Microlepia speluncae (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Microlepia speluncae (L.) T. Moore

Protologue: Index fil.: 93 (1857).

Family: Dennstaedtiaceae

Chromosome number: 2n= 86, 172, 258

Synonyms

Microlepia flaccida (R. Br.) J. Sm. (1842), Davallia speluncae (L.) Baker (1867).

Vernacular names

• Cave fern, limpleaf fern (En)
• Thailand: kut phi (central), chon (south-western), neraphusi (peninsular).

Origin and geographic distribution

M. speluncae is pantropical and occurs in Africa, Australia and tropical America. In the latter area it may have been introduced.

Uses

In Sepik River (Papua New Guinea), M. speluncae was used as a green vegetable. In the Nicobar Islands the crushed leaves are applied on the skin as febrifuge.

Production and international trade

M. speluncae is only used and traded locally.

Properties

Several 1-indanone-type sesquiterpenes (pterosins and pterosides) have been isolated from the leaves, e.g. 13-hydroxy-3(R)-pterosin D or spelosin, 13-hydroxy-3(R)-pterosin D 3-O-α-L-arabinopyranoside, 3(R)-pterosin D 3-O-α-L-arabinopyranoside and 2(R),3(R)-pterosin L 3-O-α-L-arabinopyranoside and the 2-O-acetyl derivative of 4-O-p-coumaroyl-D-glucose.

Description

A finely cut terrestrial fern. Rhizome short-creeping, the young parts covered with short pale hairs. Leaves in two rows, approximate, monomorphic, deeply 3(-5)-pinnatifid to tripinnate; petiole (20-)45-60(-100) cm long, 2-8 mm in diameter, green to purplish, minutely pubescent, glabrous near the base; lamina triangular to ovate-lanceolate, 35-175 cm × 20-120 cm, the basal pinnae usually somewhat reduced, herbaceous to membranaceous, more or less pubescent to setose, or with few to many long, flaccid, glistening, scale-like hairs; rachis indumentum like the leaf surface; pinnae ovate-lanceolate, 16-70 cm × 15-18 cm, petiolate, the basal acroscopic pinnule often the largest; pinnules narrowly deltoid, acuminate, pinnate near the base and lobed almost to the costa, the basal acroscopic segment the largest; ultimate segments 3-4 mm wide, oblique, unequilateral at the base, margins crenate to lobed, apex obtuse; veins conspicuous but hardly raised, concolorous. Sori near the base of the sinuses between the lobes, 2-10 to a segment, varying in size, with a conspicuous hydathode on the opposing surface; indusium half-cup shaped, with few to many hairs, rarely glabrous; sporangia many, often hiding the indusium. Spores trilete, pale, finely echinate or smooth.

Other botanical information

Microlepia Presl is predominantly found in tropical to warm temperate Asia where about 45 species occur. It is notorious for its species being hard to discriminate due to morphological variation (hairiness, degree of leaf cutting), age and habitat. Many of these forms have been described as species, varieties and forms, but their status still remains unclear. M. scaberula (L.) Mett. ex Kuhn of New Guinea and Polynesia is used in the Rotuma Islands where the immature leaves are applied against pain in the thorax.

Ecology

M. speluncae occurs in rain forest, forest and thicket margins, where there is shelter for the roots and sufficient bright light reaches the leaves, often on moist banks, river banks or alluvial flats, up to 1200 m altitude. It is also found on the trunks of oil palms where some humus has accumulated.

Propagation and planting

M. speluncae can be propagated by spores but is most easily propagated by rhizome cuttings.

Genetic resources and breeding

M. speluncae is widespread and does not seem to be endangered by genetic erosion. No germplasm collections or breeding programmes are known to exist.

Prospects

The pharmacological properties of M. speluncae and other members of the genus might receive some attention, but on the whole it will probably remain a fern of minor importance.

Literature

• Croft, J.R., 1982. Ferns and man in New Guinea. Paper presented to Papua New Guinea Botany Society, 1982.
• Dagar, H.S., 1989. Some pteridophytes in the ethnology and life of the Nicobarese. Journal of Economic and Taxonomic Botany 13(2): 395-397.
• Holttum, R.E., 1966. A revised flora of Malaya. 2nd Edition. Vol. 2. Ferns of Malaya. Government Printing Office, Singapore. pp. 307-316.
• Kuraishi, T., Kimura, T., Murakami, T., Saiki, Y. & Chen, C.M., 1984. Chemische und Chemotaxonomische Untersuchungen der Pterophyten 48. Über die Zuckerester aus Plagiogyria euphlebia (Kunze) Mett. und Microlepia speluncae L. [Chemical and chemotaxonomical studies of ferns 48. About the sugar esters from Plagiogyria euphlebia (Kunze) Mett. and Microlepia speluncae L.]. Chemical and Pharmaceutical Bulletin 32: 1998-2000.
• Kuraishi, T., Murakami, T., Taniguchi, T., Kobuki, Y. & Maehashi, H., 1985. Chemical and chemotaxonomical studies of ferns 54. Pterosin derivatives of the genus Microlepia (Pteroidaceae). Chemical and Pharmaceutical Bulletin 33(6): 2305-2312.
• McClatchy, W., 1996. The ethnopharmacopeia of Rotuma. Journal of Ethnopharmacology 50: 147-156.

Authors

Norma O. Aguilar & W.P. de Winter