Laportea decumana (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Laportea decumana (Roxb.) Wedd.

Protologue: Arch. Mus. Hist. Nat. Paris 9: 127 (1856).

Family: Urticaceae

Synonyms

• Urtica decumana Roxb. (1832).

Vernacular names

• Indonesia: daun gatal besar (Moluccas), afa (Ayawasi, Papua)
• Papua New Guinea: irongo (Oro Province), ton (Central Province), lang (Wutun, West Sepik).

Distribution

From southern Borneo eastward to Sulawesi, the Moluccas and New Guinea. Locally cultivated in New Guinea and the Moluccas.

Uses

In many areas of Papua New Guinea the leaves are rubbed on various parts of the body to counteract fever, body pains, fatigue, stomach-ache and headaches. For the same indications the leaves are merely stroked or gently beaten on the skin in the Moluccas. Locally in the highlands of Papua New Guinea, fresh young leaves are eaten with sweet potato or taro for intestinal pains.

Observations

• A monoecious, perennial herb, subshrub or shrub up to 2 m tall, stem woody, well-branched, densely armed with irritant hairs.
• Leaves broadly ovate, rarely elliptical, 20-30(-35) cm × (6-)12-18 cm, base rounded to cordate, apex long acuminate, margin serrulate to denticulate, strongly rugose, densely woolly especially at the lower surface, with long irritant hairs on both surfaces, petiole (2-)5-8(-10) cm long, long rigid irritant hairs present, stipules up to 2 cm long, with short irritant hairs.
• Panicle unisexual, well-branched, usually solitary, the male up to (10-)16-20(-25) cm × (4-)6-10(-15) cm, the female up to (20-)30-40(-55) cm × (4-)8-15(-20) cm, bracteolate.
• Male flowers pedicellate, about 2 mm long, glabrous except for a few rather long irritant hairs, filaments reflexed, interfloral bracts present.
• Female flowers pedicellate, glabrous except for a few rather long irritant hairs, stigma linear, unbranched, up to 3 mm long, interfloral bracts present; achene pyriform, stipitate, to 2.5 mm × 2.5 mm, smooth, perianth persistent, stigma persistent, pedicel slightly to strongly winged laterally.
• Achene dispersed free from the perianth.

L. decumana is common in forest margins and as undergrowth in hedges at low elevations.

Selected sources

• [74] Backer, C.A. & Bakhuizen van den Brink Jr, R.C., 1964—1968. Flora of Java. 3 volumes. Noordhoff, Groningen, the Netherlands. Vol. 1 (1964) 647 pp., Vol. 2 (1965) 641 pp., Vol. 3 (1968) 761 pp.
• [83] Balun, L. & Holdsworth, D.K., 1988. Ethnomedicine of the Gulf Province of Papua New Guinea. Part 1: The mountains around Kanabea and Kaintiba. International Journal of Crude Drug Research 26(1): 51—55.
• [407] Heyne, K., 1950. De nuttige planten van Indonesië [The useful plants of Indonesia]. 3rd Edition. 2 volumes. W. van Hoeve, 's-Gravenhage, the Netherlands/Bandung, Indonesia. 1660 + CCXLI pp.
• [416] Holdsworth, D., 1984. Phytomedicine of the Madang Province, Papua New Guinea Part I. Karkar Island. International Journal of Crude Drug Research 22: 111—119.
• [418] Holdsworth, D.K., 1977. Medicinal plants of Papua New Guinea. Technical Paper No 175. South Pacific Commission, Noumea, New Caledonia. 123 pp.
• [419] Holdsworth, D.K., 1987. Medicinal plants of the Central Province of Papua New Guinea. Part. IV. The Goilala Mountain People. International Journal of Crude Drug Research 25: 231—235.
• [420] Holdsworth, D.K., 1987. Medicinal plants of the Morobe Province, Papua New Guinea. Part V. The Upper Watut. International Journal of Pharmacognosy 25: 225—230.
• [422] Holdsworth, D.K., 1989. High altitude medicinal plants of Papua New Guinea. International Journal of Crude Drug Research 27(2): 95—100.
• [427] Holdsworth, D.K., 1993. Medicinal plants of the Oro (Northern) Province of Papua New Guinea. International Journal of Pharmacognosy 31: 23—28.
• [428] Holdsworth, D.K. & Balun, L., 1992. Medicinal plants of the East and West Sepik Provinces, Papua New Guinea. International Journal of Pharmacognosy 30: 218—222.
• [432] Holdsworth, D.K. & Lacanienta, E., 1981. Traditional medicinal plants of the Central Province of Papua New Guinea. Part II. Quarterly Journal of Crude Drug Research 19(4): 155—167.
• [433] Holdsworth, D.K. & Mahana, P., 1983. Traditional medicinal plants of the Huon Peninsula, Morobe Province, Papua New Guinea. International Journal of Crude Drug Research 21: 121—133.
• [434] Holdsworth, D.K. & Rali, T., 1989. A survey of medicinal plants of the Southern Highlands, Papua New Guinea. International Journal of Crude Drug Research 27: 1—8.
• [435] Holdsworth, D.K. & Sakulas, H., 1986. Medicinal plants of the Morobe Province. Part II. The Aseki Valley. International Journal of Crude Drug Research 24: 31—40.
• [436] Holdsworth, D.K. & Sakulas, H., 1987. Medicinal plants of the Morobe Province, Papua New Guinea. Part IV. The Snake River Valley. International Journal of Crude Drug Research 25(4): 204—208.
• [437] Holdsworth, D.K. & Sakulas, H., 1987. Medicinal plants of the Western Highlands, Papua New Guinea. International Journal of Crude Drug Research 25: 171—176.
• [438] Holdsworth, D.K. & Sakulas, H., 1992. High altitude medicinal plants of Papua New Guinea. Part II. Mount Wilhelm, Simbu Province. International Journal of Pharmacognosy 30(1): 1—4.

Main genus page

• Laportea

Authors

• J.L.C.H. van Valkenburg