Taxonomy
Current name: Butea monosperma
Authority: (Lam.) Taub.
Family: Fabaceae - PapilionoideaeSynonym(s)
Butea frondosa Roxb. ex. Willd.
Erythrina monosperma Lam
Common names
(Bengali) : palas, polashi
(Marathi) : palash
(English) : bastard teak, flame-of-the-forest
(Hindi) : chalcha, chichra tesu, desuka jhad, dhak, palas
(Nepali) : dhak, palans, paras
(Sanskrit) : palasha
(Tamil) : parasa, parasu, porasum
Botanic description
Butea monosperma is a small to medium-sized deciduous tree, 5-15 (max. 20) m tall, up to 43 cm dbh; trunk usually crooked and tortuous, with rough greyish-brown, fibrous bark showing a reddish exudate; branchlets densely pubescent. Leaves trifoliate; petiole 7.5-20 cm long with small stipules; leaflets more or less leathery, lateral ones obliquely ovate, terminal one rhomboid-obovate, 12-27 x 10-26 cm, obtuse, rounded or emarginate at apex, rounded to cuneate at base, with 7-8 pairs of lateral veins, stipellate. Flowers in racemes, 5-40 cm long, near the top on usually leafless branchlets; calyx with campanulate tube and 4 short lobes; corolla 5-7 cm long, standard, wings and keel recurved, all about the same length, bright orange-red, more rarely yellow, very densely pubescent. Fruit an indehiscent pod, (min. 9) 17-24 x (min. 3) 4-6 cm, stalked, covered with short brown hairs, pale yellowish-brown or grey when ripe, in the lower part flat, with a single seed near the apex. Seed ellipsoid, flattened, about 3 cm long.
Natural Habitat
B. monosperma is a tree of tropical and subtropical climate. Found throughout the drier parts of India, often gregarious in forests, open grasslands and wastelands. It is a characteristic tree of the plains, often forming pure patches in grazing grounds and other open places, escaping extermination owing to its resistance to browsing and its ability to reproduce from seed and root suckers. In its native habitat, most of the rain is received during the monsoon season, while the autumn and summer months are generally dry. The tree is very drought resistant and frost hardy, although the leaves turn white and fall off.Geographic distributionNative : Cambodia, India, Indonesia, Japan, Laos, Myanmar, Nepal, Sri Lanka, Thailand, VietnamExotic : China, Papua New GuineaBiophysical limitsAltitude: Up to 1 500 m, Mean annual temperature: -4 -49 deg. C, Mean annual rainfall: 450-4500 mm Soil type: It grows on a wide variety of soils including shallow, gravelly sites, black cotton soil, clay loams, and even saline or waterlogged soils. Seedlings thrive best on a rich loamy soil with pH 6-7 under high temperature and relative humidity.Reproductive BiologyLeaves are shed during the dry season. At the beginning of the rainy season, the leafless tree flowers abundantly and is very conspicuous in the forest. At the end of the flowering period, new leaves develop, which are initially a pale bronze-tinged green. Birds are the chief pollinators.
Functional uses
Products
Fodder: In India, young leaves are good fodder, eaten mainly by buffaloes. Though the leaves are fairly rich in nutrients, digestibility values are low, comparable only to those of straws.
Fuel: Wood makes a fuel of moderate quality. Leaves are sometimes used as a fuel. The wood is burnt for gunpowder charcoal.
Fibre: A coarse fibrous material obtained from the inner bark is used for cordage, caulking the seams of boats and making paper.
Timber: The soft and not durable wood is light, about 570 kg/m³ air dry, white or yellowish-brown when fresh, but often turning greyish because of susceptibility to sap stain. It is not of great value but is sometimes used for utensils.
Gum or resin: A red exudate is obtained from the bark, hardening into a gum known as ‘butea gum’ or ‘Bengal kino’. It can be used as a dye and as tannin.
Tannin or dyestuff: A bright yellow to deep orange-red dye, known as butein, prepared from the flowers is used especially for dyeing silk and sometimes for cotton. This dye is used by Hindus to mark the forehead. The bark is used for tanning.
Lipids: The seeds yield a clear oil. Poison: Seeds show bactericidal and fungicidal activities. Medicine: The flowers are useful in the treatment of liver disorders and seeds act as an anthelmintic. An astringent gum oozing from the cut stem has medicinal properties as a powerful astringent and is applied in cases of diarrhoea. Other products: In India, the tree is an important host for the lac insect (Laccifer lacca), which produces shellac. Of all the lac trees, it yields the most lac stick per hectare.
