Plantago (Plantaginaceae) is a genus of more than 200 annual and perennial herbs and semi-shrubs with a worldwide distribution. The genus is considered monophyletic, but some of the infrageneric relationships are ambiguous. The first molecular phylogeny at the genus level is presented. About 60 representative species from the 24 series, as defined by Rahn (1996) were sequenced for nuclear ITS and chloroplast trnL regions. The phylogenetic analysis is correlated with Rahns morphological phylogeny from 1996, and with known iridoid glucoside patterns, but subgenus Albicans is paraphyletic. Five monophyletic subgenera are recognised, Plantago, Coronopus, Psyllium, Littorella and Bougeria. Littorella is sister to the other subgenera of Plantago. Series Hymenopsyllium is surprisingly closer related to section Gnaphaloides than to section Albicans. Only part of the sections can be resolved into series. The DNA variation within subgenus Plantago is low, as also expected from morphology.

Key words: iridoid glucosides, ITS, molecular phylogeny, Plantago, trnL