单性木兰（木兰科）花的形态发生

报道了单性木兰(Kmeria septentrionalis Dandy)花的形态发生过程。发现过去一直被认为是雌花条状披针形的“内轮花被片”，实际为退化雄蕊，它形态发生的时间与位置均与雄花的雄蕊相同，在成熟结构中仍可见药室残迹，说明单性木兰的雌性花是由两性花退化而来。通过与K. duperreana(Pierre) Dandy和Magnolia thailandica Noot. &; Chalermglin雌花的比较，发现它们雌花的形态相同，从而得知人们长期以来对此3种植物雌花的认识有误，原一直认为的“内轮花被片”实为退化雄蕊。

Floral Organogenesis of Kmeria septentrionalis (Magnoliaceae)

The floral development of Kmeria septentrionalis Dandy(Magnoliaceae) is reported for the first time using scanning electron microscope. The so-called linear-lanceolate inner tepals in pistillate flowers are actually staminodes whose initial time and ontogenetic positions are the same as those of the stamens in staminate flowers. In addition, a few vestigial anther cells, remained in some matured staminodes, indicate that the pistillate flower of K. septentrionalis is evolved from the bisexual flower. The pistillate floral morphology of K. septentrionalis is found similar to those of K. duperreana(Pierre) Dandy and Magnolia thailandica Noot. & Chalermglin, therefore, the structures between tepals and pistils are staminodes in pistillate flowers of the three species.