热带铁角蕨 re dai tie jiao jue

Plants up to ca. 80 cm tall. Rhizome long creeping, scaly; scales dark brown, narrowly triangular, entire. Fronds separate along rhizome; stipe dull, dark grayish brown, 20-40 cm, subglabrous, semiterete, grooved adaxially; lamina oblong to elliptic, 30-45 × 12-20 cm, pinnate; pinnae 12-25(-30) pairs, opposite or subopposite, distinctly stalked, lower pinnae not or only slightly reduced, median pinnae 7-13 × 0.8-1.5 cm, narrowly rhomboid-lanceolate, falcate, base asymmetrical, acroscopic side cuneate-truncate, basiscopic side narrowly cuneate, margin biserrate often with long teeth, apex long acuminate to caudate, terminal pinna reduced, apex pinnatifid. Costa abaxially slightly raised, adaxially with a shallow longitudinal furrow. Veins prominent, several times forked, distally in pinnae almost running parallel. Fronds (sub)leathery, dark brown when dry, pinna stalk with small dark brown scales and becoming subglabrous when old; rachis dark gray-brown, semiterete, adaxially grooved. Sori linear, 8-12 mm, on acroscopic veins; indusia brown, linear, entire, opening toward costa. Perispore reticulate, without ridges.

On rocks in forests; ca. 1300 m. Hainan [Laos, Philippines, Vietnam].

Asplenium lepturus is similar to A. polyodon but has more narrow and caudate pinnae, a widely creeping rhizome, and a peculiar perispore pattern. It shares these characters with a number of tropical taxa, e.g., A. contiguum Kaulfuss from Hawaii, the neotropical A. serra Langsdorff & Fisher, the African A. friesiorum C. Christensen group, and A. nitens Swartz from Réunion.