Abstract:Chromosome numbers of five species and one hybrid （Michelia sirindhorniae （Noot. ＆ P. Chalermglin） N. H. Xia et X. H. Zhang, comb. nov., Michelia sphaerantha C. Y. Wu ex Law et Y. F. Wu, Michelia doltsopa Buch. -Ham ex DC., Michelia coriacea Chang et B.L. Chen, Manglietia garrettii Craib, Michelia maudiae Dunn x Michelia macclurei var. sublanea Dandy） of Magnoliaceae were observed. The results indicated that they have the same basic number of chromosome （x=19）, and that they are diploids （2n=38）. Chromosome numbers of all taxa except Michelia doltsopa are reported for the first time.
