The Bryophyta (Mosses): Systematic and Evolutionary Inferences from an rps4 Gene (cpDNA) Phylogeny

Phylogenetic analyses of nucleotide and amino acid sequences of the chloroplast protein coding gene rps4 were performed for 225 species of mosses, representing 84% of families recognized by Vitt (1984. In: Schuster RM, ed. New manual of bryology , vol 2 . Nichinan: Hattori Botanical Laboratory), under the criterion of maximum parsimony with Takakia and Sphagnum as outgroups. Most parsimonious topologies converge to a scenario wherein the Andreaeidae are monophyletic and sister to the Bryidae (peristomate mosses), the Nematodonteae and the Buxbaumiaceae form a monophyletic lineage, the Diphysciaceae are sister to the Arthrodonteae and, within the latter, the Funarineae-Encalyptineae-Timmiaceae-Haplolepideae compose a monophyletic clade sister to remaining diplolepideous mosses. This hypothesis suggests that early in the evolution of the Arthrodonteae, two major lineages diverged, with opposite and alternate peristomes, respectively. Bootstrap support for the deep dichotomies is poor or lacking but increases when protein translations of rps 4 sequences are included in the analysis. Several novel systematic hypotheses are raised, including ( a ) a diplolepideous rather than haplolepideous origin of the Pleurophascaceae; ( b ) an affinity of the Catascopiaceae with the Funariineae rather than the Bryineae; and ( c ) a close relationship of the Calomniaceae and Mitteniaceae to the Rhizgoniaceae. The advantages and disadvantages of a single gene phylogeny are discussed with respect to the identification of polyphyletic familial or suprafamilial taxa.