Diplazium procumbens Holttum (1940: 95)

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 : 48

21. Diplazium procumbens Holttum (1940: 95) . Fig. 27 .

Type : MALAYSIA. Pahang, R. E . Holltum 36503 (holotype K000443463 !) .

Plants terrestrial. Stems creeping, 1.5–2.0 cm diameter, densely covered with scales at apex; scales 8–10 × 0.7–1.0 mm, linear with long tail apex, concolorous, brown, margin toothed. Fronds up to 1.4–1.6 m, bipinnate; petioles 70–80 cm, 5–6 mm diameter, glabrous, deep green, dark at lower portion. Laminae 75–80 × 67–72 cm, deltoid in outline, gradually narrowing upwards, long acuminate apex, glabrous, papyraceous, light green; pinnae 45–50 × 18–20 cm, alternate, oblong in outline stalked; stalks 2.5–3.0 cm, largest at lower pinnae; pinnules 8–9 ×2.0– 2.5 cm, alternate, oblong, apex long acuminate to attenuate, base truncate, lobed at margin; lobes about ¾ way to costule, apex obtuse, margin subentire to dentate, stalked; stalks 1–2 mm; veins pinnate, 4–5 pairs, free, once forked. Sori 2–4 mm, elongate along veinlets, diplazoid, close to midrib, indusiate; indusia linear, very thin, persistance. Spores monolete, 47.5–57.5 × 25.0–32.5 μm, bilateral, concavo-convex to plano-convex, perispore present; ornamentation: prominent wing folds.

Thailand: —SOUTH-WESTERN: Petchaburi (Kaeng Krachan National Park); Prachuap Khiri Khan (Khao Luang).

Distribution: — Sri Lanka, Malaysia.

Ecology: —On moist and shady area, near stream at about 1,300 m elev.

Specimens Examined:— THAILAND. Phetchaburi, Kaeng Krachan, D.J. Middleton et al. 1762 (BKF). MALAYSIA. Pahang, B.E.G. Molesworth-Allen 1439 (BM); Pahang, R.E. Holltum 21645 (K); ibis., R.E. Holltum 21646 (K); ibis., R.E. Holltum 36503 (K). SRI LANKA. Namunukula, W.A. Sledge 1192 (BM, K).

Note: —This species is a new record for the Flora of Thailand.

Figures

FIGURE 27. Diplazium procumbens Holttum.A, pinna. B, pinnule with sori. C, scale showing toothed and not black marginal cells. D.J. Middleton et al. 1762 (BKF).