Common names
Amharic(temar); Arabic(tamar hindi); Bengali(amil,balati,dekhani babul); Burmese(kway-tanyeng); English(blackbead tree,bread and cheese tree,madras thorn,manila tamarind,quamachil,sweet Inga,vilayati chinch); Filipino(damortis,kamanchilis,kamatsile); Hawaian(opiuma); Hindi(dakhani babul,imli,jangal jelbi,jangle jalebi,vilayati babul,vilayati imli); Indonesian(asam koranji); Javanese(asam belanda,asem londo); Khmer(âm’pül tük); Lao (Sino-Tibetan)(khaam th’ééd); Malay(asam kranji,asam tinja); Spanish(guama americano,guamuchil,madre de flecha,quamachil); Swahili(maramata,mkwaju wa kihindi); Tamil(kodukapuli,kodukkaapuli); Thai(makham-khong,makham-that); Tigrigna(temri-hindi); Vietnamese(keo tây,me keo)

Synonyms
Acacia obliquifolia Mart. & Gall.
Inga dulcis (Roxb.) Willd.
Inga leucantha K. Presl
Mimosa dulcis Roxb.
Mimosa monilifera Bert.
Pithecellobium littorale Britton & Rose ex Record

Botany
The height of Pithecelobium dulce is commonly 10-15 m, but ranges from 5-18 m. Crown is broad spreading with irregular branches up to 30m across; bole short, up to 1 m thick. The bark is grey, becoming rough, furrowed, and eventually peeling.

Leaves are bipinnate, with 2 pairs of 2 kidney-shaped leaflets each 2-2.5 x 1-2 cm, rather resembling Hardwickia binnata. New leaf growth coincides with the loss of old leaves, giving the tree an evergreen appearance. Thin spines are in pairs at the base of leaves, and range from 2 to 15 mm in length.

The flowers are in small white heads 1 cm in diameter. Each flower has a hairy corolla and calyx surrounding about 50 thin stamens united in a tube at the base.

Pods are 10-15 x 1.5 cm; the colour becoming spiral and reddish-brown as they ripen. Each pod contains 5-10 shiny black seeds up to 2 cm long. The grey bark and tightly-coiled seed pods are characteristic of this tree, and make it easy to distinguish.

The genus is often written as Pithecollobium or Pithecolobium. The genus name is derived from the greek words pithekos (an ape) and lobos (a lobe), alluding to the pods, shaped like the human ears. This species was named and described botanically in 1795 from Coromandel, India, where it had been introduced. The specific name, meaning sweet, doubtless refers to the edible seed pulp.

Domestication
P. dulce originates from Mexico and Central America. The Portuguese traders introduced it to Indonesia and the Spaniards to the Philippines; it is also common in Malaysia and Thailand. It has been naturalized throughout the tropics such as India, Philippines, Tanzania and other coastal regions of tropical Africa.

Ecology
P. dulce is not exacting in its climatic requirements and grows well at low and medium altitudes in both wet and dry areas under full sunlight. It is a strong light demander, but can stand a considerable shade. Generally found in the plains, it can also survive in undulating terrain. P. dulce can grow on poor soils, on wastelands and even with its roots in brackish water. It is a drought resistant species but susceptible to frost, coming up well in areas of low rainfall due to its extensive root system.

Biophysical limits
Altitude: 900-1 800 m, Mean annual temperature: 0-48 deg. C, Mean annual rainfall: 250-1 650 mm

Soil type: P. dulce is found on most soil types including clay, limestone, and wet sand with a brackish watertable. The tree is rated highly tolerant to soil salinity and impoverished soils. It however grows best on well-drained, deep, fertile loamy agricultural soils.

Native Range
Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Mexico, Paraguay, Peru, Surinam, United States of America, Uruguay, Venezuela

Exotic Range
Cambodia, China, Cuba, Eritrea, Ethiopia, Haiti, India, Indonesia, Jamaica, Kenya, Laos, Malaysia, Myanmar, Philippines, Puerto Rico, Reunion, Sudan, Tanzania, Thailand, Vietnam, Virgin Islands (US), Zanzibar

Reproductive Biology
In the Philippines they flower from October to November and bear mature fruits in abundance during January and February; in west Java bloom is between April and June and the pods ripen 2-3 months later, from June to August.

Propagation Methods
Natural reproduction comes up adequately in favourable localities; it occurs freely from self-seeding, especially around the margins of cultivated fields where plentiful seeding can be found under mature trees.
Plants yield viable seeds at an early age. The ripe pods are collected and dried in the sun, till they dehisce. Unbroken pods are thrashed to extract the seed, winnowed and cleaned. No pre-treatment is required; and soaking actually reduces germination and heating kills the seeds. Direct sowing is successful. The plants are best propagated by transplants in the nursery. The seeds are either broadcast in the raised nursery beds, or in the polythene bags, soon after collection. The beds must have well-pulverized soil and organic manure and be profusely watered. Germination commences from 7-10 days, and is completed in 2-3 weeks. Seedlings may be pricked out from the germination beds to transplant beds or in polythene bags after 6 months. Young plants need the shelter from dry and hot winds. They are taken out with a ball of earth when about a year old.
Manila tamarind can also be readily established by branch-cuttings.

Tree Management
The species is fast growing; trees reach a height of 12-15 m and a girth of 0.91-1.2 m in about 40 years. In favourable soil conditions, it may reach a height of 10 m in 5-6 years. It coppices vigorously and produces root suckers upon injury to roots. The tree can stand considerable amount of pruning, lopping and nibbling by sheep and goats. It also competes with weeds and outgrows fast.

Germplasm Management
Seed storage behaviour is recalcitrant. The seeds weigh 6 460-6 700/kg.

Products
Food: Pods contain a pulp that is variously sweet and acid, commonly white but also red. The seed and pulp are made into a sweet drink similar to lemonade and also eaten roasted or fresh. The seeds are used fresh in curries in India. In Mexico, Cuba and Thailand, the pods are harvested and are customary sold on roadside stands.

Fodder: The pods and leaves gathered from hedge clippings are devoured by all livestock; horses, goats, camels, cattle and sheep. The presscake residue from seed oil extraction may be used as stock feed.

Apiculture: Flowers are visited by bees and yield good quality honey.

Fuel: Fast-growing and coppices vigorously but due to its smokiness and low calorific value (5 177-5 600 kcal/kg), P. dulce wood is not of very high quality. In parts of India, it is planted and harvested to fuel brick kilns.

Timber: Sapwood is yellowish, and heartwood yellowish or reddish-brown. The wood of P. dulce is strong and durable yet soft and flexible. It is moderately hard and usually straight grained. It weighs about 590 kg/m³, is easy to saw and finishes to a smooth surface. In south India, it is used to make drums, while in China, it is said to be used for matches. It can be used in construction and for posts. The short spines and irregular, crooked growth make it less attractive for wood uses.

Gum or resin: The wounded bark exudes a mucilaginous reddish-brown gum somewhat like gum arabic.

Tannin or dyestuff: Tannin, used to soften leather, can be extracted from the bark (about 25%), seeds and leaves; the bark is also used to dye fishnets a yellow colour.

Lipids: Seeds contain a greenish oil (20%), which, after refining and bleaching, can be used for food or in the making of soap and can substitute kapok and ground nut seed oils.

Medicine: In Haiti root and bark decoctions are taken orally against diarrhoea; fruit pulp is taken orally to stop blood flow in case of heamoptysis. The seed juice is inhaled into the nostrils against chest congestion and pulverised seeds are ingested for internal ulcers. The leaves, when applied as a plaster, can allay pain of venereal sores and taken with salt can cure indigestion, but can also produce abortion. The root bark may be used to cure dysentery. The bark is used medicinally as a ferbrifuge.

Services
Shade or shelter: The tree is extensively planted for its dense shade.

Reclamation: Since it can grow on waste and denuded lands, P. dulce can afforest and conserve poor soils.

Nitrogen fixing: P. dulce forms root nodules with Rhizobium bacteria. Nodulation is common in all types of soil, but quantitative data on fixation has not been reported.

Ornamental: Very popular as an ornamental and is used in topiary (plant sculpturing). Trees with variegated leaflets are available as ornamental pot plants in Hawaii.

Boundary or barrier or support: With regular trimming, P. dulce makes a dense, almost impenetrable thorny hedge that keeps out livestock and forms useful shelter belts; for hedges, seeds may be sown in 2 rows of 15 x 30 cm.

Further Reading
Anon. 1986. The useful plants of India. Publications & Information Directorate, CSIR, New Delhi, India.