半羽耳蕨亚属 ban yu er jue ya shu

Basionym: Polystichum sect. Haplopolystichum Tagawa, Acta Phytotax. Geobot. 9: 122. 1940.

Plants evergreen. Lamina 1-pinnate; if lamina bipinnatifid to tetrapinnatifid then pinnae finely dissected or rachis scales dark brown, ovate, and appressed; venation free or rarely anastomosing to form 1 or 2 rows of areoles.

Possibly around 270 species: the highest diversity in limestone areas in S China and dozens of species in the neighboring Himalaya (six species), Japan (11 species), Korea (four species), Myanmar (six species), Philippines (two species), Russian Far East (two species), Thailand (three species), and Vietnam (ca. 40 species); 88 species (70 endemic) in nine sections in China.

Polystichum subg. Haplopolystichum, corresponding to the so-called BCPC (Lu et al., Syst. Bot. 32: 26-33. 2007) or CCPC clade (Li et al., J. Plant Res. 121:19-26. 2008), or P. sect. Haplopolystichum Tagawa s.l. (Zhang & He, Bot. Stud. (Taipei) 50: 101-106. 2009), is one of the two subgenera of Polystichum.