摘要：对芍药属牡丹组Paeonia L. sect. Moutan DC.(全部野生种)40个居群进行了基于形态学证据的系统学分析,试图建立组内种间的系统发育关系.利用PAUP计算机程序分别构建了建立在25个形态学性状基础上的所有研究类群的距离树(UPGMA、NJ)和最大简约树(MP).所得树的拓扑结构基本一致,差异只发生在距离树和简约树之间,在由形态和细胞学关系都很近的5个种(牡丹P. suffruticosa、矮牡丹 P. jishanensis、卵叶牡丹P. qiui、紫斑牡丹P. rockii 和凤丹 P. ostii)构成的分支内部.在距离树(UPGMA和NJ)中,每个种的所有居群都首先形成1个单系类群,然后才与其他种的居群相聚.大花黄牡丹P. ludlowii、卵叶牡丹和四川牡丹 P. decomposita 3个种的单系类群得到大于90%的自展值支持,紫斑牡丹和滇牡丹P. delavayi 2个种的单系类群得到大于70%的自展值支持,牡丹、凤丹和矮牡丹3个种的单系类群得到51%-70% 的自展值的支持.在简约树(MP)中,上述所有种的自展支持值都小于距离树中的相应数值.同时牡丹、滇牡丹和凤丹的全部群体未能形成一个单系群.根据本文的研究结果, 分析讨论并首次提出了野生牡丹的系统发育关系.%Cladistic analysis of the morphological relationship of 40 populations of Paeonia sect. Moutan DC. (including all wild species) was carried out with an attempt to have a better understanding of the phylogeny of tree peonies. Twenty-five morphological characters were selected and used in unweighted pair-group method using arithmetic averages (UPGMA), the neighbor-joining (NJ) and the maximum parsimony (MP) tree construction executed with PAUP* program. The topologies of the trees obtained were largely in congruence and topological differences occurred only between MP tree and the other two in a clade comprising five species, P. suffruticosa, P. jishanensis, P. qiui, P. rockii and P. ostii, which were considered as closely related species based on both morphological and cytological characters. In both NJ and UPGMA trees, all the populations of each species formed a monophyletic clade, and the clades of P. ludlowii, P. qiui and P. decomposita had strong bootstrap supports (>90%), the clades of P. rockii, P. delavayi had moderate bootstrap supports (>70%), and the clades of P. suffruticosa, P. ostii and P. jishanensis had weak bootstrap supports (51%-70%). In MP tree, however, the corresponding bootstrap values of all the clades mentioned above were generally smaller than those in NJ and UPGMA trees and the populations of P. delavayi, P. ostii and P. suffruticosa failed to form monophyletic clades. Based on the above results, interspecific relationships of wild tree peonies were discussed and a phylogeny of sect. Moutan was reconstructed for the first time.