Integration of morphological and ribosomal RNA data on the origin of angiosperms

Previous phylogenetic analyses of morphological and rRNA data indicated that Gnetales are the closest living relatives of angiosperms but gave different basal angiosperm relationships. A two-step morphological analysis of seed plants (including fossils) and angiosperms rooted the latter near Magnoliales, with tricolpate eudicots and paleoherbs (herbaceous magnoliids and monocots) forming a clade, whereas analyses of rRNA sequences rooted angiosperms among paleoherbs, with eudicots and woody magnoliids forming a clade. Experiments with a revised seed plant morphological data set raise further questions: when angiosperms are scored like different angiosperm subgroups, they associate with different outgroups, although Gnetales are their closest living relatives