Microsorum heterocarpum (Blume) Ching

Family

Polypodiaceae

Nomenclature

Microsorum heterocarpum (Blume) Ching, Bull. Fan Mem. Inst. Biol. 4: 295. 1933; Holttum, Rev. Fl. Malaya ed. 1, 2: 178, f. 87. 1955 [‘1954’]; Tagawa & K.Iwats, SouthE. Asian Stud. 3(3): 77. 1965; Tagawa & K.Iwats., SouthE. Asian Stud. 5: 52. 1967; Tagawa & K.Iwats., Fl. Thailand 3: 526. 1989; Nooteboom, Blumea 42: 327. 1997; Bosman et al., Fl. Males., Ser. II, Ferns and Fern Allies 3: 109. 1998; Boonkerd & Pollawatn, Pterid. Thailand: 279. 2000. – Polypodium heterocarpum Blume, Fl. Javae Fil.: 167, t. 75. 1829. – Type: Blume s.n. (L.), Java.

Description

Rhizome creeping, 2–6 mm diam., bearing fronds rather closely spaced, scaly on young portion; scales ovate-oblong with gradually narrowing attenuate apex, 1.5–5 by 0.5–2 mm, dark brown, clathrate, the central cells larger and thick-walled, the apical portion with longitudinal cells with toothed margin. Fronds slightly dimorphic or not. Stipes 0.5–30(–45) cm long, winged nearly to the base, not so distinct from the midrib of the basal part of laminae, stramineous, dark and scaly at base. Laminae narrowly oblong, acuminate to attenuate at apex, broadest at middle or lower portion, cuneately narrowing and broadly decurrent downwards to the wings of stipes, subentire or undulate at margin, 20–70 by 3.5–15 cm, not distinctly dimorphic but the soriferous fronds usually taller with long stipes; lateral main veins distinct, the other veins visible, anastomosing to form copious areoles with included veinlets; papyraceous. Sori usually at junction of veinlets, with elongate receptacles, round or elongate, irregularly scattered on the laminae underneath.

Distribution in Thailand

SOUTH-WESTERN: Phetchaburi; PENINSULAR: Trang, Songkhla.

Wider Distribution

Throughout Malesia.

Ecology

On moist rocks by streams or on rather dry slopes in dense evergreen forests at low altitudes.

Similar species

Leptochilus hemionitideus (C.Presl) Noot.

Proposed IUCN Conservation Assessment

Least Concern (LC). This species is widespread and not under any known threat.

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