Data from: The supposedly well-known carbonate indicator Tortella tortuosa (Pottiaceae, Bryophyta) split into eight species in Europe

We present a first treatment of the Tortella tortuosa complex for Europe.
We analysed molecular relationships based on the nuclear ITS and the
plastid atpB-rbcL and rps4 in a network context and thereafter
characterized the identified entities by their morphology. We found eight
morphologically and molecularly distinct entities at the species level,
which are also supported in ASAP analyses of the molecular data; one
species includes two varieties. In some cases, nuclear and plastid data
suggest different relationships and we found a few likely recent hybrid
collections. To the main characters of taxonomic importance belong stem
anatomy, leaf shape and papillosity. We describe three species as new: T.
commutata (a widespread plant; including the new var. valida), T.
dolomitica (known only from the Alps) and T. splendida (an Arctic-alpine
element), replacing T. arctica auct. For T. angustifolia and T. robusta
(both montane) new combinations at the species level are provided.
Tortella bambergeri (a submediterranean element), T. fleischeri (an Alpine
element, recurring in Scotland) and T. tortuosa s. str. (widespread)
complete this informal group of morphologically similar and partly related
species. The species differ in ecological requirements and distribution
areas, although mixed stands of two or three species are frequent. The
area richest in species in Europe is the Alps with all eight species,
whereas we found only four from Scandinavia.