As a result of several coordinated projects, rbcL sequences from nearly all hypnobryalean families have been obtained and compiled. Our goal was to investigate what a large data matrix of rbcL sequences can tell us about the relationships within the pleurocarps, what groups of taxa are supported by this sequence, and how well the rbcL sequence resolves the relationships between the groups. Cladistic analyses of this sequence divide the pleurocarps into three primary clades: Hookeriales A, Hookeriales B, and Hypnales sensu lato, which includes the Leucodontales. The strict consensus shows good resolution within groups of families, but not among the groups. Robust clades of families revealed by the present analyses include the following: [Leucodontaceae, Climaciaceae, Anomodontaceae], [Neckeraceae, Leptodontaceae, Echinodiaceae, Lembophyllaceae], and [Hypnaceae, Thuidiaceae, Entodontaceae, Sematophyllaceae]. The general tree topology is not congruent with previous hypotheses of relationships among suborders and superfamilies in the traditional Leucodontales and Hypnales. The phylogeny of the pleurocarps is not as yet resolved, but this study shows that the current classification of three suborders in the Hypnales and four in the Leucodontales, is no longer tenable.

Key words: Hypnales, Mosses, pleurocarps, rbcL.