Xylocarpus (PROSEA Dyes and tannins)
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Introduction |
- Protologue: Naturforscher (Halle) 20: 2 (1784).
- Family: Meliaceae
- Chromosome number: 2n= 52:X. granatum, X. moluccensis
Major species and synonyms
- Xylocarpus granatum Koenig, Naturforscher 20: 2 (1784), synonyms: Carapa obovata Blume (1825), Xylocarpus obovatus (Blume) Juss. (1830).
- Xylocarpus mekongensis Pierre, Fl. For. Cochinch.: pl. 359 B (1897), synonyms: Carapa moluccensis Watson (1928) non Lamk, Xylocarpus gangeticus (Prain) Parkinson (1934), Xylocarpus australasicus Ridley (1938).
- Xylocarpus moluccensis (Lamk) M. Roemer, Prospect Fam. nat. syn. monogr. 1 (Hesper.): 124 (1846), synonym: Carapa moluccensis Lamk (1785).
Vernacular names
- X. granatum : Indonesia: nyiri (northern Sumatra)
- Malaysia: nyireh hudang, nyireh bunga, niris bunga
- Philippines: tabigi (Tagalog, Bisaya), piagau (Tagalog), kolimbaning (Ilokano). Singapore: nyireh bunga
- Cambodia: châm'-puu praèk, t'bôôn
- Thailand: kra buun khaao, ta buun, ta buun khaao (central, peninsular)
- Vietnam: xu'o'ng cá, dang dinh.
- X. moluccensis : Indonesia: nyiri batu (northern Sumatra), nyiri gundik (Java)
- Malaysia: nyireh batu, nyiris, delima wanita
- Philippines: piagau (Tagalog, Bisaya), migi (Pampango). Singapore: nyirih batu
- Thailand: ta buun dam (general), ta ban (central, peninsular)
- Vietnam: xu'o'ng cá.
Confusion of the species in the vernacular names cannot be excluded, and is probably even common. Vernacular names for X. granatum and X. moluccensis are certainly also used for X. mekongensis .
Origin and geographic distribution
X. granatum and X. moluccensis have very large areas of distribution, from East Africa and Madagascar through India, Sri Lanka, and South-East Asia to tropical Australia and Polynesia. X. mekongensis is found from India to Papua New Guinea and tropical Australia. The three species are all found throughout South-East Asia.
Uses
The bark of the bole is rich in tannin. It is used for tanning heavy hides into sole and heavy leather, and for toughening fishing-nets. It is sometimes used to dye cloth brown.
The wood is a good mahogany-like timber, but as the trunk is usually crooked and hollow, long straight pieces cannot be cut. It is used in boat building, and for nails, house-posts, small objects like tool handles, and for furniture, but it is not resistant to termites. In India the wood is found suitable for second grade pencils. It can also be used as firewood.
The astringent bark has some medicinal uses. It is reported to cure dysentery, diarrhoea and other abdominal troubles, and as a febrifuge. The seeds are also used medicinally.
Production and international trade
The bark is used only locally for tanning purposes because natural supply is not abundant. Xylocarpus is usually not found in pure stands and its bark is thin. The wood is also of local importance only.
Properties
Different parts of the plant contain tannin: bark, wood, leaves, and fruits. However, the bark of mature trees is richest in tannin, containing 20-34% on dry matter base. The tannin produces a reddish, tough leather, but nothing is known about its constitution.
The seeds yield small quantities (1-2%) of oil. The wood is reported to contain 0.1% gedunin.
The wood is moderately heavy, 630-790 kg/m2, hard and durable. It has a brown to red colour (sapwood brownish-white), shrinks little and is reported difficult to saw and finish. It is straight or interlocked-grained. Vessels moderately small to medium-sized. Parenchyma with terminal bands, diffuse parenchyma consisting almost entirely of scattered files of crystalliferous cells, other parenchyma scarce to vasicentric. Rays 4-6 cells wide.
Description
Medium-sized, evergreen or deciduous, glabrous trees, up to 22 m tall, and with trunk up to 1 m diameter, sometimes buttressed; root system often developing either pneumatophores or ribbon-like surface roots; bark fissured or scaly. Leaves alternate, paripinnately compound, with (1-)2-3 pairs of leaflets, exstipulate; leaflets elliptic or (ob)ovate, 4-17 cm × 2-9 cm. Flowers in axillary panicles, functionally unisexual, 4-merous, 3-5 mm in diameter, with a well-developed disk, shortly united sepals and more or less free, creamy-white petals; stamens 8, united into a tube; ovary 4-locular, style short, stigma capitate, large. Fruit a globose, woody capsule, up to 25 cm in diameter, 6-18-seeded. Seeds more or less tetrahedral, up to 6 cm long, brown. Germination hypogeal, seedling initially with scale leaves, first leaves simple.
X. granatum : root system elaborated above the ground with narrow, undulating, ribbon-like extensions; buttresses well-developed; trunk surface smooth, pale, blotched greenish or yellowish, peeling in patches; leaflets more or less elliptic and obtuse-rounded; fruit up to 20 cm in diameter.
X. mekongensis : root system developing blunt, not ribbon-like pneumatophores; buttresses very short or even absent; trunk surface rough, dark brown, fissured, peeling in narrow strips; leaflets more or less elliptic and obtuse-rounded; fruit up to 12 cm in diameter.
X. moluccensis : root system not elaborated; trunk lacking buttresses and with a longitudinally fissured surface; leaflets more or less ovate and subacuminate; fruit up to 8 cm in diameter.
Growth and development
Trees are usually evergreen, even in seasonal climates, but are sometimes reported as deciduous, for instance in the non-seasonal climate of Sarawak. They sucker basally when they are damaged, and depauperate plants may develop several trunks.
Flowers are functionally unisexual, male flowers having a nonfunctional, rather slender ovary, female flowers having nonfunctional stamens either never dehiscent or with sterile pollen. It has been observed that certain individuals, although flowering profusely, never produce fruit; this suggests that dioecism sometimes occurs. Flowers are probably pollinated by short-tongued insects like bees.
The corky testa of the seed represents an adaption to dispersal by water, and seeds may start to germinate while still floating.
Other botanical information
The three species are very similar, and consequently have often been confused. Therefore, interpretation of data from literature is difficult, and it is impossible to disentangle the species completely. However, it is likely that species which are probably closely related will have many properties in common. The species differ most clearly in bark and root characters, and should easily be distinguishable in the field, but not in the herbarium.
It has been suggested that X. mekongensis may have arisen through hybridization between the other two species. In fact, intermediates between X. granatum and X. moluccensis appear to be widespread and locally numerous. More information is needed on their botany, ecology and distribution, including the occurrence of hybrids.
Ecology
X. granatum and X. mekongensis are mangrove plants, found in tidal mud of mangrove swamps, especially towards their upper limits. X. moluccensis usually grows on sandy or rocky beaches, in coastal scrub just above the high-water mark, but it has also been reported from typically mangrove environments. X. granatum in Indonesian mangrove forest has been recorded to tolerate a salinity of 0.1-3%.
Harvesting
The bark is peeled from the tree for use in local tanneries. The tree recovers easily from the peeling. Usually the bark is directly used in the tannery or for toughening nets.
Prospects
The cultivation of Xylocarpus in the more dry mangrove areas is worth considering. They might be interesting plants for industrial tannage because the trees recover easily after the bark has been removed. In addition, they are easy to propagate and they have a comparatively high tannin content.
Literature
- Bhatnagar, S.S. (Editor), 1950. The wealth of India. Raw materials. Vol. 2. New Delhi. pp. 74-75.
- Tomlinson, P.B., 1986. The botany of mangroves. Cambridge University Press, Cambridge, Great Britain. pp. 274-282.
- Watson, J.G., 1928. Mangrove forests of the Malay Peninsula. Malayan Forest Records 6: 1-275.
- White, F. & Styles, B.T., 1963. Meliaceae. In: Exell, A.W., Fernandes, A. & Wild, H. (Editors): Flora Zambesiaca. Vol. 2(1). pp. 293-297, tab. 57.
Authors
Rudjiman
