XVI International Botanical Congess

In molecule-based phylogenies of basal embryophytes, three conflicting hypotheses have emerged. In one, liverworts are the basal group of embryophytes and are monophyletic, in a second, liverworts are basal, but polyphyletic, and in a third, hornworts are basal and liverworts are sister to the mosses. None of these hypotheses are strongly supported, although the first is congruent with morphological evidence. To resolve these conflicts, sequence data for the rbcL, 18S rRNA and nad5 genes have been combined with morphological data scored for 69 characters in a total evidence analysis of these groups. The results of this analysis will be evaluated against the above hypotheses and evolutionary trends and within group relationships will be discussed.