Publication: Amer. J. Sci. Arts. ser. 2, 22: 138. 1856.
selected vouchers: WTU
Notes: FNA2: "Polypodium glycyrrhiza hybridizes with P . calirhiza and with P . hesperium to produce sterile triploids with misshapen spores. Polypodium glycyrrhiza was involved in the origin of both of these allotetraploid species, and some individuals can be difficult to identify. Free versus anastomosing venation distinguishes this species from P . calirhiza ; the presence of adaxial hairs on the rachis separates it from P . hesperium . An additional character for distinguishing these taxa is spore length, which is less than 58 Âµm in diploid P . glycyrrhiza and more than 58 Âµm in the two tetraploid species."