Aporosa frutescens (PROSEA)
Introduction |
Aporosa frutescens Blume
- Protologue: Bijdr.: 514 (1825).
- Family: Euphorbiaceae
- Chromosome number: 2n= unknown
Synonyms
- Aporosa fruticosa (Blume) Muell. Arg. (1866),
- Aporosa similis Merr. (1914),
- Aporosa banahaensis (Elmer) Merr. (1923).
Aporusa Blume is considered as an orthographic variant of Aporosa Blume.
Vernacular names
- Bastard rukam (En)
- Indonesia: berih (Javanese), kayu malam (Bangka), sasah (Sundanese)
- Malaysia: mesekam, rukam utan (Peninsular)
- Philippines: hauai (Manobo). Burma (Myanmar): liyo
- Thailand: khruen (Trat).
Origin and geographic distribution
A. frutescens is distributed from lower Burma and south-eastern Thailand through Malaysia, to the Philippines and Indonesia (Sumatra, Java, Kalimantan, Sulawesi and the Moluccas).
Uses
The bark, called "sasah" was formerly used in the batik industry in Java as a mordant, for fixing the red dye of Morinda citrifolia L., similarly to the bark of Symplocos Jacq. Sometimes the leaves were used for that purpose. The bark was also occasionally used to prepare a black dye.
The wood is considered second-class and is sometimes used for building houses and making tools.
Properties
The bark is probably rich in aluminium, which explains the action as a mordant. No chemical analysis of A. frutescens is available, but accumulation of aluminium is reported as common in the genus Aporosa. Crushed leaves smell of alum, and the yellowish colour of dried leaves also indicates a high content of aluminium. The wood is hard, yellow-brown, and radially striate.
Description
- A small, conical, dioecious tree up to 16 m tall and 35 cm in diameter, but usually much smaller; bark thin, finely flaky, pale brownish.
- Leaves alternate, simple, papery to thin-leathery, oblong to lanceolate, 6-20 cm √ó 2-6(-9) cm, acuminate, bearing 8-13 small glands along the margins; petiole 6-12 mm long.
- Flowers unisexual, minute; male flowers in densely flowered axillary, almost sessile, up to 2.5 cm long spikes, each flower with 2(-3) stamens; female flowers in fascicles, each flower with an ovoid-globose ovary.
- Fruit a subglobose capsule, 1-1.5 cm in diameter, shortly stalked, green to red, usually 3-seeded.
- Seeds flattened, surrounded by orange-red pulp.
Ecology
A. frutescens grows in rain forest and occurs up to 1700 m altitude. It often grows in more open places in the forest and on wet ground, and is locally common.
Prospects
The supposed high aluminium content makes this plant a suitable mordant in combination with mordant dyes, and a good alternative to chemicals such as metallic salts which cause more injurious waste products of the dye bath.
Literature
- Backer, C.A. & Bakhuizen van den Brink, R.C., 1963. Flora of Java. Vol. 1. Noordhoff, Groningen, the Netherlands. p. 457.
- Corner, E.J.H., 1988. Wayside trees of Malaya. 3rd ed. Vol. 1. The Malayan Nature Society. United Selangor Press, Kuala Lumpur. pp. 270-273.
- Ridley, H.N., 1924. The flora of the Malay Peninsula. Vol. 3. Reeve & Co., London. p. 241.
- Whitmore, T.C., 1973. Tree flora of Malaya, a manual for foresters. Vol. 2. Longman, London. pp. 58-61.
Authors
C.C.H. Jongkind