Abstract: This paper analyses the karyotypes of 12 species of Magnolia in China. x= 19. M. offcinalis, M. theinalis subsp. biloba, M. sp., M. delavayi, M. amoena and M. coco of them are diploid species, 2n=2x= 38; M. liliflora, M. denudata and M. biondii are tetraploid species, 2n= 4x= 76; M. lotungensis, M. grandiflora and M. grandthera var. lanceolota are hexaploid spe- cies, 2n=6x=114. The polyploidy (secondary polyploidy) exists in Magnolia. The result of karyotype analysis showes that the karyotype differences among species in Magnolla are very small. Most of chromosomes are metacentric (m) A few of them are submetacentric (sm). The diploid species have only a pair of acrocentric chromosome (st). All of them are 2B type.

Key words: Magnoliaceae

摘要： 对我国木兰属（Magnolia）12个种的核型进行了分析，x=19，厚朴、凹叶厚朴、红花山玉兰、山玉兰、天目木兰、夜合为二倍体，2n=2x=38；紫玉兰、玉兰、玉堂春为四倍体，2n=4x=76；乐东木兰、荷花玉兰、狭叶荷花玉兰为六倍体，2n=6x=114，该属具有属内多倍体（次生多倍化）。核型分析结果表明：木兰属种间核型差异较小，大部分为中部着丝粒染色体（m），少数为具近中部着丝粒染色体（sm），二倍体种中只有一对具近端部着丝粒染色体(st)，其核型均为 2B型。

关键词: 木兰科, 木兰属, 核型分析