18. Diplazium petrii Tardieu (1932: 67). Figs. 23, 24. Type: VIETNAM. Tonkin, Pételot 3589 (lectotype P01449476!, designated here!; isolectotypes P01449469!, P01449475!, P01449477!, P01449479!). Plants terrestrial. Stems short creeping, 2.0– 2.5 cm, covered with scales throughout; scales 11–20 × 8–10 mm, linear long tail apex, concolorous, black, margin toothed. Fronds 47–96 cm, unipinnate-bipinnatifid to bipinnate; petioles 32– 43 cm, 5–6 mm diameter, deep green when living, stramineous when dry, dark colour at lower portion, scaly at base. Laminae 42–53 × 44–48 cm, deltoid in outline, terminal pinna not distinct, upper pinnae gradually becoming smaller upwards, glabrous, papyraceous, light green; lateral pinnae 20–22 pairs, alternate, 15–18 × 3.0– 3.5 cm, narrowing upward, falcate, apex acuminate, base cordate to subcordate, margin lobed, stalked; stalks 1.0– 1.7 cm, longest at lower pinna, the posterior pinnules usually decurrent to the next one; veins pinnate, veinlets 3–4 pairs, simple or once forked. Sori 2.0– 3.5 mm, elongate, cresentic. Spores monolete, 30.0–42.5 × 20.0–22.5 μm, bilateral, concavo-convex to plano-convex, perispore present; ornamentation: labryrinth. Thailand: —SOUTH-WESTERN:Prachuap Khiri Khan (Huaiyang waterfalls); SOUTH-EASTERN: Chanthaburi (Khao Soi Dao, Pong Nam Ron); PENINSULAR: Nakhon Si Thammarat (Khao Luang, Khao Nan). Distribution: — China, Taiwan Island, Japan, Vietnam, and Philippines. Ecology: —On rather dry mountain slopes in dense evergreen forests at 1,000–1,400 m elev., rather rare. Specimens Examined:— THAILAND. Nakhon Si Thammarat, Khao Luang, M. Tagawa, K. Iwatsuki & N. T4777 (L); ibis., M. Tagawa, K. Iwatsuki, H. Koyama & A. Chintayungkun T8608 (L); Nakhon Si Thammarat, Khao Luang, M. Tagawa, K. Iwatsuki, H. Koyama & A. Chintayungkun T8387 (BKF); Nakhon Si Thammarat, Khao Luang P. Pongkai 118 (BCU); ibis., P. Pongkai 119 (BCU); ibis., P. Pongkai 68 (BCU); ibis., P. Pongkai 69 (BCU); ibis., P. Pongkai 72 (BCU); ibis., P. Pongkai 118 (BCU); ibis., P. Pongkai 119 (BCU); Chiang Rai, Khunkorn waterfalls, P. Ratchata 136 (BCU); Chiang Rai, Khunkorn waterfalls, P. Ratchata 199 (BCU); Prachuap Khiri Khan, Huaiyang waterfalls, Y. Yuyen 95 (BCU). CHINA. no locality, W.T. Tsang 22480 (BM); Yunnan, Z.Y. Han WR0399 (PE). JAPAN. Kyushu, M. Furuse 3853 (PE); ibis., M. Furuse 39018 (PE); ibis., M. Furuse 41609 (PE); Japan, Taito, M. Tagawa 2745 (BM); no locality, M. Tagawa 3551 (PE); Ryukyu, Y. Saiki 1990 (BM); no locality, Y. Saiki s.n. (PE). TAIWAN ISLAND. Taitung, C.T. Choi 11471 (PE); ibis., C.T. Choi 114889 (PE); ibis., C.T. Choi 11499 (PE); ibis., C.T. Choi 12264 (PE); ibis., C.T. Choi 12834 (PE); Yilan, D.E. Boufford et al. 25188 (PE); no locality, H. Tsung-Hsin & H. ChiHsing 1387 (BM); Yilan, T.T. Chen et al. 11471 (PE); ibis., T.T. Chen et al. 12691 (PE); Teipei, Z.Y. Han 3703-1 (PE); ibis., Z.Y. Han 3703-2 (PE); ibis., Z.Y. Han 3703-3 (PE). Note: — We found five syntypes of D. petrii at P that collected by Pételot from Tonkin, Vietnam. We selected Pételot 3589 (P01449476!) as the lectotype because it is the most complete specimen.