Description from Flora of China
Plants 5-7 cm tall. Rhizomes erect, short, scales black lanceolate. Fronds clustered; stipe castaneous-black, slightly glossy, 2-3 cm, as slender as a hair, glabrous; lamina oblong in outline, 3-5 × 1-1.5 cm, 1-pinnate; costae and stalks same color as stipe; pinnules 3 or 4 pairs, 6-9 mm apart, opposite, obliquely spreading; stalk 1.5-4 mm, 1/3-1/2 as long as pinnules, articulate at end, persistent after pinnules fall; pinnules narrowly ovate or narrowly flabellate, 4-6 × 2.5-4 mm, papery, brownish green, both surfaces glabrous, base cuneate, both sides entire and undulate, upper margins subtruncate, with one sinus at middle; terminal pinnae same shape as and slightly larger than lateral pinnae; veins undivided, 4 forked veinlets arising from base, visible on both surfaces. Sori 1 per pinnule; false indusia brown, reniform or elliptic, leathery, upper margins depressed, persistent.
Ching initially misidentified this species as Adiantum gravesii Hance. Adiantum lianxianense is believed to be extinct due to habitat loss (China Plant Specialist Group 2004. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4. ; accessed 27 Apr 2011).
● Gregarious on wet calcareous rocks and calcitic soils. Guangdong (Lianxian).