关键词: 八角莲, 大孢子, 雌配子体

Abstract: The present paper firstly reports the megasporogenesis and the formation of female gametophyte in Dysosma versipellis(Hance) M.cheng.Result shows thot:The ovule is bitegminous,Most are crassinucellate and amphitropous,but sometimes are pseudocrassinucellate and campylotropous.The ovary is unilocular with many ovules.The placentation is marginal placenta.The micropyle is formed by both the inner and the outer integuments.The female archesporium is hypodermal and single-celled,sometimes appear two or three archesporial cells.The two type in the development of megaspore mother cell.The megaspore mother cell goes meiosis to form a linear tetrad.The chalazal megaspore is functional.The development of the embryo sac conforms to the Polygonum type.In mature embryo sac,two polar nucleus fused into the secondary nucleus before fertilization;three antipodal cells are ephemeral;the triangular egg apparatus is obvious polarity,the polarity of egg cell and synergids is opposite;two synergids are developed,the morpha and size of its fifiform apparatus are different in the development of the embryo sac,and it functions as a haustrum.

Key words: Dysosma versipellis(Hance) M.cheng., megaspore, female gametophyte