1. Themelium blechnifrons (Hayata) Parris, Kew Bull. 59: 224. 2004.
蒿蕨 hao jue
Polypodium decrescens Christ var. blechnifrons Hayata, Icon. Pl. Formosan. 4: 245. 1914; Cryptosorus decrescens (Christ) Nakai ex H. Itô var. blechnifrons (Hayata) Nakai ex H. Itô.
Stipe 0.3-2.3 cm, sometimes subarticulate, with dense solitary simple medium to dark reddish brown hairs up to 2 mm. Lamina deeply pinnately divided to narrow wing along rachis, narrowly elliptic, 5-21 × 1.2-5 cm, gradually or rather abruptly shortened to form a wavy or crenate wing to base, apex acuminate or acute; pinnae inclined or widely ascending; middle pinnae largest or nearly so, linear to linear-lanceolate, 7-28 × 2-5 mm, dilated at base, entire, sometimes slightly undulate; rachis brown to dark brown, distinctly prominent on abaxial surface, variable (plane, slightly prominent, or grooved) on adaxial surface; costae hidden and invisible; veins hidden, but visible with transmitted light in younger fronds, simple; hairs confined to basal part of lamina, or to very young laminae, similar to those of stipe, up to 1.5 mm, occasional to scattered on abaxial side of rachis and sometimes on margins, occasional to sparse on adaxial side of rachis and both sides of lamina adjacent to rachis. Sori orbicular, oval, or oblong, slightly sunken in shallow depressions, in a medial row on each side of costa.
On moss-covered tree trunks and moss-covered rocks, terrestrial on steep slopes, in dense mountain forests; 500-2300 m. Taiwan [Philippines].
Material of this species has been misidentified as Ctenopteris curtisii (Baker) Copeland (e.g., FRPS 6(2): 308. 2000).