Excoecaria agallocha L., Fake Agarwood

Taxonomy

Kingdom: Plantae – Plants
Phylum: Magnoliophyta – Flowering Plants
Class: Magnoliopsida – Dicotyledons
Order: Malpighiales
Family: Axioidea
Subfamily: Euphorbioideae
Tribe: Hippomaneae
Genus: Excoecaria
Specific epithet: agallocha – Linnaeus, C. von (1759) Systema Naturae ed. 10: 1288. Type: Tropical Asia, Malaya & Pacific Islands.
Botanical name: – Excoecaria agallocha L.

Common name

Mangrove, Blind Your Eye; Blind Your Eye; Blind Your Eye Mangrove; Blind-your-eyes-tree; Milky Mangrove; Blinding Tree; Mangrove, Milky; River Poisonous Tree; Scrub Poison Tree, Palétuvier aveuglant, Buta-Buta.

Habitat

Mangrove and tidal forests , brackish areas and rice fields ; sea level to 100 m. Typically found in the intertidal zone at the water’s edge at a mean distance from sea level of -365 meters (-1,197 feet). The tree grows further inland usually at the high water mark. It can grow in both stony and muddy ground. The tree can tolerate dry and salty conditions. It grows quickly in open areas, but can also survive in shade.

Uses

Natives in New Guinea use the sap as an ingredient in arrow poison. The sap is also used to stun fish. The timber is soft, white, light with a fine grain and rots quickly. Nevertheless, in Bangladesh, the tree is an important source of cheap planks, matches and matchboxes, and pulp for paper. The timber is easily transported by water as it floats. It is also used as firewood and converted into charcoal.

Traditional medicinal uses: The plant is used to treat sores and stings from marine creatures. Smoke from the bark is used to treat leprosy. The plant is being tested for modern medical uses. Modern clinical trials show that the plant may have anti-HIV, anti-cancer, anti-bacterial and anti-viral properties.

Unambiguous Synonyms

1. Commia cochinchinensis Lour.
2. Commia cochinchinensis Loureiro.
3. Excoecaria affinis Endl.
4. Excoecaria agallocha var. camettia (Willd.) Müll. Arg.
5. Excoecaria agallocha var. genuina Müll. Arg.
6. Excoecaria agallocha var. lancifolia Pax & K. Hoffm.
7. Excoecaria agallocha var. orthostichalis Müll. Arg.
8. Excoecaria agallocha var. ovalis (Endl.) Müll. Arg.
9. Excoecaria camettia Willd.
10. Excoecaria ovalis Endl.
11. Excoecaria sphaerosperma F. Muell. Ex Pax
12. Stillingia agallocha (L.) Baill.

Members of the genus Excoecaria

E. acerifolia · E. acuminata · E. agallacha · E. agallocha · E. albicans · E. antsingyensis · E. aporusifolia · E. bantamensis · E. benthamiana · E. biglandulosa · E. borneensis · E. bussei · E. canjoerensis · E. cochichinensis · E. cochinchinensis (Chinese Croton) · E. cochinchinensis ‘Firestorm’ (Chinese Croton) · E. conchinchensis · E. confertiflora · E. dallachyana · E. diandra · E. formosana · E. formosana var. daitoinsularis · E. formosana var. formosana · E. gigantea · E. glaucescens · E. goudotiana · E. grahami · E. grahamii · E. guineensis · E. guinensis · E. herbertiifolia · E. holophylla · E. humbertii · E. ilicifolia · E. indica · E. integrifolia · E. kawakamii · E. laevis · E. laotica · E. lissophylla · E. madagascariensis · E. magenjensis · E. myrioneura · E. obtusa · E. oppositifolia · E. oppositifolia var. crenulata · E. oppositifolia var. oppositifolia · E. orientalis · E. ovatifolia · E. pachyphylla · E. pallens · E. parvifolia · E. perrieri · E. philippinensis · E. poilanei · E. polyandra · E. rectinervis · E. riparia · E. robusta · E. simii · E. stenophylla · E. terminalis · E. thouarsiana · E. venenata · E. yunnanensis

Distribution

In South Asia this species is found in Bangladesh, Brunei Darussalam, China, Taiwan, Hong Kong, India, Indonesia, Japan, Malaysia, Myanmar, Philippines, Singapore, Sri Lanka, Thailand, Viet Nam. The species also occurs in the Maldives.

In Australasia it can be found in Northwest Australia, Northeast Australia, Southeast Australia, Federated States of Micronesia, Fiji, Guam, New Caledonia, Palau, Papua New Guinea, Solomon Islands, Tonga, Vanuatu.

Details: Akurala, Ao Sawi, Bais, Balapitiya, Bangladeshi Exclusive Economic Zone, Bentota Ganga, Brunei darussalam, Calliope River, Chinese Exclusive Economic Zone, Devinuwara Lagoon, Dickwella, East India, Fijian Exclusive Economic Zone, Galle-Unawatuna, Garanduwa Lagoon, Gin Oya, Ginganga, Godavari Estuary, Goiyyapana, Hikkaduwa, Hinchinbrook Channel, Hong Kong, Indonesian Exclusive Economic Zone, Japanese Exclusive Economic Zone, Kakinada Bay, Kalametiya, Kaluwamodara, Kataketiya, Kemaman District, Kirama Oya Mouth, Kosgoda, Lunama, Madampa Ganga, Mahanadi Delta, Mai Po Marshes, Malaysian Exclusive Economic Zone, Maldives Exclusive Economic Zone, Manko Wetland, Mawella Lagoon, Micronesian Exclusive Economic Zone, Mundel, Myanmar Exclusive Economic Zone, Negombo Lagoon, New Caledonian Exclusive Economic Zone, Nilwala Ganga, Normanby River, North East Australia, North West Australia, Northern Marianes and Guam Exclusive Economic Zone, Pak Phanang, Palau Exclusive Economic Zone, Pambala-Chilaw, Pangaimotu, Papua New Guinean Exclusive Economic Zone, Philippines Exclusive Economic Zone, Pichavaram, Polwatumodara, Puttalam Lagoon, Ranong Biosphere Reserve, Ratgama Oya, Rekawa, Rongat Bay, Seenimodara canal mouth, Sematan, Singaporean Exclusive Economic Zone, Solomon Islands Exclusive Economic Zone, South East Australia, Sri Lankan Exclusive Economic Zone, Suduwella, Sundarbans, Taiwanese Exclusive Economic Zone, Talalla, Thailand Exclusive Economic Zone, Tillawatawana, Tondilay Lagoon, Tongan Exclusive Economic Zone, Trat Bay, Vanuatu Exclusive Economic Zone, Vietnamese Exclusive Economic Zone, Walawey Ganga, West India.

Major Threats

Sea level rise is a major threat, especially to back mangroves that have no area in which to expand. Mangrove species with a habitat on the landward margin may be particularly vulnerable to sea-level rise if owing to coastal development their movement inland is blocked. Howevever, species that are easily dispersed and fast growing/ fast producing will cope better than those which are slower growing and slower to reproduce. Although local estimates are uncertain due to differing legislative definitions of what is a ‘mangrove’ and to the imprecision in determining mangrove area, current consensus estimates of mangrove loss in the last quarter-century report an approximately 21% decline in mangrove areas in countries within this species range since 1980 (FAO 2007).

All mangrove ecosystems occur within mean sea level and high tidal elevations, and have distinct species zonations that are controlled by the elevation of the substrate relative to mean sea level. This is because of associated variation in frequency of elevation, salinity and wave action (Duke et al. 1998). With rise in sea-level, the habitat requirements of each species will be disrupted, and species zones will suffer mortality at their present locations and re-establish at higher elevations in areas that were previously landward zones (Ellison 2005). If sea-level rise is a continued trend over this century, then there will be continued mortality and re-establishment of species zones.

In addition, mangrove area is declining globally due to a number of localized threats. The main threat is habitat destruction and removal of mangrove areas. Reasons for removal include cleared for shrimp farms, agriculture, fish ponds, rice production and salt pans, and for the development of urban and industrial areas, road construction, coconut plantations, ports, airports, and tourist resorts. Other threats include pollution from sewage effluents, solid wastes, siltation, oil, and agricultural and urban runoff. Climate change is also thought to be a threat, particularly at the edges of a species range. Natural threats include cyclones, hurricane and tsunamis.

See also:

• Anti-ulcer Activity of Excoecaria agallocha bark (PDF)
• Excoecaria Agallocha L. Antimicrobial Properties Against Important Pathogenic Microorganisms (PDF)
• Phytochemical Screening and Antimicrobial Assessment of Leaf Extracts of Excoecaria Agallocha L. (PDF)
• Screening of Antioxidant and Antifilarial Activity of leaf extracts of Excoecaria agallocha L. (PDF)
• Characterization of cytotoxic compound from mangrove derived fungi Irpex hydnoides VB4 (PDF)
• Medicinal Plants in Papua New Guinea (PDF)
• Bioactivity of Excoecaria agallocha · External Link
• Excoecaria agallocha – Encyclopedia of Life · External Link
• Pentingnya Pelestarian “Hutan Mangrove” Untuk Mengatasi Perubahan Iklim · External Link

Excoecaria agallocha (Buta-Buta or Blind-Your-Eye) Brief Info

Where seen? This tree with small neat leaves can be spectacular when in male flower bloom, or when the leaves turn red before dropping off. They are quite commonly seen on Singapore Northern shores. 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 Hsuan Keng, it was common in mangroves including Kranji, Changi and Tuas. The tree grows on both muddy and stony soil, with its roots spreading. It rarely seen on sandy shores. It requires freshwater input for a large part of the year and is commonly found on the landward margin of mangroves.

The milky sap or latex that exudes from broken leaves, bark and twigs is poisonous and can blister skin, hurt eyes and may even cause temporary blindness. ‘Buta’ means ‘blind’ in Indonesia/Malay.

Features: The tree grows to 15m tall sometimes branched at the base, thus forming multiple trunks. Roots run along the ground surface and often knotted and covered with lenticels. Tomlinson notes that the tree does not have root systems obviously specialized for mangroves and that it is also found to an elevation of 400m and he says they thus cannot be regarded as an exclusively mangrove tree. Bark gray, smooth but warty, becoming fissured. Lenticels are prominent on young twigs.

Leaves thick, oval and pointed (5-10cm long), arranged in a spiral. Young leaves are pink, old leaves turn yellow then red before dropping off. Leaves usually drop off after dry weather. Flowers tiny in long spikes.

Trees bear either male or female flowers, never both. Male flowers start as upright narrow cones when young and as they develop, elongate into longer spikes (5-10cm) that eventually form drooping yellow tassels. Male flowers are said to be “very scented”. Female flowers appear in shorter 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 dark to black seeds. The fruit capsules explode when ripe to disperse the seeds by water. The seeds have an air space within the seed coat to help them float. They don’t germinate on the parent tree.

Role in the habitat: The colorful Mangrove shield bug (Calliphara nobilis) feeds on the seeds of this tree and is often seen in large numbers when the tree is fruiting.

Human uses: According to Burkill, the timber is much used in some places for firewood and to make small articles. 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 Giersen, 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.

Sekilas mengenai Excoecaria agallocha L. (pohon buta-buta)

Deskripsi: Pohon merangas kecil dengan ketinggian mencapai 15 meter. Kulit kayu berwarna abu-abu, halus, tetapi memiliki bintil. Akar menjalar di sepanjang permukaan tanah, seringkali berbentuk kusut dan ditutupi oleh lentisel. Batang, dahan dan daun memiliki getah (warna putih dan lengket) yang dapat mengganggu kulit dan mata.

Daun: Hijau tua dan akan berubah menjadi merah bata sebelum rontok, pinggiran bergerigi halus, ada 2 kelenjar pada pangkal daun. Unit & Letak: sederhana, bersilangan. Bentuk: elips. Ujung: meruncing. Ukuran: 6,5-10,5 x 3,5-5 cm.

Bunga: Memiliki bunga jantan atau betina saja, tidak pernah keduanya. Bunga jantan (tanpa gagang) lebih kecil dari betina, dan menyebar di sepanjang tandan. Tandan bunga jantan berbau, tersebar, berwarna hijau dan panjangnya mencapai 11 cm. Letak: di ketiak daun. Formasi: bulir. Daun mahkota: hijau & putih. Kelopak bunga: hijau kekuningan. Benang sari: 3; kuning.

Perbungaan terjadi sepanjang tahun. Penyerbukan dilakukan oleh serangga, khususnya lebah. Hal ini terutama diperkirakan terjadi karena adanya serbuk sari yang tebal serta kehadiran nektar yang memproduksi kelenjar pada ujung pinak daun di bawah bunga.

Buah: Bentuk seperti bola dengan 3 tonjolan, warna hijau, permukaan seperti kulit, berisi biji berwarna coklat tua. Ukuran: diameter 5-7mm.

Ekologi: Tumbuhan ini sepanjang tahun memerlukan masukan air tawar dalam jumlah besar. Umumnya ditemukan pada bagian pinggir mangrove di bagian daratan, atau kadang-kadang di atas batas air pasang. Jenis ini juga ditemukan tumbuh di sepanjang pinggiran danau asin (90% air laut) di pulau vulkanis Satonda, sebelah utara Sumbawa. Mereka umum ditemukan sebagai jenis yang tumbuh kemudian pada beberapa hutan yang telah ditebang, misalnya di Suaka Margasatwa. Karang-Gading Langkat Timur Laut, dekat Medan, Sumatera Utara.

Penyebaran: Tumbuh di sebagian besar wilayah Asia Tropis, termasuk di Indonesia, dan di Australia.

Manfaat: Akar dapat digunakan untuk mengobati sakit gigi dan pembengkakan. Kayu digunakan untuk bahan ukiran. Kayu tidak bisa digunakan sebagai kayu bakar karena bau wanginya tidak sedap bagi masakan. Kayu dapat digunakan sebagai bahan pembuat kertas yang bermutu baik. Getah digunakan untuk membunuh ikan. Kayunya kadang-kadang dijual karena wanginya, akan tetapi wanginya akan hilang beberapa tahun kemudian.

Catatan: Getah putihnya beracun dan dapat menyebabkan kebutaan sementara, sesuai dengan namanya, yaitu buta-buta.