Molecular phylogeny of Trichostomoideae (Pottiaceae, Bryophyta) based on nrITS sequence data

Bayesian analysis of an alignment of 83 nrITS sequences belonging to 66 taxa of Pottiaceae revealed representatives of subfamily Trichostomoideae in a well supported monophyletic lineage. Two robust clades within Trichostomoideae include species of Tortella and Weissia, respectively. Eucladium verticillatum is part of Trichostomoideae, and Anoectangium, Gymnostomum, Hymenostylium, and Tuerckheimia form a robust basal clade. Affinities of Hyophila and Leptobarbula to Trichostomoideae are unclear. Within Trichostomoideae, Pleurochaete squarrosa is resolved in Tortella while Trichostomum tenuirostris, Pseudosymblepharis, and Chionoloma are placed as a separate genus or part of a broadly defined Tortella. The type species of Trichostomum, T brachydontium, is nested in Weissia together with T brillonianum, T crispulum, and T jamaicensis. Trichostomum unguiculatum and W. ayresii are resolved as closely related and separate from the rest of the Weissia clade. The genus Astomum, erected for cleistocarpous species of Weissia, is also nested within Weissia. Genetic divergence between selected accessions of Weissia controversa and Astomum is sometimes smaller than between accessions of Weissia controversa.