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Dryad

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

Data files

Apr 03, 2025 version files 191.41 KB

Abstract

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 lamina cells are moderately densely papillose with distinct and sometimes forked papillae that do not obscure the cell walls. Tortella fragilis is widespread in Fennoscandia, whereas T. fragmenta occurs primarily in the mountain range, with scattered occurrences in the lowlands of the boreal zone. Both species occur in calcareous or base-rich sites, with a tendency for T. fragilis to grow in wetter sites than T. fragmenta.