Steiropteris (C.Chr.) Pic.Serm., Webbia

Smith, Alan R. & Kessler, Michael, 2017, Prodromus of a fern flora for Bolivia. XXX. Thelypteridaceae, Phytotaxa 331 (1), pp. 1-34 : 29

Steiropteris (C.Chr.) Pic.Serm., Webbia 28: 449. 1973.

= Thelypteris Schmidel subg. Steiropteris (C.Chr.) K.Iwats., Mem. Coll. Sci. Kyoto Imp. Univ., Ser. B, Biol. 31: 31. 1964.

= Thelypteris sect. Steiropteris (C.Chr.) C.V.Morton, Amer. Fern J. 53(4): 153. 1963.

= Glaphyropteris C.Presl ex Fée, Crypt. Vasc. Brésil 2: 40. 1873.

= Thelypteris subg. Glaphyropteris (C.Presl ex Fée) Alston, J. Wash. Acad. Sci. 48: 234. 1958.

Steiropteris is monophyletic and sister to all remaining cyclosoroid genera ( Almeida et al., 2016). Some species may be easily confused with species of Goniopteris . The genus is entirely neotropical, with ca. 22 species, six in Bolivia, and several of these with varietal variation ( Smith 1980). Two aberrant species from southern Brazil, S. polypodioides (Raddi) Salino & T.E.Almeida and S. villosa (Link) Salino & T.E.Almeida (previously incertae sedis), have recently been found to nest in Steiropteris ( Almeida et al. 2016) .

Steiropteris is generally characterized by 1-pinnate-pinnatifid blades without gradually reduced proximal pinnae, a cartilaginous keel or minutely pubescent false vein running from each sinus towards the costae (lacking in S. decussata and related species), true veins running to sinuses, or anastomosing at acute angles below sinuses, indusia persistent or absent, and usually (except S. gardneriana , S. glabra , S. parva ) by pale (often dark when dried), peglike or scalelike aerophores at the pinna bases; and a chromosome base number of x = 36. Two fairly well defined subgroups are often recognized, subg. Steiropteris , comprising most of the species, and subg. Glaphyropteris (C.Presl ex Fée) A.R.Sm., comprising S. decussata and allies ( Smith 1980).