Differentiation In Dna Fingerprinting And Morphology Among Species Of The Pleurocarpous Moss Genus, Rhytidiadelphus (Hylocomiaceae)

DNA fingerprinting techniques including inter simple sequence repeats (ISSR) and restriction digest patterns from 18S-26S nuclear ribosomal DNA internal transcribed spacers (ITS) were combined with a detailed morphological analysis to seek characters that discriminate closely related species in the pleurocarpous moss genus, Rhytidiadelphus. The two sibling species, R. subpinnatus and R. squarrosus, were indistinguishable based on ITS markers but displayed a clear genetic discontinuity based on ISSR markers. Overall, genetic divergence was similar among R. squarrosus and R. subpinnatus on the one hand and R. loreus and R. triquetrus on the other. The results clearly support the specific status of R. subpinnatus and R. japonicus within the controversial R. squarrosus complex. New divergent morphological characters were found between R. subpinnatus and R. squarrosus. The results suggest that ISSR markers may be an alternative for distinguishing sibling moss species when sequences of the most variable genomic regions traditionally used at low taxonomic level, Such as ITS, do not provide the appropriate degree of polymorphism.