Abstract: Amphicarpaea edgeworthii Benth. is an amphicarpic legume widespread in China， of which three types of flowers can be produced in the same individual： aerial chasmogamous flowers， aerial cleistogamous flowers， and subterranean cleistogamous flowers. The morphological and embryological characteristics of aerial and subterranean flowers were examined by light and scanning electronic microscopes. The anther of aerial chasmogamous flowers was 4-sporangiate， and of Glandular tapetum. Cytokinesis of microspore mother cells in meiosis was of the Successive type， and tetrads were tetradedral. The mature pollen grains were 2-celled. The ovule was biteguminous and crassinucellate. The development of embryo sac was of the Polygonum type. The embryogeny was of the Onagrad type， and endosperm development corresponded to the Nuclear type. The embryological characteristics of the subterranean flowers were quite similar to those of aerial chasmogamous flowers. The main differences from the latter were： the anther was 2-sporangiate； the meiosis of microspore mother cells was accompanied by the Simultaneous and Successive types， and tetrads were tetrahedral and isobilateral. Meanwhile， embryological data available in Papilionoideae plants were analyzed， and the phylogenetic position of A.edgeworthii was discussed.

Key words: Amphicarpaea edgeworthii Benth., Leguminosae, chasmogamous flowers, cleistogamous flowers, embryology

摘要： 两型豆同一植株上同时产生3种类型的花，即地上开放花、地上闭锁花和地下闭锁花。它们分别发育成熟于地上和地下。利用常规的石蜡切片和扫描电镜技术对地上和地下花的形态及胚胎学过程进行了研究。结果表明：1)地上开放花的花药4室，绒毡层为腺质型，小孢子四分体四面体型，胞质分裂同时型，二细胞型花粉，胚珠弯生，双珠被，厚珠心，胚囊发育为单孢蓼型，胚发育为柳叶菜型，核型胚乳；2)地下花的胚胎学特征与地上花基本相同，主要差异表现在花药2室，小孢子四分体以四面体型为主（可见左右对称型），胞质分裂同时型与连续型共存。同时，结合已有资料，对豆科蝶形花亚科植物的胚胎学特征进行了比较分析，探讨了两型豆属植物的系统位置。

关键词: 两型豆, 豆科, 开放花, 闭锁花, 胚胎学