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Melaleuca cajuputi Powell

Melaleuca cajuputi Powell

Family

Myrtaceae

Synonyms

Myrtus saligna Burm.f., Melaleuca minor Smith, Melaleuca leucadendron (L.) L.

Vernacular Names

Malaysia

Kayu putih, gelam.

English

Cajeput (also spelt 'cajaput' or 'cajuput'), swamp tea-tree.

American

Punk tree.

Indonesia

Kayu putih (General), galam (Sundanese), gelam (Javanese, Madurese).

Cambodia

Smach chanlos.

Thailand

Samet-khao.

Vietnam

C[aa]y tr[af]m.

Geographical Distributions

The exact limits of the natural range of Melaleuca cajuputi are not known, as it has been cultivated in Asia for several centuries. The approximate boundaries cover a latitudinal range from 18°S to 12°N from tropical, northern Australia (Queensland, Northern Territory, Western Australia) through south-western Papua New Guinea, Indonesia, Malaysia to Thailand and Vietnam. Natural populations of M. cajuputi in eastern Indonesia occur on the Moluccan Islands of Buru, Seram and Ambon. M. cajuputi has been planted since 1926 in central Java for oil production, using seed from Buru. It is also planted in Malaysia.

Description

Melaleuca cajuputi is an evergreen shrub or usually single-stemmed tree that can reach up to 25(-40) m tall with an extensive root system, sometimes with aerial adventitious roots. Its bark is layered, fibrous, papery and grey to white. The crown is fairly dense, wide and somewhat silvery in appearance. The branches are smaller, with slender twigs but not drooping, and the young shoots are densely silky hairy with spreading fine hairs up to 2 mm long.

The leaves are arranged alternate, flat and silky hairy to nearly hairless. The petiole is compressed to concave-convex, measuring 3-7(-11) mm x 1.1-2.3 mm and straight or curved. The Leaves are elliptical to lance-shaped-elliptical but sometimes obliquely, measuring 5-10(-12) cm x 1-2.5(-6) cm, which is 2-10 times longer than wide, attenuated or sometimes abruptly rounded at the base. Its apex is acute or narrowly obtuse, often apiculate, thinly coriaceous, dull green, finely but obscurely dotted with oil glands, with 5-7 prominent veins and prominent reticulation.

The inflorescence is a terminal or upper-axillary spike, single or 2-3 together. The spike measures 3.5-9 cm x 2-2.5 cm. The rachis is 1-1.3 mm thick, enlarging at anthesis and densely pilose. The bracts are ovate, striate, villous and caduceus while the bracteoles are absent. The flowers are in triads, white, greenish-white or creamy. The sepal is 2.5-3 mm long, tubular and hairy while the tube is subcylindrical, measuring 1.2-1.9 mm x 1.5-2 mm and it is adnate to ovary (persistent in fruit) at the base, with 4 triangular to semicircular lobes that measure 0.7-0.9 mm x 1.2-2 mm with thin margin. There are 5 petals, measuring 2-2.7 mm x 1.8-2.3 mm, which are broadly obovate-spatulate with a short claw. The blade is suborbicular with 7 slender branched veins and streaked with glands. The numerous stamens are 7-10 mm long, white, hairless and arranged in bundles with a claw 1-3.5 mm long. There are 7-10 filaments per bundle that are attached to the upper margin of the claw. The free part is up to 8 mm long. Anthers are 0.4-0.55 mm long. The pistil is with a 3-celled ovary, which is about 1 mm long while the style is 6-9 mm long with a small stigma.

The fruit is a cup-shaped to spherical, many-seeded capsule, and measuring 3-3.5 mm x 3.5-4 mm while the orifice is 1.5-2 mm in diametre with thin valves. The seed is linear and minute.

Ecology / Cultivation

Melaleuca cajuputi is primarily found in coastal areas of the hot humid tropics. In its natural habitat, the mean maximum temperature of the hottest month is usually 31-33°C and the mean minimum of the coolest month is 17-22°C. The area has up to 230 days of over 32°C mean temperature, but with few days exceeding 38°C. The area is frost-free. The mean annual rainfall is 1300-1750 mm with a strong monsoon pattern.

M. cajuputi grows in a wide range of conditions, but most stands are found on low swampy coastal plains, sometimes immediately behind mangroves that may be flooded to a depth of over one metre during the wet season. The soils are often highly organic alluvial clays with poor drainage and very low fertility, and may be potentially acid sulphate (e.g. the Mekong Delta, Vietnam). It is resistant to fire, tolerates exposure to salt-laden winds, but not to saline waterlogged conditions.

In swamps, M. cajuputi forms pure forests, mixed open forests or woodlands associated with M. leucadendra (L.) L., Barringtonia acutangula (L.) Gaertn., Lophostemon suaveolens (Sol. ex Gaertn.) Peter G. Wilson & J.T. Waterh. and Nauclea orientalis (L.) L. On less swampy sites, it grows with a wide range of eucalypts, acacias and other melaleucas including M. dealbata S. T. Blake, M. saligna Schau. and M. viridiflora Sol. ex Gaertn. Its altitudinal range in Australia is 5-150(-250) m. By contrast, populations in the Moluccas consist of extensive and mostly pure stands that extend inland on infertile, gravelly ridges with a subsoil of red-brown clay. These sites are often colonised by Imperata grassland. Most ridges and slopes of the northern coastline of Buru and those along the Wai Apu River (which drains to the east coast) have sparse vegetation comprising open woodlands and low shrub lands of M. cajuputi at 30-400 m altitude, covering some 100,000 ha.

In western Seram, M. cajuputi occurs as an almost pure, continuous stand of some 150,000 ha along the Hoamoal Peninsula. Scattered populations occur on lowland plains and low undulating ridges at 30-150 m above sea level in Seram and also on smaller islands between Seram and Buru. Only a few scattered stands of M. cajuputi have been recorded in Ambon. In Vietnam, M. cajuputi forests once occupied most of the seasonally inundated acid sulphate soils (1.5 million ha) of the Mekong Delta, principally on Ca Mau Peninsula, in the Long Xuyen Quadrangle and on the Plain of Reeds. It is estimated that today only 120,000 ha of natural Melaleuca forest remains in the Delta.

Line Drawing / Photograph

Melaleuca_cajuputi

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References

  1. Plant Resources of South-East Asia No.19: Essential-oil plants.