Bombax ceiba (Hindi name - Semal or Shalmali) grows to an average of 20 meters, with old trees up to 60 meters in wet tropical weather. This tree has a straight trunk and its leaves are deciduous in winter. Red flowers with 5 petals appear in the spring before the new foliage. It produces a capsule which, when ripe, contains white fibres like cotton. Trees from seeds begin flowering when 8 to 10 feet tall, and can reach 30 feet in five years.

Although its stout trunk suggests that it is useful for timber, its wood is too soft to be very useful. It is easy to work but not durable anywhere other than under water. So it is popular for construction work, but is very good and prized for manufacture of plywood, match boxes and sticks, scabbards, patterns, moulds, etc. Also for making canoes and light duty boats and or other structures required under water.

Semul trees bear beautiful red-colored flowers during January to March when the tree is deciduous.  The flowers are 6 to 7 inches long and are up to 7 inches wide. They are borne solitary or in clusters at or near the ends of the branches. The flower consist of five satiny, red, scarlet, or sometimes white petals. The fruit, a ball like structure, on maturity appears during March and April. These are full of cotton-like fibrous stuff. It is for the fiber that villagers gather the semul fruit and extract the cotton substance called "kopak". This substance is used for filling economically priced pillows, quilts, sofas etc. The fruit is cooked and eaten and also pickled.
 
The roots are used in the treatment of diarrhea, dysentery, menorrhagia, styptic and for wounds. The gum is useful in dysentery, hemoptysis, pulmonary tuberculosis, influenza, burning sensation, menorrhagia and enteritis. Bark is used for healing wounds and to stop bleeding. Flowers are astringent and good for skin troubles and haemorrhoids. Seeds are useful in treating gonorrhea and chronic cystitis. Young fruits are useful in calculus affections, chronic inflammations and ulceration of bladder and kidney.