Molecular, morphological and taxonomic evaluation of the Ptychanthus striatus (Lejeuneaceae, Marchantiophyta) complex

The internal phylogeny and cryptic species of the taxon known as Ptychanthus striatus (Lehm. et Lindenb.) Nees were investigated using morphology as well as phylogenetic studies based on internal transcribed spacer II (ITS2) sequences. Both parsimony analysis and analysis based on Bayesian inference were performed. They both distinguished the African specimens from the Asian-Oceanian specimens, but resolved the specimens differently within these groups. Different alignment methods were compared, and the implied alignment obtained from the direct optimisation by program POY was found to produce a shorter tree in parsimony analysis than the DiAlign or manually improved Clustal alignments. Based on oil body characters and molecular evidence, the African population of Ptychanthus can be distinguished from the Asian-Oceanian one at the species level. The earliest applicable name for the African taxon is Ptychanthus africanus Steph.