The Didymodon tophaceus complex (Pottiaceae, Bryophyta) revisited: new data support the subspecific rank of currently recognized species
Abstract
Additional samples of Didymodon erosus and D. sicculus, barcoded using ITS sequences, necessitated the broadening of the morphological concepts and the reported ecology of these taxa, both of which were revealed to have considerable overlap. Additional molecular data from the chloroplast genome confirmed the earlier published phylogenetic inference based on the nuclear ITS, which groups Didymodon tophaceus, Didymodon erosus and D. sicculus into a highly supported lineage of closely related taxa.
In view of the morphological overlap among taxa of the D. tophaceus complex, supported by the ITS non-monophyly of D. tophaceus in its current morphological concept, we advocate the reduction of D. erosus and D. sicculus to infraspecific rank within D. tophaceus. Sporophytes are described for the first time in D. erosus, and new country records for the latter two taxa are reported.