Family

Polypodiaceae

Nomenclature

Microsorum musifolium (Blume) Copel., Univ. Calif. Publ. Bot. 16: 112. 1929; Bosman, Leiden Bot. Ser. 14: 94. 1991; Petchsri et al., Natural Hist. J. Chulalongkorn Univ. 9(1): 99. 2009. – Polypodium musifolium Blume, Enum. Pl. Javae 2: 134. 1828. – Pleopeltis musifolia (Blume) T.Moore, Index Fil. 78. 1857. – Drynaria musifolia (Blume) J.Sm., Cat. Cult. Ferns 14. 1857. – Type: Blume s.n. (L), Java.

Description

Rhizome moderately long creeping, cylindrical to dorso-ventrally slightly flattened, 5.5–8.4 mm in diameter, not waxy ; roots densely set forming a thick mat; phyllopodia obscure, up to 10 mm apart. Rhizome anatomy: vascular bundles in cylinder 17–21, bundle sheaths collenchymatous, sclerenchyma strands at least 50, scattered, ground tissue without cavities. Rhizome scales densely set at apex, appressed, peltate, widest below or about the middle, 3.2–5.0 by 1.2–1.6 mm, clathrate, marginal region hyaline, margin entire, apex acuminate, central region dark, glabrous, inner layer of thickened cell walls smooth. Fronds simple, well proportioned to the rhizome diameter; stipes absent or indistinct, up to 6 mm in diameter, with a few scales; widest about or above the middle, 35–98 by 5–11.2 cm, light green when living, subcoriaceous, with short glandular hairs and a few scales, acicular hairs absent, base truncate to obtuse, margin entire-undulate, apex acute to acuminate. Venation pattern: veins forming a more or less regular row of nearly equally sized areoles between each pair of adjacent secondary veins, all veins clearly distinct; secondary veins 7–15 mm apart, more or less straight, dichotomously branched near the margin of the lamina; tertiary veins catadromous, 6–10 between adjacent secondary veins, interconnected by some quaternary veins; smaller veins variously anastomosing; free included veins simple, once- and in part twice-forked, pointing to all sides. Sori superficial, round, sometimes in part confluent, 1.2–1.5 mm in diameter, spreading all over the lamina or restricted up to the distal 1/2, absent in the marginal areoles, occasionally present in all areoles, 33–46 per square cm, not on tertiary veins, occasionally in part on quaternary veins, irregularly scattered on the smaller anastomosing veins and on the free included veins. Paraphyses uniseriate, 2- or 3-celled. Sporangia: annulus (18–) 19- or 20-celled, indurated cells (12) 13 or 14, hypo- and epistomial cells together 6 or 7. Spores concavo-convex, hyaline, 43–53 by 30–37 micrometres, colliculate, the elevations not very prominent, rounded , about 5 micrometres wide.

Distribution in Thailand

PENINSULAR: Narathiwat.

Wider Distribution

Southern Myanmar, Peninsular Malaysia, Sumatra, Indonesia, Borneo, Philippines and New Guinea.

Ecology

Low epiphytes or lithophytesin tropical evergreen forests at low altitudes.

Proposed IUCN Conservation Assessment

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