Description from Flora of China
Plants 24-40 cm tall. Rhizome erect, short, apex scaly; scales dark brown, narrowly triangular, entire. Fronds caespitose; stipe gray to dark brown, 4-10(-15) cm, adaxially sulcate, with brown narrowly triangular or stellate scales, often becoming subglabrous; lamina narrowly triangular to ovate, 13-26 × 3-8 cm, apex acuminate-caudate, bipinnate; pinnae 10-16 pairs, subopposite to alternate, stalk up to ca. 2 mm, basal pinnae largest or slightly reduced, middle pinnae ovate, 2.5-4(-7) × 1.2-1.6 cm, apex obtuse to subacute, 1-pinnate; pinnules 2-4(-7) pairs, anadromous, first acroscopic pinnule largest, narrowly obovate-obtrullate, 8-10 × 4-6 mm, distal pinnules narrowly cuneiform, basiscopic pinnules cuneiform-falcate, base narrowly cuneate, almost sessile, lateral side entire, apex serrate and obtuse. Costa sulcate with raised supravascular ridge adaxially, green. Veins distinct, raised adaxially, anadromously branching, not reaching margin. Fronds firmly herbaceous, brownish green when dry; rachis gray to dark brown abaxially, becoming green toward apex, subglabrous, adaxially sulcate. Sori 2-5 per pinnule, linear, 2-6 mm; indusia pale brown, linear, membranous, entire, opening toward costule, persistent.
Asplenium hainanense is similar to A. gracilifolium Copeland and to small forms of A. affine but never proliferous.
On wet rocks at streamsides in forests; 400-700 m. Hainan [Thailand, Vietnam].