2. Prosea Foundation, Bogor, Indonesia. 782 pp.

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