Abstract: Floral ontogeny is described in two species of genus Magnolia (Magnoliaceae), Magnolia albosericea Chun et C. Tsoong, and M. amoena Cheng, representing subgenus Magnolia and subgenus Yulania in Magnolia, by using scanning electron microscope (SEM). The sequence of initiation of floral organs is from proximal to distal. The three distinct outermost and middle organs are initiated in sequence, but ultimately form a single whorl, thus their ontogeny is consistent with a sepal interpretation. The last three tepals (petals) alternate with the preceding tepal whorl. The members of androecium and gynoecium arise spirally, although the androecium shows some intermediacy between a spiral and whorled arrangement. The carpel primordia initiate in group of four to five. The order of stamen initiation within each tier is not determined. The floral ontogeny is remarkably homogeneous between the subgenus Magnolia and subgenus Yulania that does not support the resuming of genus Yulania.（Author for correspondence.Tel: +86 (0)20 3725 2661; Fax: +86 (0)20 3725 2831; E-mail: xfx@scib.ac.cn）

Key words: floral ontogeny, Magnolia albosericea, Magnolia amoena, subgenus Magnolia, subgenus Yulania.