CpDNA-relationship and classification of the liverworts (Hepaticophytina, Bryophyta)
Stech, Michael; Frey, Wolfgang
Partial cpDNA trnLUAA intron sequences of 48 bryophyte species (including 33 species of Jungermanniopsida), two eusporangiate ferns and Chlorella spec. are compared. In maximum parsimony trees, the liverworts (Hepaticophytina) are monophyletic and divided into four clades, which are distinguished as classes: Treubiopsida, Marchantiopsida, Blasiopsida class. nov. and Jungermanniopsida. Due to the variability and amount of homoplasy in the trnLUAA intron, no significant bootstrap support is achieved for the clades of the classes (except for the Treubiopsida) when a large number of liverworts is included. Within bryophytes, the highest sequence variability is observed in the Jungermanniopsida, indicating a higher substitution rate or the existence of long separated, only distantly related taxa. Relationships within the Jungermanniopsida are only partly resolved. The thallose/semileafy Metzgeriidae are monophyletic without bootstrap support, whereas the leafy Jungermanniidae appear as polyphyletic. Haplomitrium (Calobryales) does not occupy a basal position within the Jungermanniopsida, but belongs to the Metzgeriidae cluster.