The Lewinskya affinis complex (Orthotrichaceae) revisited: species description and differentiation

In a recent integrative taxonomy study, we verified that the previously accepted concept of Lewinskya affinis (≡ Orthotrichum affine) actually comprises a complex of sibling lineages encompassing both known, accepted species (L. affinis s.str., L. praemorsa and L. tortidontia), recovered synonyms (L. fastigiata and L. leptocarpa), and four species yet unpublished. In the present work, we present detailed descriptions of the previously identified species and the new species, L. scissa from the Canary Islands, and the North American L. arida, L. pacifica and L. pseudoaffinis. In addition, we provide a key to the species in the complex, and discuss the morphological distinction of the species according to geographical areas. All included species are illustrated.