楝科（Meliaceae）的地理分布

GEOGRAPHICAL DISTRIBUTION OF CHINESE MELIACEAE

楝科为泛热带分布科，全世界有５１属，约５５０—６００种，分布于旧世界热带地区有４６属，热带美洲有８属．热带亚洲和热带非洲为楝科两大现代分布中心．中国楝科共１５属，６１种，占世界属总数的２９％，种总数的１０％。中国楝科的分布是在全球楝科分布区的边缘，主要分布于中国西南部及南部诸省，种类由西南向东南递减。中国楝科属的分布区类型可归为５类：１．热带亚洲、非洲和中南美洲间断分布（１属）；２．旧世界热带分布（３属）；３，热带亚洲至热带大洋洲分布（２属）；４．热带亚洲至热带非洲分布（１属）；５．热带亚洲分布（８属）。中国楝科种的分布区类型仅有２类：１．热带亚洲分布（３１种）；２．中国特有分布（３０种）。楝科植物的起源推断在早白垩纪。中国楝科植物由印度—马来西亚成分及特有成分组成。热带亚洲的楝科植物主要是通过中南半岛和中国云南。广西和海南等地发生联系，而菲律宾和台湾之间可有直接的联系。

Meliaceae is a pantropical family comprising about 51 genera and 550-600 species mainly distributed in tropical Old World.Tropical Asia and Tropical Africa are the two present distribution centres of the family.There are 15 genera and 61 species in China which constitute 29% and 10% of the total genera and species in the family,respectively,and they mainly distribute in the southwest and the south of China.The 15 genera of chinese Meliaceae may be divided into 5 distribution patterns:1.Tropical Asia,Africa and Central to South America disjunction(1 genus),2.Old World tropics(3 genera);3.Tropical Asia and Tropical Australasia(2 genera),4.Tropical Asia to Tropical Africa(1 genus);5.Tropical Asia(8 genera).The species distribution of Chinese Meliaceae may be divided into 2 types:1.Indo-Malesian(31 species);2.Endemic to China (29 species).The Meliaceae of tropical Asia entered Yunnan,Guangxi and Hainan of China through Indo-China,while the Meliaceae in the Philippines is in direct connexion with those in Taiwan of China.China has no endemic genus of Meliaceae.All the species common to China and outside China are of tropical Asia distribution type, and so they are common in origin.The time of the origin of Meliaceae might be inferred in Upper Cretaecous.