The name Lansium parasiticum (Osbeck) K.C.Sahni & Bennet has been proposed for this species. It has not been universally accepted yet (2014), so we are maintaining the name Lansium domesticum for the time being.

Common Name: Langsat

General Information

Langsat is an evergreen tree usually growing 10 - 30 metres tall in the wild but generally only 5 - 10 metres in cultivation. The straight, cylindrical bole is irregularly fluted and has steep buttresses that can be 2 metres wide at the base; it can be unbranched for the majority of the tree's height and up to 75cm in diameter[, , , ].
The plant is often cultivated, especially in tropical Asia, where it is considered to be one of the best fruits of the Malay region[]. It is mainly grown as a backyard or garden tree and is commonly sold in local markets[]. There are many named varieties[].

Known Hazards

An arrow poison is made from the fruit peel and the bark of the tree. Both possess a toxic property, lansium acid, which, on injection, arrests heartbeat in frogs. The seed contains a minute amount of an unnamed alkaloid and two bitter, toxic principles[].

Botanical References

Range

E. Asia - Thailand, Malaysia, Indonesia.

Habitat

Rainforests and humid river valleys[]. Rain forest, including kerengas and also found on limestone; at elevations up to 110 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	15.00 m
Growth Rate	Slow
Pollinators	Apomictic
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

Langsat is an ultra-tropical plant[]. It is a tree of tropical lowland forest and even in its native range it cannot be grown at elevations above 650 - 750 metres[]. The temperature range for growth is reported to be 12 - 40°c with the optimum between 20 - 35°c[]. It needs a humid atmosphere, plenty of moisture and will not tolerate long dry seasons[]. The annual rainfall range for growth is reported to be 1,000 - 3,000mm with the optimum between 1,400 - 2,200mm[]. It can cope with a dry season, if shade and moisture supply are adequate[]. In Java, for example, the tree grows in areas with 6 - 12 wet months if there is over 100 mm rainfall monthly[].
Young plants require shade from strong sun, but older plants can tolerate full sun, though some shade is still beneficial[]. Grows best in a slightly acid, humus-rich, well-drained, fertile soil[, ]. Dislikes heavy soils[]. Prefers a pH in the range 6 - 6.5, tolerating 5.5 - 7.5[].
The trees are shallow rooted and greatly benefit from a thick layer of organic matter to protect their numerous feeding roots[].
A slow-growing plant, the seedlings take 12 - 20 years before they bear their first crop, whilst grafted trees can beging cropping within 5 - 6 years[, , ].
Trees do not always grow and fruit well outside Asia. There are successful commercial orchards in Surinam, though the plant has been unfruitful in Honduras. It succeeds in Trinidad and Puerto Rico[].
In the Philippines, a productive tree averages 1,000 fruits per year, where it is grown in half shade interplanted with coconut[].
There are two distinct botanical varieties in the Malay Peninsula, with a third form grown in Java:-
'Pubescens' is the typical wild langsat which is a rather slender, open tree with hairy branchlets and nearly round, thick-skinned fruits having much milky latex. Although often referred to as the wild type, it is commonly cultivated and shows considerable range of form, size and quality[]. The fruit spikes are long, carrying 15 - 25 ovoid, thin-skinned fruits which exude latex until fully ripe. The taste is generally (sub)acid and refreshing. Langsat is adapted to more seasonal climates further from the equator than the following form[].
'Domesticum', often called the duku, doekoe, or dookoo, is a more robust tree, broad-topped and densely foliaged with conspicuously-veined leaflets; the fruits, borne few to a cluster, are oblong-ovoid or ellipsoid, with thin, brownish skin, only faintly aromatic and containing little or no milky latex[]. Duku bears shorter fruit spikes, usually with few fruits. Generally sweet and aromatic, the fruits are normally larger and more rounded than the langsat fruit, with a thick skin (up to 6 mm) and relatively free from latex. The trees appear to be more suited to the humid tropics[].
'Kokossan' is a form found mainly in Java - its trees have the largest flowers and most pubescent leaves. The globose, orange yellow fruits are smaller, they have a tough pericarp and contain latex. The seeds are not removed when eating the fruit - instead a hole is bitten into the skin and the juice sucked out[].
There are desirable types in each group. Some small fruits are completely seedless and fairly sweet[].
The plant commonly sets fruit (and seed) without prior fertilization (parthenocarpic)[].

Edible Uses

Fruit - raw or cooked[]. Juicy, aromatic and subacid[]. As well as being eaten out of hand, they can be candied, preserves in syrup etc[]. The fruits are borne in clusters of 2 - 30 and are about 37mm in diameter[]. Each fruit contains 5 or 6 segments of aromatic, white, translucent, juicy flesh, with 1 - 3 relatively large and very bitter seeds in each fruit[]. These seeds can sometimes cling very tightly to the flesh and can then impart their bitterness to the fruit[].
The peel of the langsat is easily removed and the flesh is commonly eaten out-of-hand or served as dessert, and may be cooked in various ways[]. Varieties with much latex are best dipped into boiling water to eliminate the gumminess before peeling[]. The peeled, seedless or seeded fruits are canned in syrup or sometimes candied[].
Although refreshing, the fruits have one of the lowest vitamin C contents of any fruit grown in Malesia[].

Medicinal

The resin is non-toxic and administered to halt diarrhoea and intestinal spasms[].
The dried pericarp is used in the treatment of diarrhoea and intestinal spasms, malaria and other fevers[]. The active principle in the pericarp appears to be a resin[].

The pulverized seed is employed as a febrifuge and vermifuge[].

The bark is poulticed on scorpion stings[]. An astringent bark decoction is taken as a treatment for dysentery and malaria[]. Leaves may be combined with the bark in preparing the decoction[].

The leaf juice is used as eye-drops to dispel inflammation[].

Agroforestry Uses:

The tree is used in reforestation of hilly areas[].

Other Uses

The peel is reportedly high in tannin[].

The fresh peel contains 0.2% of a light-yellow volatile oil, from the dried peel, a dark, semi-liquid oleoresin composed of 0.17 % volatile oil and 22% resin is obtained[].

The dried peel is burned in Java, the aromatic smoke serving as a mosquito repellent and as incense in the rooms of sick people[, ].

Wood tar, derived by distillation, is employed to blacken the teeth[].

The wood is light-brown, medium-hard, fine-grained, tough, elastic and durable, weighing 840 kg/ cu m. It is utilized in Java for house posts, rafters, tool handles and small utensils[, ].

Propagation

Langsats are commonly grown from seeds, which have a short viability and must be planted within 1-2 days after removal from the fruit[]. Sow in a shaded position in a nursery seedbed. Germination can start after 10 days, with about 90% germinating within one month. Multiple seedlings, resulting from polyembryony, are fairly common[].

Cleft-, side- and approach-grafting give good results. The budwood should be mature but not old, 6.5-9 cm long, 6-20 mm thick, and it is joined to rootstock of the same diameter about 6.5-10 cm above the soil

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