Flax flower (Linum)

Flax (Linum usitatissimum), also known as common flax or linseed, is a member of the genus Linum in the family Linaceae.
It is a food and fiber crop cultivated in cooler regions of the world.
The textiles made from flax are known in the Western countries as linen, and traditionally used for bed sheets, underclothes, and table linen. The oil is known as linseed oil. In addition to referring to the plant itself, the word "flax" may refer to the unspun fibers of the flax plant.
The plant species is known only as a cultivated plant, and appears to have been domesticated just once from the wild species Linum bienne, called pale flax.

Several other species in the genus Linum are similar in appearance to L. usitatissimum, cultivated flax, including some that have similar blue flowers, and others with white, yellow, or red flowers. Some of these are perennial plants, unlike L. usitatissimum, which is an annual plant.

Cultivated flax plants grow to 1.2 m (3 ft 11 in) tall, with slender stems. The leaves are glaucous green, slender lanceolate, 20–40 mm long, and 3 mm broad.

The flowers are pure pale blue, 15–25 mm in diameter, with five petals. The fruit is a round, dry capsule 5–9 mm in diameter, containing several glossy brown seeds shaped like an apple pip, 4–7 mm long.

Flax is grown for its oil, used as a nutritional supplement, and as an ingredient in many wood-finishing products. Flax is also grown as an ornamental plant in gardens. Flax fibers are used to make linen. The Latin species name usitatissimum means "most useful".

Flax fibers are taken from the stem of the plant, and are two to three times as strong as those of cotton. Additionally, flax fibers are naturally smooth and straight. Europe and North America depended on flax for vegetable-based cloth until the nineteenth century, when cotton overtook flax as the most common plant used for making rag-based paper. Flax is grown on the Canadian prairies for linseed oil, which is used as a drying oil in paints and varnishes and in products such as linoleum and printing inks. In India, flax seed oil also is known as alsi in Hindi and javas in Marathi. It is mainly used in Savji curries, such as mutton curries.

Linseed meal, the by-product obtained after oil production from flax seeds, is used to feed livestock. It is a protein-rich feed for ruminants, rabbits and fish.

Flaxseeds occur in two basic varieties: brown and yellow or golden (also known as golden linseeds).
Most types have similar nutritional characteristics and equal numbers of short-chain omega-3 fatty acids. The exception is a type of yellow flax called solin (trade name Linola), which has a completely different oil profile and is very low in omega-3 FAs. Flaxseeds produce a vegetable oil known as flaxseed oil or linseed oil, which is one of the oldest commercial oils. It is an edible oil obtained by expeller pressing, sometimes followed by solvent extraction. Solvent-processed flaxseed oil has been used for many centuries as a drying oil in painting and varnishing.

Although brown flax may be consumed as readily as yellow, and has been for thousands of years, its better-known uses are in paints, for fiber, and for cattle feed.

Flaxseed sprouts are edible, with a slightly spicy flavor. Excessive consumption of flaxseeds with inadequate amounts of water may cause bowel obstruction. In northern India, flaxseed, called tisi or alsi, traditionally is roasted, powdered, and eaten with boiled rice, a little water, and a little salt.

Whole flaxseeds are chemically stable, but ground flaxseed may go rancid when left exposed to air at room temperature in as little as one week because of oxidation. Refrigeration and storage in sealed containers will keep ground flax from becoming rancid for a longer period. Under conditions similar to those found in commercial bakeries, trained sensory panelists could not detect differences between bread made with freshly ground flax and bread made with milled flax that had been stored for four months at room temperature. If packed immediately without exposure to air and light, milled flax is stable against excessive oxidation when stored for nine months at room temperature and under warehouse conditions, for twenty months at ambient temperatures.

Three natural phenolic glucosides, secoisolariciresinol diglucoside, p-coumaric acid glucoside, and ferulic acid glucoside, can be found in commercial breads containing flaxseed.

Flax fiber is extracted from the bast beneath the surface of the stem of the flax plant. Flax fiber is soft, lustrous, and flexible; bundles of fiber have the appearance of blonde hair, hence the description "flaxen" hair. It is stronger than cotton fiber, but less elastic. The best grades are used for linen fabrics such as damasks, lace, and sheeting. Coarser grades are used for the manufacturing of twine and rope, and historically, for canvas and webbing equipment. Flax fiber is a raw material used in the high-quality paper industry for the use of printed banknotes, rolling paper for cigarettes, and tea bags.

The use of flax fibers dates back tens of thousands of years; linen, a refined textile made from flax fibers, was worn widely by Sumerian priests more than 4,000 years ago. Industrial-scale flax fiber processing existed in antiquity. A bronze-age factory dedicated to flax processing was discovered in Euonymeia.

Flaxseed and its oil have repeatedly been demonstrated to be nontoxic and are generally recognized as safe for human consumption.
Like many common foods, flax contains small amounts of cyanogenic glycoside; these are nontoxic when consumed in typical amounts, but may be toxic when consumed in large quantities of such staple foods such as cassava. Typical concentrations (for example, 0.48% in a sample of defatted dehusked flaxseed meal) can be removed by special processing.

The soils most suitable for flax, besides the alluvial kind, are deep loams containing a large proportion of organic matter. Flax is often found growing just above the waterline in cranberry bogs. Heavy clays are unsuitable, as are soils of a gravelly or dry sandy nature. Farming flax requires few fertilizers or pesticides. Within eight weeks of sowing, the plant can reach 10–15 cm (3.9–5.9 in) in height and grows several centimeters per day under its optimal growth conditions, reaching 70–80 cm (28–31 in) within 50 days.

Flax is harvested for fiber production after about 100 days, or a month after the plants flower and two weeks after the seed capsules form. The bases of the plants begin to turn yellow. If the plants are still green, the seed will not be useful, and the fiber will be underdeveloped. The fiber degrades once the plants turn brown.

Flax grown for seed is allowed to mature until the seed capsules are yellow and just starting to split; it is then harvested in various ways. A combine harvester may either cut only the heads of the plants, or the whole plant. These are then dried to extract the seed. The amount of weeds in the straw affects its marketability, and this, coupled with market prices, determines whether the farmer chooses to harvest the flax straw. If the flax straw is not harvested, typically, it is burned, since the stalks are quite tough and decompose slowly (i.e., not in a single season). Formed into windrows from the harvesting process, the straw often clogs up tillage and planting equipment. Flax straw that is not of sufficient quality for fiber uses can be baled to build shelters for farm animals, or sold as biofuel, or removed from the field in the spring.