Flax linseed oil and linen fibre producing annual herbaceous plant (Linum usitatissimum) grown in many temperate and subtropical countries. This cultivated variety probably originated from the wild flax, L. angustifolium in prehistoric times. Egyptians used to make linen cloth from flax fibres.
The plants grow to a height of 30 to 80 cm, with a distinct main stem and a short taproot. Each flower has five petals that are blue, white or pale pink and ten anthers that are blue or yellow. The flowers open in early morning and shed their petals by early afternoon. The shiny, flattened seeds are brown or yellow and about one cm. The linen or bast fibres occur in the bark of the stem.
Flax grows well in medium loam or clay soils. It is harvested for fibre after about 100 days following sowing, when about 50% of the seeds are ripe. The dried stalks, when dried, deseeded by threshing or beating the tops at the bundles. The seed is collected for sowing purposes, oil extraction or feed.
The deseeded straw is then retted by submergence in water for 7-21 days, when the bark of the stem is loosened so that it can be readily peeled from the woody core. After the fibre is separated from the woody core the straw is set to dry for further use.
Each capsule of flax produces 40-50 light brown flat, oval, shiny smooth seeds. Oil colour varies from yellow to brownish. In Bangladesh the plant is cultivated as rabi crop mostly in the districts of Khulna, Jessore, Dinajpur, Kushtia, Pabna, Dhaka, Mymensingh, Tangail and Faridpur. About 49,000 m tons of seed are produced annually from about 73,000 ha of land. The seed yields 30-38% oil containing about 20% protein. The oil is used as an ingredient of paint, varnish, etc. It is also used in artificial hide and in the ink for printing. Flax fibre has limited use in Bangladesh. [Mostafa Kamal Pasha]