Each tree bears either male or female flowers, never both. This tree is festooned with long drooping male flowers.
Male flowers look like narrow cone-shaped spikes that face up when young. As the male spikes bloom, they elongate into longer spikes (5-10cm).
Eventually drooping down in long yellow tassels.This tree bears female flowers, many of which have already become green fruits.The female flower forms on shorter cone-shaped spikes. According to Tomlinson the flowers are pollinated by insects as the pollen is sticky. Bees are common visitors and may be the chief pollinators.The fruits are small (less than 1cm) green turning black as they ripen into dry capsules. Each capsule is made up of three portions, containing tiny black seeds.
The small shapely leaves are oval and pointed (5-10cm), thick and green, arranged in a spiral. Young leaves are pink, old leaves turn yellow then red before dropping off. Leaves usually drop off after dry weather.
Buta-buta or Blind-your-eye (Excoecaria agallocha) gets its common name from the milky sap or latex that oozes out of broken leaves, bark and twigs. This sap is poisonous and can blister skin, hurt eyes and may even cause blindness. 'Buta' means 'blind' in Malay.
Corners recorded them as "locally common, as in Kranji Forest Reserve by the main road" where "they give a beautiful display of red and yellow autumn tints" ostensibly when the leaves fall during dry weather. According to Giesen, it requires freshwater input for a large part of the year and is commonly found on the landward margin of mangroves, on beach swales or occasionally above the high tide mark.
According to Burkill, the timber is much used in some places for firewood and to make small articles. But it is tricky to cut down the tree as the spattering of the milky sap can blister bare skin and cause eye damage. Experienced wood cutters first remove the bark before felling the tree. The latex is used as a fish poison as well as in dart poison. Various traditional medicinal uses are made of the bark, leaves and roots. According to Wee, the plant contains behenic acid. The Burmese used the leaves to treat epilepsy, in the Solomon Islands the latex is taken with coconut milk as a powerful purgative and an emetic, and oil distilled from the wood is used by the Malays to treat itching and skin infections. According to Giesen, it is not used as firewood as it produces an unpleasant smoke. But the wood is used to make matchsticks in the Philippines, also sold as aromatic wood, and is considered useful for carving. The roots are used to treat toothache and swellings.
- Buta-buta (Excoecaria agallocha) Ng, Peter K. L. & N. Sivasothi, 1999. A Guide to the Mangroves of Singapore I (Plant Diversity). Singapore Science Centre. 168 pp.
- Giesen, Wim and Stephan Wulffraat, Max Zieren and Liesbeth Scholten. 2006. Mangrove Guidebook for Southeast Asia (PDF online downloadable). RAP publication 2006/07 Food and Agriculture Organization of the United Nations Regional Office for Asia and the Pacific Bangkok.
- Hsuan Keng, S.C. Chin and H. T. W. Tan. 1990, The Concise Flora of Singapore: Gymnosperms and Dicotyledons. Singapore University Press. 222 pp.
- Corners, E. J. H., 1997. Wayside Trees of Malaya: in two volumes. Fourth edition, Malayan Nature Society, Kuala Lumpur. Volume 1: 1-476 pp, plates 1-38; volume 2: 477-861 pp., plates 139-236.
- Tomlinson, P. B., 1986. The Botany of Mangroves. Cambridge University Press. USA. 419 pp.
- Burkill, I. H., 1993. A Dictionary of the Economic Products of the Malay Peninsula. 3rd printing. Publication Unit, Ministry of Agriculture, Malaysia, Kuala Lumpur. Volume 1: 1-1240; volume 2: 1241-2444.
- Wee Yeow Chin. 1992. A Guide to Medicinal Plants. The Singapore Science Centre. 160pp.