Integrative taxonomy successfully resolves the pseudo-cryptic complex of the disjunct epiphytic moss Orthotrichum consimile s.l. (Orthotrichaceae)

Broad morphological variation and a complex taxonomic history suggest that Orthotrichum consimile, an epiphytic moss known from oceanic forests of western North America and western Europe, may be a complex of cryptic species rather than a single taxon. This hypothesis was tested through an integrative taxonomic approach combining morphological investigations and phylogenetic inferences from four chloroplast loci. We show that O. consimile is in fact a polyphyletic assemblage of four lineages, which can be diagnosed unambiguously on morphological characters. They are Orthotrichum consimile s.str., O. columbicum (resurrected from synonymy), O. persimile sp. nov. and O. confusum sp. nov. Except for O. columbicum, which has a trans-Atlantic distribution, these species are endemic to western North America. Phylogenetic inferences increasingly resolve cases of so-called cryptic speciation within bryophytes exhibiting broad geographic distributions. Almost invariably the hypothesis of cryptic differentiation remains untested. Here we show that parallel morphological and phylogenetic inferences can lead to the resolution of apparent incongruence and lead to the discovery of new, morphologically defined, species.