Changes

* *ssp. ''longan'' var. ''longan'' : *longan (En). *Longanier, oeil de dragon (Fr). *Indonesia, Malaysia: lengkeng

*ssp. ''longan'' var. ''obtusus'' : *Thailand: lamyai khruer, lamyai tao.

*ssp. ''malesianus'' var. ''malesianus'' : *Malaysia: mata kucing (Peninsular Malaysia and Sabah), isau, sau, kakus (Sarawak)

The edible portion of export quality fruit of 3 cultivars ranges from 67 to 78% of the whole fruit. Composition of longan per 100 g edible portion is: water 72.4 g, protein 1.0 g, fat 0.5 g, carbohydrates 25.2 g, fibre 0.4 g, ash 0.5 g, Ca 2 mg, P 6 mg, Fe 0.3 mg, vitamin A 28 IU, vitamin B₁0.04 mg, vitamin B₂0.07 mg, niacin 0.6 mg and vitamin C 8 mg. The energy value averages 458 kJ/100 g. The sugar content is very high. The composition of "mata kucing" fruit is not very different, but carbohydrates - and energy values - are much lower, whereas much higher figures are given for mineral content.

*Tree, up to 40 m tall and 1 m trunk diameter, sometimes buttressed, exceptionally a scandent shrub; branches terete with 5 faint grooves, sometimes warty lenticellate, rather densely ferruginous tomentose. *Leaves 2-4(-6)-jugate, axial parts mostly densely hairy; petiole 1-20 cm, petiolules 0.5-35 mm long; leaflets elliptical, 3-45 cm × 1.5-20 cm, 1-5 times longer than wide, chartaceous to coriaceous, above often tomentose in basal part of midrib, beneath thinly tufted-tomentose mainly on midrib and nerves. *Inflorescences usually terminal, 8-40 cm long, densely tufted-tomentose; cymules (1-)3-5-flowered; pedicels 1-4 mm; bracts patent, 1.5-5 mm long; flowers yellow-brown; calyx lobes 2-5 mm × 1-3 mm; petals 5, 1.5-6 mm × 0.6-2 mm, densely woolly to glabrous; stamens (6-)8(-10), filament 1-6 mm. *Fruit drupaceous, 1-3 cm in diameter, lobe(s) broad-ellipsoid to globular, smooth to warty or sometimes up to 1 cm aculeate, sometimes granular, glabrescent, yellow-brown. *Seed globular with shining blackish-brown testa; seed enveloped by a thin fleshy, translucent white arilloid.

In the panicles of "mata kucing" male and hermaphrodite flowers occur. Flowering lasts only 1-2 weeks, the period varying from late June to mid-October in Sarawak. Pollination is mainly by insects such as ants, flies and honey bees ( ''Apis cerana'' , ''A. florea'' and also ''A. dorsata'' ). Flowering is often prolific but fruit set is quite low and 2 weeks after flowering, when fruitlets measure 1 cm, many are shed. The fruit ripens about 4 months after bloom.

The two subspecies and five varieties of ''D. longan'' , listed above, are distinguished mainly by differences in the leaflets.

Within ssp. ''malesianus'' , var. ''malesianus'' shows the greatest variation in Borneo. The fruits are globular to slightly oblong and smooth to warty. In Peninsular Malaysia, the most common form of this taxon is the one with globose smooth fruits which turn brown when ripe. This is the true "mata kucing" and has usually been identified as ''Euphoria malaiensis'' . It has a very thin arilloid and is hardly worth eating. This form also exists in Borneo and Sumatra. The more superior forms are found in Sarawak, all with densely thick warty fruits and thicker arilloids. These forms can be roughly grouped into three types based on the fruit characteristics: the "isau" with fruits which are globular and remain green when ripe, the "sau" with fruits which are slightly oblong and also remain green when ripe, and the "kakus" with globular fruits which turn brown when ripe. The leaves, flowers and tree forms also differ. The "kakus" is more widespread in Sarawak, while the "isau" and "sau" are mainly confined to the river banks of the Rajang river and to the Bareo valley.

Var. ''echinatus'' differs from var. ''malesianus'' in that the fruits have rather long spines resembling the rambutan ( ''Nephelium lappaceum'' L.). This variety is found in Sabah where the "kakus" also exists.

The "mata kucing" thrives in the humid tropical lowlands near sea level, within about 10°from 10° from the equator. The trees occur mainly in the substage or understorey in primary or sometimes secondary forests. Rainfall ranges from 2500 mm to more than 4000 mm per year associated with a mean air temperature of 25-30°C and a relative humidity of 65-95%. In Sarawak, the trees grow on alluvial soil, often on river banks. In other areas the trees grow on a wider range of soil types. A pH range of 4.5-6.5 is common in this region.

The University of Agriculture Malaysia with its branch campus at Bintulu, Sarawak, is now the largest collector of germplasm of ''D. longan'' ssp. ''malesianus'' . The great diversity in Sarawak offers a great opportunity to select superior material. Explorations in remote areas have been regularly made to identify trees with good quality fruit - thick flesh, fruit in consolidated panicles - and to collect budwood.

The superior races of the spp. ''malesianus'' , in particular the var. ''malesianus'' in Sarawak and other parts of Borneo, may offer an attractive alternative to longan for the humid tropical lowlands.

* van Welzen, P.C., Lamb, A. & Wong, W.W.W., 1988. Edible Sapindaceae in Sabah. Nature Malaysiana 13: 10-25. | '''10''' | * Wong, K.C., Ibrahim Yusof, Pearce, K.G. & Alau Tayan, D., 1988. Isau - A potential tropical longan (Dimocarpus longan) of Sarawak. Proceedings of the Third National Biology Symposium, Subang Jaya (in print).