Patterns of relationships in Trichostomoideae (Pottiaceae, Musci).

Ribosomal DNA sequences were employed to infer relationships among European Pottiaceae. Intragenic spacer I was sequenced for six Trichostomoideae (Eucladium verticillatum, Pleurochaete squarrosa, Tortella flavovirens, T. nitida, T. tortuosa, Trichostomum brachydontium) and seven taxa from the other European subfamilies included in Pottiaceae (Bryoerythrophyllum recurvirostrum, Didymodon vinealis, Microbryum starkeanum, Tortula muralis, Syntrichia ruralis, Weissia controversa and Timmiella cf. barbuloides). Cladistic analysis of sequence data shows close relationships between Pleurochaete, Tortella and Weissia. Tortella appears to be paraphyletic, as it includes Pleurochaete, Weissia and Trichostomum. Weissia, therefore, seems to be better placed in Trichostomoideae than, as traditionally done, in Pottioideae. Neither Merceyoideae nor Pottioideae appear to be monophyletic sensu stricto, at least within the limits of the taxa in analysis. Within the latter subfamily, Syntrichia is clearly separated from Tortula. These results would suggest that taxonomy in Pottiaceae does not depict the pattern of descent, and therefore is in need of revision.