Evolutionary Biology, U-3043,

Ordinal relationships of pleurocarpous mosses, with special emphasis on the Hookeriales Abstract Sequence data from four DNA regions, namely, chloroplast trnL–trnF and rps4, mitochondrial nad5, and nuclear 26S rDNA, were surveyed from 89 taxa tradi-tionally associated with the Hookeriales, five Hypnales and five outgroups. Phylo-genetic reconstruction was performed using the maximum parsimony andmaximum likelihood optimality criteria and by Bayesian phylogenetic inference. Thirteen mor-phological characters were optimized on the resulting phylogeny using maximum likelihood. Inferences of character evolution based on the molecular phylogeny sug-gest that (1) the core of pleurocarpous mosses (i.e. the Hypnanae) is best defined and thus distinguished from the Ptychomnianae by smooth rather than furrowed capsules, (2) a synapomorphy for the Ptychomnianae is the short and double (or absent) costa and (3) the Hookeriales are defined by undifferentiated alar cells. The Ptychomniaceae plus Garovagliaceae are recognized as a single family in its ow