Athyrium Roth. Lady Fern.
A genus of about 225 species, cosmopolitan in distribution, but concentrated in e. and se. Asia. Wei et al. (2017) recognize ten sections in the genus; the species in our area are in section Athyrium. For our area, Kelloff et al. (2002) and Kelloff & Werth (1998) support recognition of two taxa at either specific or infraspecific levels, based on morphology, allozymes, and spores.
ID notes: Athyrium and Deparia superficially resemble Dryopteris, and they often grow together. Athyrium and Deparia have linear, flap-like sori (vs. rounded, reniform sori). Sterile individuals can be distinguished by the number of vascular bundles in the petiole (easily determined by breaking off a leaf and counting the vascular bundles, which will appear as thread-like, but flattened, strands); Athyrium and Deparia have 2, Dryopteris has 4-7.
Ref: Kato (1993c) In Flora of North America Editorial Committee (1993b); Kelloff et al. (2002); Kramer & Green (1990); Moran, Hanks, & Sundue (2019); Wang, He, & Kato in FoC (2013); Wei et al. (2017). Show full citations.