Family

Polypodiaceae

Nomenclature

Calymmodon asiaticus Copel., Philipp. J. Sci. 38: 154. 1929; Tardieu & C.Chr., Fl. Indo-Chine 7(2): 526. 1941; Tagawa & K.Iwats., SouthE. Asian Stud. 5:62. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 596, f. 59.6–7. 1989; Boonkerd & Pollawatn, Pterid. Thailand: 241, 289. 2000; Parris, Fl. Pen. Malaysia, Ser. I, Ferns & Lycoph. 1: 138. 2010. – Type: J. & M.S. Clemens 3800, Vietnam, Mt Bana (BM, K, MICH, MO, P, UC).

Description

Lithophytic. Rhizome short, suberect, bearing several fronds in a tuft at apex, sparsely scaly; scales thin, brown, not clathrate, oblong-lanceolate, 1–2 by 0.7 mm. Stipes indistinct, very short, green or brownish, winged to the very base, hairy with pale setose hairs up to 0.3 mm in length. Laminae narrowly lanceolate, gradually narrowing towards both ends, 1.2–3.5(–4.6) cm long by 0.3–0.6 cm wide, deeply lobed to midrib with a wing less than 0.2 mm broad on each side; sterile lobes oblong, ascending, round to moderately acute at apex, entire, up to 2.5 by 0.7 mm; thinly leathery, veins simple, hardly visible, glabrous or nearly so except for hairy midrib; fertile lobes at upper parts of fronds, 2–7 pairs. Sori solitary, the basiscopic half of fertile lobes folded to protect young sori, thus the fertile lobes appearing bivalvate .

Distribution in Thailand

PENINSULAR: Nakhon Si Thammarat, Trang.

Wider Distribution

Thailand, Vietnam, Peninsular Malaysia.

Ecology

On muddy rocks in stream-beds in gloomy dense forests at medium altitudes (600–900 m), rather rare.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species has a large extent of occurrence and is not under known threats in most of its range.  It has been listed as Endangered in Peninsular Malaysia.