Antrophyum annamense Tardieu & C. Christensen.

Rhizome short erect; scales dark brown, linear-lanceolate, ca. 6 × 1 mm, apex long acuminate, bristlelike, margin sparsely denticulate, clathrate. Fronds clustered; stipe 1-3 cm, appressed, glabrous; lamina leathery, obovate-lanceolate or oblong-lanceolate, 15-40 × 2-10 cm, widest above middle, apex acuminate or caudate, base attenuate along stipe; costa only visible at base; veins abundantly reticulate, raised abaxially, invisible adaxially. Soral lines continuous or interrupted, partly netted; paraphyses filiform, longer than sporangia. Spores trilete, tetrahedral-globose, surface papillate.

Antrophyum callifolium is a very variable species, particularly in the width of the lamina. Antrophyum annamense represents an extreme form with large, broad lamina, which is found in Hainan and N Vietnam, but intermediate forms link them together. It might be conspecific with A. reticulatum (G. Forster) Kaulfuss.

Epiphytic on tree trunks or epilithic on rocks; 100-1600 m. Guangxi, Hainan, Yunnan [Cambodia, India, Indonesia, Laos, Malaysia, Philippines, Sri Lanka, Thailand, Vietnam; Australia].