Diplazium petrii Tardieu (1932: 67)

Pongkai, Puttamon, Zhang, Li-Bing, Boonkerd, Thaweesakdi & Pollawatn, Rossarin, 2023, Revision of the fern genus Diplazium (Polypodiales: Athyriaceae) in Thailand, Phytotaxa 631 (1), pp. 1-69 : 42

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 .

Figures

FIGURE 23. Diplazium petrii Tardieu. A, whole plant. B, a part of pinna with sori. C, scale showing toothed and not black marginal cells. P. Pongkai 68 (BCU).

FIGURE 24. Diplazium petrii Tardieu. Lectotype of D. petrii Tardieu (Pételot 3589, P01449476).