Diplazium megaphyllum (Baker) Christ (1898: 961)

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 : 29-32

12. Diplazium megaphyllum (Baker) Christ (1898: 961) . Fig. 15 .

Asplenium megaphyllum Baker (1890: 264) .

Type: VIETNAM. Tonkin, Balansa 1836 (lectotype P00642890 !; isolectotypes P00642891 !, K001089145 !, K001089146 !, BM001045380 !; designated by Pacheco & Moran [2003: 91]) .

Plants terrestrial. Stems erect, 3–4 cm diameter, covered with scales at apex; scales 10–12 × 1.0– 1.5 mm, lanceolate with long tail apex, dark brown, margin thick and toothed. Fronds up to 1.30 m, imparipinnate; petioles 50–60 cm, 5–8 cm diameter, deep green, scaly and dark at base. Laminae 60–70 × 40–50 cm, oblong in outline, apex acuminate, terminal pinna distinct, glabrous, papyraceous, deep green; terminal pinna, narrowly-deltoid, apex acuminate, base subtruncate, margin lobed; lateral pinnae 10–12 pairs, alternate, suddenly becoming smaller upward, 15–20 × 4.0– 4.5 cm, oblong, apex acuminate, base subtruncate, margin subentire to crenate, sessile or shortly stalked; stalks 3–4 mm, longest at lower pinnae; veins pinnate, free, veinlets 5–6 pairs. Sori 4–5 mm, elongate along veinlets, on all veinlets, diplazoid, indusiate; indusia linear, thin, persistance. Spores monolete, 52.5–60.0 × 20.0–22.5 μm, bilateral, concavo-convex to plano-convex, perispore present; ornamentation: prominent wing folds.

Thailand: —NORTHERN: Chiang Mai (Doi Chiang Dao), Tak (Doi Musoe), Nakorn Sawan (Doi Musae); EASTERN: Chiyaphum .

Distribution: — China, Taiwan Island, Myanmar and Vietnam.

Ecology: —Along streamlet banks in moist evergreen forests at about 800 m elev.

Specimens Examined:— THAILAND. Chiyaphum, C.F. van Beusekom et al. 4407 (B); Nakhon Sawan, Doi Musae, E. Hennipman 3064 (B, BM, K. L); ibis., E. Hennipman 3065 (BKF). CHINA. Guizhou, X.C. Zhang, Z.Y. Guo & X. Q. Ping 7167 (PE). TAIWAN ISLAND. Nantou, C.T. Choi 11785 (PE); ibis., C.T. Choi 12798 (PE); Nantou, B.F. Lu 17764-2 (PE); Kwarenko, M. Tagawa 3537 (BM). VIETNAM. Tonkin, B. Balansa 1836 (K); Ninh Binh, H. van der Werff et al. 14220 (PE).

Figures

FIGURE 15. Diplazium megaphyllum (Baker) Christ. A, lamina. B, a part of pinna with sori. C, scale showing toothed and black marginal cells. E. Hennipman 3064 (BKF).