Leucaena glauca Benth.

Acacia glauca is an erect, unarmed shrub or small tree, 1-3(-5) m tall; crown open, branches many, terete, sparsely pubescent to glabrous, younger twigs more strigose; bark dark red. Leaves bipinnately or 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 x 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 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, membranous pod, oblong to strap-shaped, 1.5-10 cm x 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. Seeds ovoid to lenticular, brown. The generic name ‘acacia’ comes from the Greek word ‘akis’, meaning point or barb.

Flowering and fruiting may start as early as 6 months and flowering occurs throughout the year.

The shrub thrives on limestone and various other s.

A. glauca occurs in secondary vegetation, especially on limestone, but also on non-calcareous soils. It prefers dry climate and even grows where rainfall is as low as 200-500 mm and relative humidity 55-70 %. It performs poorly under low temperature and does not tolerate frost and shade.

A. glauca is native to tropical America where it is common in parts of southern Central America and the West Indies. It was introduced into Java in 1920 where it has become naturalized. It has been planted experimentally in the Philippines where it has also naturalized.

Propagation is by seed or by root suckers.

A. glauca extends itself by root suckers from the comparatively superficial root system. It can reach a height of about 3 m and diameter of 3 cm in 13 months. Growth is robust in the juvenile phase is often stronger than in Leucaena leucocephala but loses this advantage after 6 months. The plant tolerates heavy pruning.

It is generally free of diseases and pests.

There are 91 000 seeds/kg. Germination is irregular unless seeds are scarified or treated with hot water.

Erosion control: A. glauca is planted as a stabilizer of terrace ridges. Reclamation: It is mainly used to rehabilitate degraded and denuded lands. Soil improver: It performs very well on poor soils and in view of its unpalatability to livestock, its use as an alternative to L. leucocephala as a shrub legume deserves wider attention. Ornamental: The tree is a common ornamental throughout the tropics. Intercropping: It was originally planted as an undershrub in teak plantations in Indonesia.

Fodder: It is used as forage in Timor and seeds are fed to chicken in Java. It has been used as a host plant for the lac insect in Java. Analysis of Indonesian leaves gave 27% crude protein. Fuel: The wood is suitable for fuel. Timber: Wood is used for making household tools. Medicine: 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 in the Caribbean. A decoction of peeled branches with vinegar is taken as a cough remedy.