The cosmopolitan family Orthotrichaceae comprise 27 genera arranged into to subfamilies. The Orthotrichoideae comprises primarily acrocarpous taxa distributed in temperate parts of the world , whereas the Macromitrioideae accommodates cladocarpous taxa centered in (sub-)tropical regions. Our taxon sampling encompasses much of the generic and subgeneric diversity within the family. Analyses of nucleotide sequences of the trnL-trnF region, the rps4 and rbcL genes supports this systematic concept. Chloroplast data also reveal a para- or polyphyletic nature of the large speciose genera Orthotrichum Zygodon and Macromitrium. Broadening the character sampling to the mitochondrial (nad5 gene) and the nuclear genome (portion of the LEAFY gene) are currently underway to test these hypotheses. These data will also aid in addressing the hypothesis inferred from morphological and chloroplast suggesting that the genus Bryomaltaea (Orthotrichoideae, Zygodonteae) is either of hybrid origin or represents the most basal lineage within the family.

Key words: Bryophyta, nad, Orthotrichaceae, phylogeny, rbcL, rps4, trnL