Acacia glauca (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Acacia glauca (L.) Moench

Protologue: Methodus: 446 (1794).

Family: Leguminosae - Mimosoideae

Chromosome number: 2n= 26

Synonyms

• Mimosa glauca L. (1753),
• Acacia villosa (Swartz) Willd. (1806), including forma glabra Backer (1963),
• Acaciella villosa (Swartz) Britton & Rose (1928).

Vernacular names

• Wild dividivi, redwood, wata pana (En). Acacia (Am).
• Amourette (Fr)
• Indonesia: mlanding sabrang, mlanding merah (Java), petes merah (West Timor).

Origin and geographic distribution

A. glauca originated in tropical America. It is common in parts of southern Central America and on many West Indian islands, in particular on Curaçao and Barbados. In 1920, A. glauca was introduced into Java, where it then naturalized, especially in the region of Yogyakarta. It has been planted experimentally in the Philippines, where it is said to have naturalized as well.

Uses

In Indonesia A. glauca was originally planted as an alternative undershrub to Leucaena leucocephala (Lamk) de Wit in teak plantations. At present, it is mainly used to rehabilitate degraded and denuded lands and as a stabilizer of terrace ridges. It is a common ornamental throughout the tropics.

The wood is suitable for fuel and for making household tools. A. glauca has been used as a host plant for the lac insect Laccifer lacca in East Java. In West Timor it is used as a forage, but it is generally reported for Java that goats and other livestock do not like it, although chicken eat the seeds.

In the Caribbean an infusion of the roots or leaves in vinegar and of the bark in water is used as a gargle to relieve sore throat and alleviate oral inflammations. A decoction of peeled branches with vinegar and sugar is taken as a cough medicine.

Properties

An analysis of dried leaves from Indonesian material gave per 100 g: crude protein 27 g, ether extract 4.8 g, non-digestible fibre 24 g, total phenolics 12.6 g, tannins 6 g. Weight of 1000 seeds is 11 g.

Botany

• Erect, unarmed shrub or small tree, 1-3(-5) m tall, with open crown and many dark red stems and branches. Root system tough and spreading, superficial. Branches terete, sparsely pubescent to glabrous, younger twigs more strigose.
• Leaves bipinnately (sometimes tripinnately) compound, pinnae in 2-10 pairs, 4-9 cm long, rachis 8-12 cm long, glandless; leaflets 10-30 pairs per pinna, opposite, oblong-lanceolate, 4-10 mm × 1-2 mm, unequal sided, base rounded, top blunt with acute tip, hairy to glabrescent; stipules lanceolate, early caducous.
• Inflorescence a short, sometimes subcapitate, 20-40-flowered spike, 2-6 together in the upper axils, the uppermost arranged in racemes; peduncle up to 2.5 cm long, pedicel 1-2 mm, articulated.
• Flowers 5-merous, bisexual, white turning yellowish; calyx campanulate, 0.5-1 mm long, 5-lobed; corolla tubular, 5-lobed, 2-4 mm long; stamens numerous, ovary stipitate with 5 mm long style.
• Fruit a flat, membranaceous pod, oblong to strap-shaped, 1.5-10 cm × 0.5-2 cm, stalk about 1 cm long, apiculate, glossy brown, 1-8-seeded, valves swollen where seeds develop, transversely veined along the margins.
• Seed ovoid to lenticular, brown.

A. glauca extends itself by root suckers from its comparatively superficial root system. In experiments in Indonesia comparing its performance with other fast-growing legumes, A. glauca was consistently among the fastest growing species, especially on very poor soils. It can reach a height of about 3 m and a stem diameter of 3 cm in 13 months from planting. Growth during the juvenile phase is often stronger than in Leucaena leucocephala ; after 6 months, however, it loses its advantage. Flowering and fruiting may start very early; in an experiment in Indonesia flowering started within 6 months from planting. It flowers throughout the year.

The habit of A. glauca is quite similar to the shrub forms of Leucaena leucocephala, but young twigs are more reddish and pods shorter and more rounded.

The synonymous name Acacia villosa is still very commonly used in South-East Asia. In 1753, Linnaeus described this species as Mimosa glauca. Later, however, he used this name for a species that is now known as Leucaena leucocephala, causing much confusion.

Ecology

A. glauca prefers a rather dry climate. It even grows well where mean annual rainfall is as low as 200-500 mm and the relative humidity 55-70%. In Indonesia, optimum rainfall is about 1200 mm/year in regions up to 1200 m altitude. It performs poorly under low temperature and does not tolerate frost.

A. glauca occurs in secondary vegetation, especially on limestone, but also on non-calcareous soils. On very poor soils it will grow better than L. leucocephala and most other legume species. It is less tolerant of shade than L. leucocephala, but reports of its tolerance of waterlogging are contradictory.

Agronomy

Propagation is by seed or by root suckers. Germination is irregular, unless seeds are scarified or treated with hot water. In the West Indies A. glauca spreads very easily and is never planted. Nevertheless, it has not become a noxious weed in Indonesia.

A. glauca tolerates heavy pruning and produces root suckers regularly. In comparison with L. leucocephala, it has a more superficial root system and produces fewer leaves. A. glauca is generally free of diseases and pests.

Genetic resources and breeding

It is unlikely that any substantial germplasm collections are being maintained and there are no known breeding programmes.

Prospects

Observations over many years and experimental results in Indonesia and the Philippines indicate that A. glauca is a very useful undershrub in forest plantations, a shrub legume in agroforestry and a species to rehabilitate degraded soils. In view of its good performance on very poor soils and its unpalatibility to livestock, its use as an alternative to Leucaena leucocephala deserves wider attention.

Literature

• Danimihardja, S., Saefudin, Syarif, F. & Setyowati-Indarto, N., 1988. Pertumbuhan beberapa jenis Leguminosa tumbuh cepat di lapangan setelah semainya diinokulasi dengan Rhizobium [The growth of some fast-growing legume species in the field after seedling inoculation with Rhizobium]. Berita Biologi 3(8): 377-381.
• de Wit, H.C.D., 1961. Typification and correct names of Acacia villosa Willd. and Leucaena glauca (L.) Bth. Taxon 10: 50-54.
• Dirdjosoemarto, S., 1981. The performance of some small tree legumes on eroded lands at Wanagama experimental forest. In: Wiersum, K.F. (Editor): Observations on agroforestry on Java. Gadjah Mada University, Yogyakarta, Indonesia and Agricultural University, Wageningen, the Netherlands. pp. 90-96.
• Nielsen, I.C., 1992. Mimosaceae (Leguminosae - Mimosoideae). Acacia. In: de Wilde, W.J.J.O., Nooteboom, H.P. & Kalkman, C. (Editors): Flora Malesiana. Series 1, Vol. 11. Foundation Flora Malesiana, Leiden, the Netherlands. pp. 34-64, 208.
• Riyanto, T.W., 1979. Perbandingan pertumbuhan lamtoro dan mlanding sabrang pada beberapa kondisi tanah [Comparison between the growth of Leucaena leucocephala and Acacia villosa under different soil conditions]. Duta Rimba 5(33): 3-6.
• Rudjiman, 1981. Multiple-purpose species for planting on critical soils on Java. In: Wiersum, K.F. (Editor): Observations on agroforestry on Java. Gadjah Mada University, Yogyakarta, Indonesia and Agricultural University, Wageningen, the Netherlands. pp. 81-83.
• Serrano, R.C., 1988. Alternatives to ipil-ipil for agroforestry. Philippine Council for Agriculture, Forestry and Natural Resources Research & Development (PCARRD) Monitor 16(3): 1, 10.

Authors

J. Jukema & S. Danimihardja