Diplazium bellum (C.B. Clarke) Bir (1964:148)

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 : 11-14

2. Diplazium bellum (C.B. Clarke) Bir (1964:148) . Figs. 4 , 5 .

Asplenium bellum C.B. Clarke (1880: 496) .

Type: INDIA. Darjeeling District, Kalimpoon, 5000’, Bohtan [British Bhutan = Kalimpoong, Gorkhaland (W. Bengal)], C.B. Clarke 9484B (lectotype, K001089431 ! designated by Fraser-Jenkins 2008: 269; isolectotype K001089433 !) .

Plants terrestrial. Stem massive, erect, up to 10 cm diameter, apex densely scaly; scale 10–14 × 0.1–0.2 cm, linear, concolorous, brown, margin entire. Fronds bipinnate, 1.3–1.7 m long; petioles 40–50 cm, 0.8–1.0 cm diameter, dark brown, scaly. Laminae 1.0–1.2 × 0.5–0.6 m, outline ovate, apex acuminate to cuspidate, base truncate, glabrous, papyraceous, dark green; rachis groove above, braring out growth at junction of stipe and rachis; pinnae 18–20 pairs, opposite, sessile, lower pairs largest, 35–40 × 13–15 cm, oblong, apex long acuminate, base truncate; pinnule 15–17 pairs, subopposite near base of pinnae but alternate near apex, sessile, the 3 rd to the 4 th pairs from base largest, 8–10 × 1–2. cm, oblong, apex long acuminate, base truncate, margin deeply lobed; lobe very deep about 4/5 way to midrib, 1.0 × 0.5 cm, oblong, apex round, margin slightly dentate; veins free, simple or onec forked, vein group pinnate, veinlet 5–6 pairs, reach to margin; Sori 1.5–2.0 × 1.0 mm, elliptic, on veinlet close to costule, indusiate. Sori totally warped by indusium; indusial membranous, irregulary dehiscing when mature; spores monolete, bilaterally symmetrical, kidney-shaped, 36.0–41.5 × 28–33 µm; perispore present; ornamentation: irregular.

Thailand: —NORTHERN: Chiang mai (Doi Pha Hom Pok, Doi Inthanon).

Distribution: — Bhutan, India, Nepal, China and Myanma.

Ecology: —On shady slopes near streamlets in evergreen forests at 1,700–2,000 m.elev.

Conservation Status: —A small population was found at one locality in Thailand. However, it is distributed in many countries of Asia. Thus, we consider that D. bellum should be registering as “Least Concern (LC)” according to IUCN Conservation Status (IUCN., 2012).

Specimens Examined: —THAILAND. Chiang Rai, Khunkorn waterfalls, P. Ratchata 346 (BCU); Chiang Mai, Doi Pha Hom Pok, P. Pongkai 138 (BCU); Chiang Mai, Doi Inthanon, E. Hennipman 3434, 3435, 3436 (L); No locality, Hansen, B. et al. 10930 (K). INDIA. Sikkim, Clarke, C.B. 9484, 26399 (K); C.R. Fraser-Jenkins 3279, 3298 (L).

Note: —This species is very similar to D. ovatum but differs in having ascending or erect rhizomes. The rhizome size is more than 5 cm in diameter, veins simple or forked, and spores without ridge-shaped ornamentation.

Figures

FIGURE 4. Diplazium bellum (Blume) T. Moore.A, frond. B, pinna.C, pinnule with sori. D, outgrowth (wing) at junction between rachis and costa. E, rhizome and F, scale showing entire and not black marginal cells. P. Pongkai138 (BCU).

FIGURE 5. Diplazium bellum (Blume) T. Moore.