Pleocnemia irregularis (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Pleocnemia irregularis (C. Presl) Holttum

Protologue: Kew Bull. 29: 347 (1974).

Family: Dryopteridaceae

Chromosome number: 2n= 82

Synonyms

Dictyopteris irregularis (C. Presl) C. Presl (1836), D. difformis (Blume) T. Moore (1858), Tectaria irregularis (C. Presl) Copel. (1908), Arcypteris irregularis (C. Presl) Ching (1940).

Vernacular names

• Indonesia: paku andam (Malay), paku kapal, paku kebo (Sundanese)
• Malaysia: paku siar.

Origin and geographic distribution

P. irregularis is distributed from southern Burma (Myanmar) throughout South-East Asia to the Caroline Islands, Solomon Islands and Fiji.

Uses

In South-East Asia the succulent, young and still not unfolded leaves of P. irregularis are eaten raw as a salad or steamed as a vegetable. As a steamed vegetable, mixed with diverse pounded spices and grated coconut, is considered one of the most savoury Indian dishes. A poultice of crushed roots and rhizomes is applied to scabies-infected skin, while a poultice of pounded leaves and shoots for rubbing on the body against (malaria) fever. An infusion of the leaves in hot water is said to be effective against diarrhoea. The woolly scales may be used as a styptic instead of the hairs of Cibotium barometz (L.) J. Smith.

Production and international trade

P. irregularis is not cultivated commercially and no international trade exists. Young leaves are collected from the wild and locally consumed as a vegetable, or offered for sale on local markets. Parts of the scaly rhizomes and petiole bases of P. irregularis are also offered for sale locally, e.g. in Indonesia as "penawar jambe" for the woolly styptic scales.

Properties

The uncooked leaves of P. irregularis are slightly astringent and somewhat musty. It tastes better when mixed with other salad material since it is rather sweet.

Description

A large, terrestrial, bipinnatifid fern, up to 2.5 m tall, with remarkably large basal pinnules. Rhizome short, erect or suberect but not arborescent, its apex and the bases of the petioles densely covered with scales; scales thin, linear or lanceolate, 3-4 cm × 2 mm, margins crispate or irregularly dentate, apex long acuminate, dark brown. Leaves deeply bipinnatifid or pinnate towards base; petiole stout, 30-80 cm long, green when living and pale when dry, dark at the base, glabrescent except for the scales at the base; lamina lanceolate, 50-200 cm × 60-70 cm, firm, herbaceous, rather light green, drying brown-olivaceous, when young conspicuously pale, firmly herbaceous, glabrous; pinnae opposite, numerous, the basal pair the largest; basal pinnae asymmetrically subdeltoid with a basal basiscopic pinnule up to 12-20 cm × 6 cm, free, sessile, deeply lobed, usually much longer than the next ones; suprabasal pinnae lanceolate-oblong, up to 40 cm × 12 cm, petiolate, on large leaves pinnate at the base with few pairs of sessile and usually more or less adnate pinnules, the distal part deeply lobed, apex acute to acuminate; lobes falcate, usually about 1 cm wide, the longest with crenate margins and acute apex, the shorter more distal lobes entire with blunt apex, proximal sinuses rounded at the base, distal sinuses narrowly angled with a broad tooth in the angle; distal pinnae gradually less deeply lobed, the uppermost grading into the petiolate, pinnatifid, deltoid apex of the lamina; rachis and base of costae adaxially with short hairs, costules, veins, distal part of the costae, and surface above glabrous, rachis and costae abaxially glabrescent or bearing rather stiff multicellular hairs up to 1 mm long, costules and veins usually hairless but with small round red glands similar to those in the sori. Veins forming a single narrow row of areoles along either side of costae and shorter areoles on either side of costules, the whole of the rest of the lamina filled with more or less elongated 4-6-sided areoles, sometimes with an included free veinlet. Sori round or often extending along the veins and sometimes confluent, small, close, usually scattered irregularly, exindusiate; sporangia often bearing round red glands either near annulus or on a hair attached to the stalk.

Other botanical information

Within Dryopteridaceae , Pleocnemia C. Presl belongs to the tribe Dryopteridoideae . In the literature Pleocnemia has been variously classified in Aspidiaceae, Athyriaceae, Polypodiaceae and Tectariaceae . In Flora Malesiana Pleocnemia is classified into the so-called Tectaria group, without a further family classification. Pleocnemia comprises about 19 species, distributed in the Asian Old World tropics and subtropics. Species of Pleocnemia without indusia have also been placed in the genera Dictyopteris C. Presl and Arcypteris Underw.

In South-East Asia 2 species closely related to P. irregularis are similarly used as a vegetable:

• P. macrodonta (Fée) Holttum (synonyms Tectaria cumingiana (Hook.) C. Chr., T. irregularis auct.). Distributed in Sarawak, the Philippines, eastern New Guinea, Admirality Islands and New Britain. It differs from P. irregularis by scales up to 2 cm long and wider than 1 mm; pinnae conspicuously pinnate, pinnules sessile and mostly adnate, base unequally cuneate, margins lobed to or more than one third towards the midrib; sori in 2 close rows on either side of each costule, often somewhat confluent, with additional sori near the sinuses in the broader pinnules. In Thailand and Vietnam very large plants of P. irregularis occur which have more fully bipinnate leaves than those in Malesia; these plants have been erroneously identified as P. macrodonta but they are much less fully bipinnate and their sori are arranged differently.

• P. brongniartii (Bory) Holttum (synonym: Dictyopteris pteroides C. Presl). Distributed in New Guinea and the Philippines. It differs from P. irregularis by size and branching of the leaves, and the shape of the pinnules is similar to P. macrodonta ; the sori, however, are all near the margins of the lobes of pinnules or of pinnae near the leaf apex.

Ecology

P. irregularis is common in partial shade in lowland forest and on the edge of forested hills, especially on slopes. It is found in the inner corners of winding roads, around villages and in plantations. It grows on heavy clays, calcareous clays or stony humus-rich soils, from sea-level up to about 800 m altitude, sometimes in clusters. It tolerates drier conditions than many other terrestrial forest ferns. In Thailand it is recorded on rather dry slopes in dense forest.

Propagation and planting

P. irregularis is easily propagated by spores. Vegetative propagation is possible by rhizome parts.

Husbandry

P. irregularis is not cultivated commercially. When planted, it needs light shade and it seems to be tolerant of regular pruning.

Harvesting

Croziers and other young leaves of P. irregularis are collected from the wild for own consumption. When sold on the local market they are often bundled with a bamboo strip.

Genetic resources

P. irregularis does not seem in danger of genetic erosion due to its wide distribution and common occurrence. Germplasm collections are not known to exist.

Breeding

A natural hybrid of P. irregularis and an unknown, large bipinnate species (possibly P. olivacea (Copel.) Holttum from western Malesia) has been found in Sarawak and named Pleocnemia × intermedia Holttum.

Prospects

In South-East Asia P. irregularis will continue to be used as a vegetable and as a medicine. Further research on its chemical properties, followed by research toward possibilities for domestication and marketing are worth consideration.

Literature

• Holttum, R.E., 1951. The fern-genus Arcypteris Underwood (Dictyopteris Presl sensu Fée). Reinwardtia 1(2): 191-196.
• Holttum, R.E., 1966. A revised flora of Malaya. 2nd Edition. Vol. 2. Ferns of Malaya. Government Printing Office, Singapore. pp. 537-539.
• Holttum, R.E., 1974. The fern-genus Pleocnemia. Kew Bulletin 29: 341-357.
• Holttum, R.E., 1991. Tectaria group. In: Kalkman, C. & Nooteboom, H.P. (Editors): Flora Malesiana. Series 2. Pteridophyta: Ferns and fern allies. Vol. 2, part 1. Rijksherbarium/Hortus Botanicus (under the auspices of Foundation Flora Malesiana), Leiden, The Netherlands. pp. 12-15.
• Kramer, K.U., 1990. Dryopteridaceae. In: Kramer, K.U. & Green, P.S. (Volume editors): Pteridophytes and gymnosperms. In: Kubitzki, K. (Series editor): The families and genera of vascular plants. Vol. 1. Springer-Verlag, Berlin, Germany. pp. 101-144.
• Ochse, J.J. & Bakhuizen van den Brink, R.C., 1980. Vegetables of the Dutch East Indies. 3rd English edition (translation of "Indische groenten", 1931). Asher & Co., Amsterdam, The Netherlands. pp. 596-598.
• Sastrapradja, S. & Afriastini, J.J., 1985. Kerabat paku [Ferns]. LBN 33/Seri Sumber Daya Alam 123. Lembaga Biologi Nasional-LIPI, Bogor, Indonesia. pp. 50-51.
• Zamora, P.M. & Co, L., 1986. Guide to Philippine flora and fauna. Vol. 2. Economic ferns, endemic ferns, gymnosperms. Natural Resources Management

Center, Ministry of Natural Resources and University of the Philippines, Goodwill Bookstore, Manila, The Philippines. pp. 53-54.

Authors

Dedy Darnaedi & Titien Ngatinem Praptosuwiryo