The Hymenasplenium obliquissimum group contains the widespread H. obliquissimum and several geographically restricted species, including H. retusulum, H. wuliangshanense, H. latidens, H. changputungense, H. quercicola, H. szechuanense, H. furfuraceum, H. adiantifrons, and H. filipes. However, the taxonomy of this group is still unclear and needs to be revised because some entities were treated infraspecifically or as synonyms and the validation of some species still needs to be assessed. To formulate a natural classification and investigate the relationships in this group, we collected and stu...
