Dimocarpus longan Lour.
Family
Sapindaceae
Synonyms
Dimocarpus longan Lour., Euphoria longana Lamk nom. illeg., Nephelium longana Cambess.
Vernacular Names
| Malaysia, Indonesia | Lengkeng. |
| English | Longan. |
| Burma (Myanmar) | Kyet mouk. |
| Cambodia | Mien. |
| Laos | Lam nhai, nam nhai. |
| Thailand | Lamyai pa. |
| Vietnam | Nhan. |
| French | Longanier, oeil de dragon. |
Geographical Distributions
Some authors limit the area of origin to the mountain chain from Burma through southern China and others extend it to south-west India and Sri Lanka including the lowlands. The crop is mainly grown in south China, Taiwan and north Thailand with small acreages elsewhere in Indo-China as well as Queensland (Australia) and Florida (United States) and scattered trees at higher elevations in Southeast Asia.
Description
Dimocarpus longan is a tree that can reach up to 40 m tall, measuring 1 m trunk diametre with sometimes buttressed and exceptionally a scandent shrub.
The branches are cylindrical with 5 faint grooves, sometimes with warty lenticellate and rather densely ferruginous tomentose.
The leaves are 2-4(-6)-jugate and the axial parts are mostly densely hairy. The petiole is 1-20 cm long while the petiolules are 0.5-35 mm long. The leaflets are elliptical, measuring 3-45 cm x 1.5-20 cm where 1-5 times longer than wide, chartaceous to coriaceous while at above are often hairy in basal part of midrib and with thinly tufted-hairy beneath mainly on the midrib and nerves.
The inflorescences are usually terminal, measure 8-40 cm long and with densely tufted-hairy. The cymules are (1-)3-5-flowered. The pedicels are 1-4 mm long. The bracts are patent and measure 1.5-5 mm long. The flowers are yellow-brown. The sepal lobes measuring 2-5 mm x 1-3 mm. There are 5 petals measuring 1.5-6 mm x 0.6-2 mm and with densely woolly to hairless. The stamens are (6-)8(-10) while the filament is 1-6 mm long.
The fruit is a drupaceous, measuring 1-3 cm in diameter, broad-ellipsoid to globular lobe(s), smooth to warty or sometimes with the aculeate measures up to 1 cm long, sometimes granular, glabrescent and yellow-brown.
The seed is globular with a shining blackish-brown testa, enveloped by a thin fleshy and with a translucent white arilloid.
Ecology / Cultivation
D. longan is a subtropical tree that grows well in the tropics but requires a prominent change of seasons for satisfactory flowering. A short (2-3 months) but cool (mean temperature 15-22°C) winter season brings out a prolific bloom; in this respect longan is less demanding and more predictable than lychee. From fruit set onwards, the high temperatures do not hamper development, but nights should not be warmer than 20-25°C. Ample soil moisture is needed from fruit set until maturity and suitable annual precipitation is about 1500-2000 mm.
D. longan thrives on rich sandy loams where it does well on oolitic limestone but moderately acid sandy soils are more marginal and on organic muck soils flowering are deficient. It is probably because the shoot growth continues for too long. In northern Thailand, D. longan orchards are often situated on the lighter soils along former river courses and a ribbon of trees winding between the sawahs. The roots grow down 2-4 m to the water table.
Line Drawing / Photograph
References
- Plant Resources of South-East Asia No. 2: Edible fruits and nuts.
