Abstract: The present paper deals with the karyotypes of Pinus yunnanensis Franch. and P. kesiya var. langbianensis (A.Chev.) Gaussen. The chromosomes of them are 2n=24, which all belong to metacentric one. There are three pairs of chromosomes (No. 2, 5, 8) with secondary constriction in P. yunnanensis Franch., and only one (No. 3) in P.kesiya var. langbianensis (A. Chev.) Gaussen and its first pair of chromosomes are heterozygous. The karyotype of P.kesiya var. langbianensis (A. Chev.) Gaussen is not as regular as that of P. yunnanensis Franch. By the comparison between their karyotypes, it is shown that the relationship between both of them is not close and P. kesiya var. langbianensis (A. chev) Gaussen is more advanced than P. yunnanensis Franch. in the evolution.

Key words: karyotype, pinus, Yunnanensis