Arenga (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Arenga Labill.

Protologue: DC., Bull. Sci. Soc. Philom. Paris 2: 162 (1800).

Family: Palmae

Chromosome number: x= 16;A. porphyrocarpa:n= 16

Arenga comprises about 20 species and occurs from India to southern China, Taiwan and the Ryukyu Islands, and throughout the Malesian region to northern Australia.

Root decoctions and the palm heart (the white, tender tissues of the youngest, unopened leaves at the stem apex) of A. hastata and A. porphyrocarpa are used in traditional medicine in Indonesia and Malaysia, to treat fever, loss of appetite and as a diuretic.

The best-known Arenga species is A. pinnata (Wurmb) Merr. (sugar palm), all parts of which are used, and for a multitude of products. It is also used for medicinal purposes: roots are considered stomachic and pectoral, petioles haemostatic, cicatrizant and diuretic, and fresh, unfermented sap is purgative. Pulped fruits are used as a fish poison. The main product, however, is the palm sugar obtained from the juice tapped from inflorescence stalks and widely used in all kinds of dishes, sweets, drinks and preserves. It can be fermented to make vinegar or palm wine. Other food products are starch, extracted from the pith of the trunk, palm heart and endosperm of immature seeds boiled with sugar. Fibres, obtained from the trunk, roots and leaf stalks and sheaths, are used for matting, sieves, roofs, brushes and brooms, and for tinder. The leaves serve to construct temporary shelters, and the wood of the trunk is used for flooring, furniture, tool handles and as fuelwood. Several other taller Arenga species are used for similar purposes as A. pinnata .

The flesh of Arenga fruits is filled with abundant, irritant needlelike oxalate crystals.

Shrubby or tree palms, small to large, solitary or clustered, usually unarmed; stem often with persistent fibrous leaf bases and sheaths. Leaves arranged spirally, imparipinnate, with usually well developed petiole; sheath eventually disintegrating into a mass of blackish fibres. Inflorescence axillary, often bursting through the leaf sheath, bisexual or unisexual, usually branched to 1-2 orders; peduncle with distinct bracts. Flowers unisexual, 3-merous; sepals rounded, imbricate, leathery; petals connate at base, valvate, leathery; male flowers usually with numerous stamens having short filaments and elongate anthers; female flowers with a globose, 3-celled ovary bearing 2-3 stigmas and few or lacking staminodes. Fruit a globose to ellipsoid berry, often somewhat angled, 1-3-seeded. Seeds planoconvex, smooth, black, with endosperm and lateral embryo.

Arenga is classified in the tribe Caryoteae , together with Caryota and Wallichia , all from tropical Asia. It shows an astonishing range of forms and flowering behaviour.

Most Arenga species are found in primary forest up to 1700 m altitude. A. hastata and A. porphyrocarpa are both forest undergrowth palmlets of lowland forest.

A. hastata and A. porphyrocarpa both seem to have limited areas of distribution. Especially A. hastata may easily become endangered as it is uncommon in lowland forest of Peninsular Malaysia. A. porphyrocarpa is locally common in disturbed forest and seems less liable to genetic erosion. Germplasm collection of Arenga is urgently needed as many species have become very rare.

There is no information on the pharmacological properties of Arenga , and research is needed to evaluate its applications in traditional medicine. Arenga species, including the 2 treated here, have potential ornamental value.

121, 245, 334, 941.

• '

• '

Sri Endreswari