(longan)

(李志杰)

Scientific name: Dimocarpus longan Lour. The seeds are spherical, bright dark brown, shaped like the eyes of the legendary dragon, so they are called longan. Sapindaceae, genus Longan (20 species of this genus, produced in tropical Asia. 4 species in China). Evergreen tree, up to 15 meters high. Bark reticularly lobed. Even-numbered pinnate compound leaves, alternate, 15 to 30 cm long with stalk; 3 to 5 pairs of leaflets, thin leathery, entire edge, oblong or oblong-lanceolate, 6 to 15 (20) cm long, with no leaves on both sides Hair, light green above. The panicle is axillary and terminal, 12-15 cm long; the flowers are small, mixed, yellow and white; there are 5 sepals and petals; 8 stamens; 2-3 pistils and carpels. The drupe is spherical, 1.2 to 2.5 cm in diameter, with rough or smooth outer covering. The seeds are dark brown and surrounded by arils. Blooms in spring and ripens in late summer. Produced in China (South China, Southwest) and Southeast Asia, and also introduced in Japan. In the dry and hot basins, valleys and hills of western Hainan Island, China, it is often the most dominant species in the second layer of trees in deciduous rainforests. There are natural pure forests in the Fenglin Stone Mountain in southwestern Guangxi, and there are also wild forests in southern Yunnan. Longan is more cold-resistant, drought-resistant and barren-resistant than lychee, and is suitable for growing in acidic soil and calcareous soil. China's economic cultivation area is limited to the southeastern subtropical region, with Fujian having the highest yield. Although it is cultivated sporadically in the southern edge of the central subtropical zone, the fruit is small and fleshy and has no commercial value. Southern and northern Sichuan have higher latitudes, and are also cultivated in local warm valleys. Vertically distributed, the eastern part is generally below 500 meters above sea level, and the southern part of Yunnan is as high as 1,800 meters. Propagation methods include grafting, layering, cuttings, etc. Longan is a famous fruit. Each 100 grams of pulp contains 68.7 to 144.8 mg of vitamin C, 59% sugar and 5.6% protein. The dried pulp is called Gui Yuan, which is a fruit and tonic that has the effect of strengthening the brain and body. The wood has beautiful color, high strength, and is very hard and heavy. It is suitable for use in high-end furniture, construction, vehicles, boats, and joinery. The bark contains 10 to 13 tannins and can be used as a dye. Young leaves and buds can be substituted for tea. It has a long flowering period and is luxuriant, making it an excellent nectar source. It is a third-level key protected plant in China.