Description from Flora of China
Niphobolus tonkinensis Giesenhagen, Niphobolus, 144. 1901; Cyclophorus tonkinensis (Giesenhagen) C. Christensen; Pyrrosia porosa (C. Presl) Hovenkamp var. tonkinensis (Giesenhagen) Hovenkamp.
Plants 10-40 cm tall. Rhizome shortly elongated, 1.6-3.1 mm in diam., in cross section with few to many sclerenchyma strands; phyllopodia 0.3-0.7 cm apart, lateral buds alternating with phyllopodia. Scales peltate 3.6-6.2 × 0.5-1.3 mm, base entire to dentate; acumen light brown, dentate. Fronds monomorphic, sessile or indistinctly stipitate; lamina widest above middle, 8-22 × 0.5-1 cm, base gradually narrowed, apex acute to acuminate. Hydathodes distinct, superficial. Indument persistent, dimorphic, dense, brown or lower layer whitish; hairs 0.2-0.8 mm in diam., with acicular rays appressed to a layer with mainly woolly rays. Sori superficial, without central bundle of paraphyses. Sporangia with stalks 0.5-1 × as long as capsule.
On tree trunks or rocks in forests; near sea level to 1600 m. Guangdong, Guangxi, Guizhou, Hainan, Yunnan [Laos, Thailand, Vietnam].