Cryptic speciation in Herbertus (Herbertaceae, Jungermanniopsida):: Range and morphology of Herbertus sendtneri inferred from nrITS sequences

Maximum likelihood and parsimony analyses of nrITS1-5.8S-ITS2 sequences place Austrian Herbertus sendtneri in a well bootstrap supported clade with Herbertus azoricus and Neotropical accessions which were alternatively assigned to Herbertus subdentatus or Herbertus dicranus. Asian and African Herbertus dicranus form a separate lineage which is placed sister to several European Herbertus taxa. Herbertus borealis from the British Isles is placed sister to H. stramineus in a robust sister relationship, indicating that the species does not belong in the synonymy of H. dicranus. As a result of the molecular investigation, the range of Herbertus sendtneri is extended to the Neotropics and H. azoricus is placed into the synonymy of H. sendtneri. Without much doubt, Herbertus dicranus does not occur in tropical America. Morphologically, H. sendtneri and H. dicranus can at most be separated by weak tendencies. Herbertus sendtneri is characterized by the frequent occurrence of coarse appendages at the leaf margins and often completely papillose leaves. H. dicranus often has small appendages and a nearly smooth basal leaf half. Herbertus borealis, which is nonmonophyletic with H. dicranus in the molecular trees, cannot be separated morphologically from forms of H. dicranus with small appendages. Herbertus subdentatus is not identical with H. sendtneri. Morphological homoplasy and cryptic speciation are obviously common in Herbertus.