Madhuca (PROSEA Exudates)
Madhuca Buch.-Ham. ex J.F.Gmel.
- Protologue: Syst. nat. 2: 773, 799 (1791).
- Family: Sapotaceae
- Chromosome number: x= unknown
Major species and synonyms
Madhuca curtisii (King & Gamble) Ridl., Fl. Mal. Pen. 5 (Suppl.): 319 (1925), synonyms:
- Ganua curtisii (King & Gamble) H.J.Lam (1925),
- Madhuca chrysocarpa (Pierre ex Dubard) Ridl. (1925),
- M. perakensis (King & Gamble) Ridl. (1925).
Madhuca motleyana (de Vriese) J.F.Macbr., Contr. Gray Herb. Harvard Univ., New Ser. 53: 18 (1918), synonyms:
- Ganua motleyana (de Vriese) Pierre ex Dubard (1908),
- G. scortechinii (King & Gamble) H.J.Lam (1925).
General: nyatoh (En).
M. curtisii :
- Malaysia: mentua taban (Peninsular).
M. motleyana :
- Indonesia: ketiau, bengku (Sumatra), nyatu bekas (Kalimantan)
- Malaysia: nyatoh ketiau (Peninsular), ketiau (Sarawak, Sabah)
- Thailand: sateeyo (peninsular).
Origin and geographic distribution
Madhuca (including Ganua Pierre ex Dubard), comprising about 100 species, has a western Malesian centre of diversity. It is distributed from India, Sri Lanka and south-eastern China to New Guinea. M. curtisii occurs in Peninsular Malaysia and Borneo and M. motleyana is found in Peninsular Thailand, Peninsular Malaysia, Sumatra, the Riau Archipelago, Belitung and Borneo.
The latex of Madhuca is used as gutta-percha, but of inferior quality. Gutta-percha is derived from the latex of Sapotaceae, primarily Palaquium spp. It has been used in the manufacture of chewing gum.
The timber of Madhuca is commercially important and is sold as "nyatoh", the lightweight to medium-weight trade group of many genera of the Sapotaceae. Oil from the seeds of M. motleyana (known as "ketia oil") is used as food ingredient and the manufacture of soap and candles. Its fruits are eaten locally.
Production and international trade
Mean annual Indonesian exports of "getah ketiau" from M. motleyana over the years 1928-1938 were 1070 t (495-2137 t), with 95% originating from south-eastern Kalimantan. The "getah ketiau" was exported to Singapore and the United States. Exports from Sarawak of "getah jangkar", which is the gutta-percha from M. motleyana, Payena leerii (Teijsm. & Binnend.) Kurz and Pouteria malaccensis (C.B.Clarke) Baehni, for the period 1949-1953 were 26-75 t annually. More recent statistics are not available.
The latex of M. motleyana contains 80% resin, a relatively high amount by comparison with the resin content of the latex of Palaquium and Payena spp. Its gutta-percha, therefore, is of lower quality. The physical properties of the getah ketiau are intermediate to those of the elastic rubber (Hevea brasiliensis (Willd. ex Juss.) Müll.Arg.) that consists mainly of cis-polyisoprene and the non-elastic, thermoplastic gutta-percha (Palaquium spp., Payena spp.) that are mainly trans-polyisoprene. When traded in the 1920s getah ketiau was much more valuable than "jelutong" (Dyera spp.).
Kernels of M. motleyana yield about 50% oil which is edible and contains 0.02-0.14% HCN. Hence, the press cake is bitter and poisonous. The oil contains about 50% oleic acid, 28% palmitic acid, 15% stearic acid and 8% linoleic acid.
- Small to large trees, with latex, sometimes up to 50 m tall, usually with columnar bole up to 100 cm in diameter, with or without buttresses, often branchless for a considerable length; outer bark smooth, cracked or fissured, usually brownish, inner bark soft and fibrous, pinkish to reddish-brown, sometimes yellowish; twigs usually slender, hairy (sometimes woolly), scurfy or glabrous at tips.
- Leaves generally arranged spirally, usually closely to loosely clustered at ends of twigs, sometimes scattered; stipules usually small and caducous, more rarely large and fairly persistent; petiole generally of even thickness throughout its length; blade simple and entire, usually obovate or elliptical, often glabrous when mature but sometimes velvety or woolly beneath; secondary veins usually fairly numerous, straight or curved, usually diminishing until inconspicuous at the leaf margin, sometimes joined near the margin by an intramarginal vein, tertiary veins usually reticulate, sometimes parallel or transverse.
- Inflorescence an axillary fascicle, 2-many-flowered.
- Flowers bisexual; sepals 4, in 2 whorls of 2, glabrous or tufted with some hairs at apex; corolla (6-)8-12(-17)-lobed, tube often about as long as the lobes, usually woolly between the stamens at throat of the tube, whitish, pale yellow or pale green; stamens (12-)14-36(-43), in 1-3 whorls inserted at the corolla throat, often with short filaments, anthers mostly mucronate at apex; pistil 1, with (5-)8-9(-15)-celled ovary and long style.
- Fruit a berry with thin to thick pericarp, 1(-4)-seeded.
- Seed with thin, hard, shiny testa, contrasting with a narrow (rarely broad), linear, pale dull scar usually with membranous albumen and thick cotyledons.
- Seedling with epigeal germination and a strongly developed taproot; first pair of leaves opposite or subopposite, subsequent leaves arranged spirally and soon similar to leaves of adult trees.
- A medium-sized tree up to 30 m tall with columnar bole up to 60 cm in diameter, buttresses absent or small, latex bluish, at first very sticky.
- Leaves evenly distributed to loosely clustered; stipules up to 5 mm long; petiole longer than 1.5 cm, blade narrowly obovate to obovate or elliptical, 7.5-15.5 cm × 3.5-7 cm, primary vein flat to rounded above, secondary veins 11-18, joined near margin, glabrous.
- Flowers greenish or white, sepals tufted with some hairs at apex, corolla 8-10-lobed, glabrous except for apex of lobes, stamens 16-22, ovary hairy.
- Fruit ovoid to ellipsoidal, about 2 cm × 1.3 cm, reddish-brown hairy, 1-2-seeded.
- Seed without or with very thin endosperm, cotyledons thick.
- A medium-sized to large tree up to 40 m tall with columnar bole up to 100 cm in diameter, buttresses absent or small and sometimes developing pneumatophores; outer bark often pinkish, latex white; crown extraordinarily dense.
- Leaves evenly distributed or loosely clustered at tips of twigs, stipules very small, petiole up to 4 cm long, blade ovate, obovate or elliptical, 5-20 cm × 2.5-8.5 cm, primary vein keeled above, secondary veins 13-23, joined in arches near margin, glabrous.
- Flowers yellow to green, with sepals pubescent outside and tufted with some dark hairs at apex, corolla 8-10-lobed, glabrous except for throat, stamens 16-22, ovary glabrous or hairy.
- Fruit ellipsoidal, 1.5-3 cm × 1-2 cm, glabrous, green, yellowish to reddish, 1-2-seeded.
- Seed without or with thin endosperm, cotyledons thick.
Growth and development
In Kalimantan, M. motleyana flowers annually and ripe fruits are observed in December-March. Its fruits are relished by wild pigs, deer, bears and birds which disperse the seeds. It has been estimated that a tree with a diameter of 60 cm is about 30 years old, which implies a mean annual diameter increment of 2 cm.
Other botanical information
Both Madhuca species have often been considered to belong to the genus Ganua Pierre ex Dubard, which was thought to differ in having characteristic tufts of hairs at the apex of the sepals, and in a thinner pericarp. These distinguishing characters are, however, not reliable and it seems better to merge Ganua and Madhuca. Usually Madhuca can be distinguished from other Sapotaceae genera by the flowers having 4 sepals and a corolla with 8 or more lobes, and by the seed having a thin endosperm and thick cotyledons.
M. curtisii is found in primary forest on low hills up to 700 m altitude and is locally common in Peninsular Malaysia in Penang and Perak. M. motleyana occurs in lowland areas up to 600 m altitude, growing in periodically inundated forest, freshwater and peat swamps, sometimes on upland locations.
Propagation and planting
Madhuca species are normally propagated by seed. Regeneration of M. motleyana is very profuse in peat swamps.
Planting of Madhuca is not practised and the latex is collected from natural forest.
Latex is collected from Madhuca throughout the year, usually by felling the tree. Immediately after felling, the tree is ringed just below the crown to prevent the latex from going to the leaves. Then, rings are made at 60-70 cm intervals and the thick exuding latex is collected in small containers. After about one hour the containers are collected and taken to where the latex is to be coagulated. One tapper can collect latex from 5-8 trees in one day.
Three M. motleyana trees of 50-60 cm in diameter yielded 8.9 kg latex from which 6.3 kg coagulated product was prepared. Usually, however, trees cut have only a diameter of 20-25 cm.
Handling after harvest
The collected latex of Madhuca is taken to a temporary shelter in the forest or to the village. The latex is put in a wooden barrel of whose interior has been coated with yellow clay to prevent the latex from sticking to it. An equal amount of boiling water is added to the latex and the mixture is stirred continuously. Coagulation starts after 10 minutes and is complete after half an hour. After cooling the coagulated mass is taken from the barrels and kneaded with the feet on wooden boards. Water is added to wash away the clay particles and the product is formed into blocks and stored under water. If it is not stored under water the coagulated latex disintegrates and crumbles in one year. Adulteration with the less valuable "jelutong" (Dyera spp.) or with coagulated latex from Moraceae or other Sapotaceae has been reported.
Genetic resources and breeding
At present both Madhuca species are only harvested for timber, but it is uncertain to what extent current harvesting is accelerating genetic erosion. There are no known germplasm collections or breeding programmes.
At present, the latex of Madhuca is no longer traded and it is very unlikely that it will be in the near future as better synthetic substitutes are available.
- Adinan, H. & Abu Bakar, H., 1988. The physico-chemical characteristics of locally available ketia oil. MARDI Research Journal 16(1): 23-26.
- Delmaar, C.N.J., 1926. Eenige mededeelingen omtrent de in de residentie Zuider- en Oosterafdeeling van Borneo voorkomende katiausoorten [Some observations on the different katiau species from south-eastern Borneo]. Tectona 19: 142-150.
- 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. p. 1230. (3rd Edition, 1950. W. van Hoeve, 's-Gravenhage, the Netherlands / Bandung, Indonesia. 1660 pp.).
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- Meijer Drees, E., 1939. Herkomst, gebruik en bestemming der voornaamste boschbijprodukten van Nederlands-Indië [Origin, use and destination of the major non-timber forest products of the Dutch East Indies]. Tectona 32: 920-1017.
- Ng, F.S.P., 1972. Sapotaceae. In: Whitmore, T.C. (Editor): Tree flora of Malaya. A manual for foresters. Vol. 1. Malayan Forest Records No 26. Longman Malaysia Sdn. Berhad, Kuala Lumpur, Malaysia. pp. 388-439.
- Pennington, T.D., 1991. The genera of the Sapotaceae. Royal Botanic Gardens, Kew, United Kingdom / New York Botanical Garden, New York, United States. pp. 154-159.
- van den Assem, J., 1953. Revision of the Sapotaceae of the Malaysian area in a wider sense. 4. Ganua Pierre ex Dubard. Blumea 7: 364-400.
- van der Laan, E. & van Meurs, L., 1926. Eenige getah- en rubbersoorten uit de Zuider- en Oosterafdeeling van Borneo [Some species yielding gutta and rubber from south-eastern Borneo]. Tectona 19: 1-27.