2. Themelium tenuisectum (Blume) Parris, Kew Bull. 52: 740. 1997.
细叶蒿蕨 xi ye hao jue
Polypodium tenuisectum Blume, Enum. Pl. Javae 2: 134. 1828; Ctenopteris tenuisecta (Blume) J. Smith; Grammitis tenuisecta (Blume) Ching.
Stipe 2-3 cm, sometimes subarticulate, with frequent to dense solitary simple dark reddish brown hairs up to 2 mm. Lamina deeply bipinnatifid, linear-oblong to linear-lanceolate, 5-25 × 2-4 cm, apex acuminate, basal normal pinnae slightly shorter, and abruptly shortened to some obliquely orbicular or deltoid pinnae; middle pinnae largest or nearly so, linear to narrowly oblong, 0.8-2 × 0.3-0.5 cm; pinnules linear-triangular, 2-4 × 0.5-1.2 mm, with 1 vein per pinnule, usually with 1 or 2 hairs on apical margin; rachis dark brown, terete at least at base, usually with a very narrow wing connecting adjacent pinnae; veins in pinnules simple, visible or indistinct, extending beyond sorus or not; hairs similar to those on stipe, mainly on rachis (scattered to frequent on abaxial side, scattered on adaxial side), 1 or 2 or none on apical margin of pinnule, sometimes occasional to sparse on abaxial side of costae, absent from both surfaces of lamina and margin (except at apex). Sori orbicular, superficial, 1 at base of pinnule.
Epiphytic on tree trunks in mossy mountain forests; 1400-1700 m. Taiwan (Pingdong, Taidong) [Borneo, Indonesia, Malaysia, New Guinea, Philippines, Thailand; Pacific islands].