Niphobolus nudus Giesenhagen, Niphobolus, 149. 1901; Cyclophorus nudus (Giesenhagen) C. Christensen.

Plants 10-20 cm tall. Rhizome long creeping, 1.2-2.1 mm in diam., in cross section usually with a single, central sclerenchyma strand; phyllopodia 1-2 cm apart, lateral buds alternating with phyllopodia. Scales peltate, 3.9-7.8 × 0.3-1.3 mm, base entire to ciliate; acumen light brown, often with a distinct hyaline margin, ciliate; short, orbicular to ovate scales usually present. Fronds subdimorphic. Stipes 1-4 cm; lamina widest below or at middle, 10-25 × 1-1.8 cm, base attenuate, decurrent, apex long caudate. Fertile fronds narrower. Hydathodes rarely present, few and indistinct. Indument monomorphic, sparse, whitish to brown; hairs 0.2-1.2 mm with erect-spreading to appressed, boat-shaped to ± acicular rays. Sori sunken, with a distinct central bundle of stellate paraphyses. Sporangia with stalks 1.5-2 × as long as capsule.

On tree trunks in forests; 500-1500 m. Hainan, Sichuan, Yunnan [Bhutan, N India, Myanmar, Nepal].