XVI International Botanical Congess
The mitochondrial genes nad2 and nad5 have been used to establish phylogenies of bryophytes and pteridophytes. The trees support monophylies of true ferns, leptosporangiate ferns, mosses, liverworts (with Jungermanniidae and Marchantiidae as sister groups), a close branching of tree and water ferns and the inclusion of Psilotum among eusporangiates. Positionally conserved intron sequences add phylogenetic information. Statistical support increases with fusion of nad2 and nad5. Two superorders proposed earlier (Hypnanae, Dicranane) require modification and some classically defined orders are rejected as not monophyletic (Neckerales, Dicranales). Sphagnales, Andreaeales, Polytrichales and Tetraphidales are set apart form a subclass Bryidae with Buxbaumiales as mediating taxon.