基于叶绿体trnL-F,rbcL序列和核核糖体ITS序列探讨蓼属（蓼科）头状蓼组的系统发育

选用叶绿体基因trnL-F，rbc-L序列和核核糖体ITS序列对蓼属头状蓼组的分类和系统发育进行了分析。以药用大黄为外类群，用最大简约法对3个片段的单独和联合矩阵分别构建系统发育树。结果表明，头状蓼组是一个较自然的类群，与春蓼组、刺蓼组和金线草属的亲缘关系较近；支持头状蓼组作为一组放在春蓼属，细茎蓼和蓝药蓼从头状蓼组转移至冰岛蓼属；不支持将刺蓼组并入头状蓼组；对于小叶蓼的系统学位置有待于进一步研究。

Phylogeny of Polygonum Sect.Cephalophilon(Polygonaceae) Inferred from the Chloroplast trnL-F,rbcL and Nuclear Ribosomal ITS Sequences

The phylogeny of Polygonum sect.Cephalophilon was analyzed using the chloroplast genes trnL-F,rbcL and nuclear ribosomal ITS sequences.Individual and combined analyses of three datasets were performed with maximum parsimony method and the gene trees were constructed with Rheum officinale as outgroup.The results show that Polygonum sect.Cephalophilon is a more natural group which is the most closely related to Polygonum sect.Persicaria,sect.Echinocaulon and the genus Antenoron.The results support to put Polygonum sect.Cephalophilon into the genus Persicaria as a section and transfer P.filicaule and P.cyanandrum from Polygonum sect.Cephalophilon to the genus Koenigia,do not support to attribute Polygonum sect.Echinocaulon to Polygonum sect.Cephalophilon.There is strong conflict regarding the systematic position of Polygonum delicatulum,which needs further studies.