[1] The genus is recognized in the Pteridophyte Phylogeny Group classification of 2016 (PPG I),[2] but not by some other sources, which keep it in a broadly defined Huperzia.

A phylogenetic study in 2016, employing both molecular and morphological data, concluded that either a one-genus or a three-genus division of the subfamily produced monophyletic taxa.

The authors preferred the three-genus division, recognizing Huperzia, Phlegmariurus and Phylloglossum.

[4] However, the genera are difficult to separate morphologically, and others have preferred the one-genus division of the subfamily.

[1] As of June 2024[update], the Checklist of Ferns and Lycophytes of the World accepted over 300 species:[1] One hybrid is known:[1]