Sindora (PROSEA Exudates)

Plant Resources of South-East Asia Introduction

List of species

Sindora Miq.

Protologue: Fl. Ind. Bat., suppl. 1(2): 287 (1861).

Family: Leguminosae

Chromosome number: x= 12

• Sindora inermis Merr., Philipp. Journ. Sc. 10: 314 (1915).

• Sindora sumatrana Miq., Fl. Ind. Bat., suppl. 1(2): 288 (1861).

• Sindora supa Merr., Philipp. Journ. Sc., Bot. 1, suppl. 3: 198 (1906).

• Sindora velutina J.G.Baker, Fl. Brit. India 2: 269 (1878), synonyms: S. parvifolia Backer ex K.Heyne (1927), S. parvifoliola Symington (1938).

General: sepetir.

S. inermis :

• Philippines: kayu-galu (Magindanao), nito-nitong puti (Bikol), sinsud (Sulu).

S. sumatrana :

• Indonesia: sindur, tampar hantu (Palembang, Sumatra).

S. supa :

• Philippines: supa (Bikol, Tagalog), baloyong (Batangas), manapo (Tayabas).

S. velutina :

• Indonesia: sindur, kaparantu (Sumatra), kayu bulan (East Kalimantan)
• Malaysia: sepetir beludu besar, sepetir beludu kechil (Peninsular), ensunut (Sarawak).

Sindora consists of about 20 species confined to Indo-China and western and central Malesia, except for one species which occurs in tropical Africa (Gabon). It is absent from the Lesser Sunda Islands and New Guinea. S. inermis is found in the Philippines (southern Luzon, Mindanao and the Sulu Archipelago), S. sumatrana in Sumatra and Bangka, S. supa in the Philippines (Luzon, Mindoro) and S. velutina in Peninsular Malaysia, Sumatra and Borneo.

Many Sindora species yield a wood-oil used for making paints and varnishes, for illumination, for caulking boats and to adulterate other oils. The wood-oil of S. inermis has a pleasant persistent odour and is used in the perfume industry. It is sometimes used medicinally against skin diseases and rheumatism and has been applied in the manufacture of birdlime.

Sindora yields an important timber (sepetir) of which the sometimes attractively figured wood is highly appreciated. It is particularly used for bowling alleys. The aril of the seed of S. siamensis Teijsm. ex Miq. is sometimes used as a substitute for betel (Areca catechu L.). The fruits of S. sumatrana are widely used in local medicine against fever, serious bleeding in the uterus and scalp eczema. The pods of other species are used in compound traditional medicines, particularly in connection with childbirth.

Small quantities of wood-oil from S. inermis are exported from the Philippines to Singapore for the perfume industry. The medicinal fruits of S. sumatrana used to be exported from Indonesia.

The export of sepetir timber is more important.

Sindora wood-oil from Malaysia has a clear light brown colour, a pleasant smell, and a gummy consistency. The specific gravity is 0.9657 and the optical rotation at 29°C is +27.8°. Distillation with steam gives 65% colourless essential oil with an optical rotation of -6.5°. Wood-oil from S. supa from the Philippines is a light yellow, non-drying, transparent oil and has a specific gravity of 0.9202 and optical rotation of -31.3°. It consists mainly of sesquiterpenes and is soluble in organic solvents except alcohol. Sindora wood-oil originating from Pontianak (West Kalimantan) is pale brown with a specific gravity of 0.9550, a refractive index of 1.5119, and an optical rotation of -25.0°. The wood-oil yields 53% essential oil after steam distillation with the following physical properties: specific gravity 0.9142, refractive index 1.4958, and optical rotation -10.4°. The wood-oil of S. velutina has been analysed. After distillation the oil had the following physical properties: specific gravity 0.946 and boiling range 250-280°C. This oil consists of sesquiterpenoid hydrocarbons with three major compounds, namely α-copaene (41.3%), β-cubebene (15.4%) and β-cadinene (7.2%). The fruits of S. sumatrana yield an essential oil which almost exclusively contains sesquiterpene oxides and sesquiterpene alcohols.

The density of the wood of the species yielding wood-oil is 530-830 kg/m³ at 15% moisture content.

• Usually medium-sized but sometimes large, briefly deciduous trees, 20-35(-46) m tall with cylindrical bole having a diameter of up to 100(-180) cm, non-buttressed or flaring out at base or with steep thick buttresses; bark smooth, thin and brittle, rugulose with distant, prominent lenticels, dark purplish-grey and often flecked with green, brown or yellow.
• Leaves alternate, paripinnate, 2-10-jugate; leaflets opposite, shortly stalked, usually firmly leathery, often reticulately veined on both surfaces and slightly asymmetrical, the midrib on the lower surface often ending in a gland.
• Inflorescence made up of solitary or gregarious panicles, often velvety pubescent.
• Flowers bisexual, zygomorphic, sessile or shortly pedicelled; calyx with a short tube, tawny velvety pubescent, and 4 lobes, usually unequal in size, with or sometimes without spinescent outgrowths; petal 1, fleshy in the lower half, with an indistinct, yellow or red claw; stamens (9-)10, 9 fused in hirsute sheath, the uppermost one free and reduced to a short staminode; usually 2 stamens are better developed than the others; ovary with a short, free stipe, with 2-5(-more)-ovules, flat, hirsute at least along the suture, style recurved, stigma small.
• Fruit a flat pod, circular to oblong, dehiscent with 2 valves, smooth but more often set with hollow spines.
• Seeds 1-2, flat, hard and stony, black on top of a red or yellow aril about as large as the seed.
• Seedling with epigeal germination; hypocotyl elongate; first two leaves alternate, leaflets larger and thinner than those of mature trees.

S. inermis.

• Tree, up to 30 m tall, bole 75-95 cm in diameter.
• Leaves 2-4-jugate; petiole 2-4 cm long, rachis 8-15 cm long; leaflets elliptical to ovate or obovate, 6-13 cm × 4-7 cm.
• Inflorescence 10-15 cm long with brown, glabrous flowers.
• Fruit broadly ellipsoidal, up to 7 cm × 5 cm, unarmed, glabrous.

S. sumatrana.

• Tree, medium-sized to large.
• Leaves often 3-jugate; petiole up to 3 cm long, rachis up to 9.5 cm long; leaflets elliptical to obovate-oblong, 6-12 cm × 2-6 cm, glabrous.
• Infructescence paniculate, up to 13 cm long; fruit flattened globose to broadly ellipsoidal, up to 4 cm long, with many short but stout spines with a swollen base and abundant resin.
• Seed subglobose, flattened, about 1 cm in diameter, black, aril irregular.
• No information is available on the flowers.

S. supa.

• Tree, 15(-30) m tall and 30(-180) cm in diameter.
• Leaves 2-4-jugate; petiole 1-2.5 cm long, rachis 1-7 cm long; leaflets elliptical, 2-8 cm × 2-4 cm.
• Inflorescence paniculate, up to 20 cm long; calyx lobes 6-12 mm long; petal sublanceolate, 10-12 mm long; 2 perfect stamens with anthers 3.5 mm long, other anthers much smaller.
• Fruit broadly ellipsoidal, 4-5 cm × 3-3.5 cm, with straight sharp spines 5 mm long.
• Seeds 2-4, ovoid, 3 cm × 2 cm, black.

S. velutina.

• Tree, 15-50 m tall, 20-95 cm in diameter, densely rusty pubescent on twigs and leaf undersides.
• Leaves 3-7-jugate; petiole 2-5 cm long, rachis 5-20 cm long; leaflets ovate to elliptical, 3-14 cm × 1.5-7 cm.
• Inflorescence paniculate, up to 20 cm long; calyx lobes 11-13 mm long; petal lanceolate, 10-12 mm long, woolly outside; 2 perfect stamens with 3-4 mm long anthers, other anthers much smaller.
• Fruit ovoid, 6-15 cm × 5-8 cm, with sharp spines 4 mm long.
• Seed irregular, flattened ovoid, 1.5-2 cm long and wide, purple-black.

Sindora trees are deciduous and may remain leafless for several weeks, the young leaves being bronze or pale green. Flowers appear shortly after the new leaves. S. velutina flowers are pollinated by small social bees. Fruits take about 2 months to reach maturity. The waxy aril of the seeds is especially attractive to rodents, which disperse the seeds.

Sindora is a well-defined genus and rather easy to recognize by its pubescent flowers with a single fleshy petal, its peculiar pods and arillate seeds. It belongs to the subfamily Caesalpinioideae and the tribe Detarieae.

In addition to the species dealt with here in more detail, the following species have also been reported as producing wood-oil: S. beccariana Backer ex de Wit (tall tree from Borneo, pod with straight sharp spines); S. coriacea Maingay ex Prain (tree 20-30 m tall from Thailand, Peninsular Malaysia, Sumatra and Borneo, leaves glabrous, flowers yellow to red and pods unarmed); S. javanica (Koord. & Valeton) Backer ex K.Heyne (tree 20-30 m tall, in Java on poor soils, the pods have an excessive resin excretion, the flower has no free staminode); S. leiocarpa Backer ex K.Heyne (tree 25-45 m tall from Sumatra and Borneo, inflorescences abundant and fragrant, pods unarmed); S. siamensis Teijsm. ex Miq. (synonym: S. cochinchinensis Baill.) (small tree up to 15 m tall from Thailand, Indo-China and Peninsular Malaysia; fruits are armed (var. siamensis ) or unarmed (var. maritima (Pierre) K. & S.S.Larsen) and are used as a substitute for areca nut in betel chewing); and S. wallichii Graham ex Benth. (tree 20-30 m tall from Peninsular Malaysia, Sumatra and Borneo, flowers bright red, pod dark purple with a velvety brown pubescence).

Several species are poorly known and certainly deserve more attention from field botanists.

Sindora trees occur usually scattered, sometimes gregarious, in lowland dipterocarp forest on flat land and hillsides, up to 800 m altitude. They generally favour well-drained soils, which are at least moderately fertile. Occasionally, they are found near the banks of brooks or small rivers. S. inermis may also occur along the seashore and near the mangrove zone, while S. sumatrana prefers periodically inundated sandy sites, S. supa is especially found on limestone ridges in regions with a distinct dry season and S. velutina prefers dryland forests.

Sindora seeds survive for more than 3 years without any specific treatment. Germination is usually delayed. When the seed-coat is mechanically scarified on one or both sides of the seed, and the seeds are soaked in water at room temperature for 24 hours, the germination rate within one month is about 70%. An effective method of mechanical scarification is to scrape off the protrusion of the seed-coat located next to the hilum. Treatment with dilute sulphuric acid or hot water is much less successful. However, seeds treated with concentrated sulphuric acid for one hour may give 80% germination.

For seedlings of S. supa a 1:1 mixture of sand and humus appeared to be the most satisfactory potting medium. When potted in this mixture seedlings attain an average height of about 20 cm after 7 months. A mixture of ordinary garden soil and sand (2:1) gives slightly inferior results.

In logged-over forest the regeneration of Sindora is often abundant. Usually the number of seedlings is larger than in undisturbed forest. From Peninsular Malaysia an average of one large tree (over 60 cm in diameter) per 5 ha of undisturbed forest has been reported, although locally Sindora is more common: up to one large tree per 2 ha.

During very rainy weather in the Philippines, Sclerotium rolfsii has been observed to attack very young Sindora seedlings under 20 cm tall causing "damping-off".

Wood-oil of Sindora is obtained by cutting downward slanting cavities in the stem. They may cover up to half of the circumference of the tree and go as deep as the centre of the stem. In each cavity the wood-oil collects and the flow of oil is increased by a fire which is maintained for half a day. The wood-oil is subsequently removed from the cavities. This destructive method of harvesting wood-oil was practised in the Philippines, Indonesia and Malaysia. Occasionally, whole trees are cut and chopped to obtain the wood-oil.

A freshly cut tree of S. supa in the Philippines may yield about 10 litres of wood-oil. A single S. velutina tree 40 m tall and 85 cm in diameter may yield 30 litres of oil.

The wood-oil of Sindora can be used directly. Sometimes the essential oils are extracted by steam distillation.

Most Sindora species are uncommon and occur scattered. Large-scale exploitation of forest, as practised in many locations, puts these species at risk of extinction. Proper and sustainable management of the forest should guarantee survival of its component trees, including Sindora.

At present, the wood-oil of Sindora is not traded and there seems to be no future for its increased utilization. Sindora timber will remain of importance, provided the forests in which Sindora occurs as scattered trees are wisely managed.

• de Wit, H.C.D., 1949. Revision of the genus Sindora Miquel (Legum.). Bulletin of the Botanic Gardens, Buitenzorg, Series 3, 18: 5-82.
• Ding Hou, 1996. Sindora. In: Kalkman, C., Kurkop, D.W., Nooteboom, H.P., Stevens, P.F & de Wilde, W.J.J.O. (Editors): Flora Malesiana. Series 1, Vol. 12. Rijksherbarium/Hortus Botanicus, Leiden University, Leiden, the Netherlands. pp. 691-709.
• Handelsmuseum, 1937. Inlichtingen en onderzoekingen van de afdeeling Handelsmuseum in 1936 [Information and research from the Trade Museum division in 1936]. Mededeelingen Afdeling Handelsmuseum No 17. Afdeeling Handelsmuseum van het Koloniaal Instituut, Amsterdam, the Netherlands. 159 pp.
• Heyne, K., 1927. De nuttige planten van Nederlands-Indië [The useful plants of the Dutch East Indies]. 2nd edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch-Indië. pp. 727-730. (3rd Edition, 1950. W. van Hoeve, 's-Gravenhage, the Netherlands / Bandung, Indonesia. 1660 pp.).
• Ibrahim Jantan & Nor Azah, M.A., 1991. Volatile components of Sindora velutina. Journal of Tropical Forest Science 4(2): 142-146.
• Lasmarias, V.T., 1979. Survival and growth of akle (Albizzia acle (Blanco) Kosterm.) and supa (Sindora supa Merr.) in various potting media. Sylvatrop 4(3): 161-166.
• Mejia, A.S., 1953. Sclerotium wilt of supa (Sindora supa Merr.). Philippine Journal of Forestry 9(1-4): 119-132.
• Sambas, E.N., Laming, P.B., Ani Sulaiman & Sosef, M.S.M., 1993. Sindora Miq. In: Soerianegara, I. & Lemmens, R.H.M.J. (Editors): Plant resources of South-East Asia No 5(1). Timber trees: major commercial timbers. Pudoc Scientific Publishers, Wageningen, the Netherlands. pp. 434-442.
• West, A.P. & Brown, W.H., 1921. Philippine resins, gums, seed oils, and essential oils. In: Brown, W.H. (Editor): Minor products of Philippine forests. Vol. 2. Bulletin No 22. Bureau of Forestry, Department of Agriculture and Natural Resources. Bureau of Printing, Manila, Philippine Islands. pp. 38-40.
• Whitmore, T.C., 1972. Leguminosae. In: Whitmore, T.C. (Editor): Tree flora of Malaya. A manual for foresters. Vol. 1. Longman Malaysia Sdn. Berhad, Kuala Lumpur, Malaysia. pp. 270-273.

H.C. Ong