Another Fennoscandian Tortella species with fragile leaves, Tortella fragmenta (Pottiaceae, Bryophyta)

The well-known limestone species Tortella fragilis consists of two species, which are clearly circumscribed by the nuclear molecular marker ITS, and the plastid atpB-rbcL and rps4. The morphological differences between the two are relatively small. Because all specimens cannot be identified with certainty they could be understood as semi-cryptic. The two differ in the orientation of dry leaves and the appearance of papillae on lamina cells in mid-leaf. Dry leaves of T. fragilis s.str. are often screwed or slightly so, and near the shoot apex numerous leaves are sometimes tightly adhering (or parallel) to each other and together slightly screwed, or sometimes more loosely so or somewhat curled, and the lamina cells are densely papillose with papillae that are difficult to distinguish individually and obscure the cell walls. In T. fragmenta, which is described as new, the leaves are at most slightly screwed, curled, also near shoot apex, and not or hardly adhering to each other, and the l..., For the molecular part of this study, 24 specimens of Tortella fragilis s.l. from Fennoscandia were sequenced and sequences for two additional specimens, from Greenland and Gorno-Altai in Russia, were downloaded from GenBank. Based on Hedenäs (2015), Köckinger and Hedenäs (2017), Köckinger, et al. (2018), and (Köckinger and Hedenäs 2023), 53 specimens belonging to 15 other Tortella species, two specimens of Chionoloma tenuirostre, and two of Trichostomum crispulum Bruch were selected as outgroup.
The nuclear internal transcribed spacers 1 and 2 (ITS) and the plastid atpB-rbcL spacer (atpB-rbcL) and the rps4 gene + trnS-rps4 spacer (rps4) were studied. DNA was extraction and new sequences were generated as described by Hedenäs (2015; https://doi.org/10.1007/s00606-014-1159-9).
Nucleotide sequence fragments were edited and assembled for each DNA region using PhyDE® 0.9971 (http://www.phyde.de/index.html; accessed 7 March 2024). In the final data set, all three sequences were availabl..., , # Data from: Another Fennoscandian Tortella species with fragile leaves, Tortella fragmenta (Pottiaceae, Bryophyta)

[https://doi.org/10.5061/dryad.3tx95x6ps](https://doi.org/10.5061/dryad.3tx95x6ps)

## Description of the data and file structure

*The uploaded files are sequence alignments for ITS, atpB-rbcL, and rps4.*

Twenty-six Tortella fragilis (Drumm.) Limpr. s.l. specimens were studied molecularly, including two specimens which sequences were downloaded from GenBank (see Appendix 1 of the paper). Based on Hedenäs (2015), Köckinger & Hedenäs (2017), Köckinger, et al. (2018), and Köckinger & Hedenäs (2023), 53 specimens belonging to 15 other Tortella species (Appendix 1 of the paper), two specimens of Chionoloma tenuirostre (Hook. & Taylor) M. Alonso, M.J. Cano & J.A. Jiménez, and two of Trichostomum crispulum Bruch were selected as outgroup.

The nuclear internal transcribed spacers 1 and 2 (ITS) and the plastid atpB-rbcL spacer (atpB-rbcL) and the rps4 gene + trnS-rps4 spacer (r...,