This genus (Linaceae) contains 200 species of annuals, biennials, perennials, subshrubs and shrubs, some of which are evergreen, and distributed widely in temperate regions. There are several ornamental species, which are grown for their profusely blooming, five-petalled flowers, which can be yellow, white, blue, red or pink. They are useful plants in a rock garden or border.
They are mostly quite frosting and hardy. Some species need shelter in cool climates. Grow in a sunny spot in humus-rich, well-drained, peaty soil. After perennial species flower, prune them back hard. Propagate the annuals, biennials as well as perennials from seed in autumn and perennials by division in spring or fall. Most self-sow readily. Transplanting can be conducted from late fall until early spring.
Linum arboreum
From the northern hemisphere, this sticky stemmed shrub grows to twelve inches and has whorls of one inch. It has spatula-shaped leaves and produces compact heads of yellow flowers.
Linum campanulatum
This small southern European perennial is reminiscent of some of the oxalises or of California poppy (Eschscholzia california). It has small, slightly glaucous leaves and during summer, it produces three to five flowered heads of yellow to orange flowers.
Linum capitatum
This European rhizomatous perennial grows to about eighteen inches high. It forms a basal clump of foliage from which emerge leafy flower stems bearing heads of five or more flowers during the flowering stage.
Linum flavum
It is commonly called golden flax or yellow flax. It is a tall woody perennial flax that can grow up to twenty-four inches. This southern European species has dark green, pointed or blunt-ended leaves about one inch long. The flowering period for golden flax will be in the summer in which it produces clumps of golden-yellow and trumpet-shaped flowers.Linum flavum ‘Compactum’ is a dwarf variety growing from six to eight inches tall.
Linum ‘Gemmell/s Hybrid’
This semi-evergreen perennial grows to six inches and has gray-tinted, ovate leaves and yellow flowers that are borne profusely throughout summer.
Linum grandiflorum
This flowering flax is native to Algeria, this annual has small, rounded, flattish, pink to red flowers as well as lance-shaped and gray-leaves. The optimal flowering period is observed in cool summers. This has a slim, erect habit and is fairly fast growing to eighteen inches. ‘Rubrum’ has deeper crimson-red flower.
Linum narbonense
This species is commonly known as blue flaxes, which has violet and funnel-shaped flowers borne on slender stems. It has soft green leaves which form clumps and canopy that are eighteen inches high and wide. It is a perennial species that are natives of the Mediterranean region. The flowering period may last for many weeks in the summer.
Linum perenne
This species is also known as Linum sibiricum is widely found in Europe and temperate Asia. This perennial species produces a vigorous growth with shapely and bushy canopy 24 inches high and 12 inches wide. It has slender stems with grass-like leaves and clusters of open, funnel-shaped, light blue flower are borne throughout the summer. ‘Alba’ is a pure white form.
Linum usitatissimum
Flax is one of the oldest cultivated crops and is a pivotal fiber plant species that is believed to originate from the Mediterranean. Linseed flax grows up to 40 to 60 centimeter tall with highly branched stems. It is widely grown for oil (one of the most important oilseed crop), fiber, and food. It is also known as linseeds. The only differences between flaxseeds and linseeds are flaxseeds are tiny, edible seeds, whereas linseeds are the hulled version of the same seed.
Linseeds are also known as brown or golden flaxseeds. Linseed is the more commonly known edible seed that generates invaluable oil.
On the other hand, flaxseed is a textile that can be further processed and weaved into linen, strong ropes or fishing nets.
The seed is oblong and flattened. It comprises an embryo with two cotyledons surrounded by a thin endosperm while the color of the seed coat varies. The seed is composed of 41% of fat, 20% protein, 28% total dietary fiber, 7.7% moisture, and 3.4% ash. In addition, it consists of cyanogenic glycosides, phytic acid, phenolics, trypsin inhibitors, linatine, lignans, minerals, vitamins, cadmium, selenium, and cyclolinopeptides. Linseed protein contains higher amounts of arginine, aspartic acid, and glutamic acid than other amino acids.
The linseed oil can be found in cotyledons that is an excellent source of the omega-3 fatty acid linolenic acid. With the great source of omega-3 fatty acid, linseed is widely consumed as a nutritional and functional food worldwide. The high percentage (38 to 44%) of it in linseed oil makes it an ideal material for paints, varnishes, and inks due to its fast polymerization properties. It may lower total cholesterol levels, which is good for the heart and circulatory system. On top of that, the oil can be consumed as a dietary supplement to resolve sun-sensitive issue or eczema. Apart from that, it was found that Indian farmers used to apply linseed oil on the surface of iron tools as a protective coating against rust, as well as on wooden materials, for shine and longevity.
It is a rich source of dietary fiber both soluble as well as insoluble fibers. In addition, flaxseed acts as a lubricant and an extraordinary source of fiber, which helps to lower the risk of constipation. It exhibits a natural laxative effect of dietary fiber. Flaxseed mucilage associated with the hull of flaxseed is a gum such as material composed of acidic and neutral polysaccharides.
Additionally, linseed can be processed into linseed tea that is used as a demulcent in cough especially those that form to irritation of the pharynx and upper part of the respiratory passage. The waste of the downstream product can be further utilized as brown seedcakes. The linseed cake is a material that contains about 3 % oil and 24-28 % protein, which has been used only marginally for animal feeding.
Studies found that flaxseeds possess several medicinal and pharmaceutical properties such as anti-inflammatory, anti-arrhythmic, anti-ulcer, anti-diabetic, and antioxidant properties. The research found that flaxseed fiber plays a pivotal role in lowering blood glucose levels.
Further reading:
Basch, E., Mphil, S. B., Collins, J., Dacey, C., Harrison, M., & Szapary, P. (2007). Flax and flaxseed oil (Linum usitatissimum): a review by. J Soc Integr Oncol, 5(3), 92-105.
Belonogova, M., & Raldugina, G. (2007). Biotechnology of flax (Linum usitatissimum). Functional Plant Science and Biotechnology. Global Science Books, 327-346.
Casa, R., Russell, G., Cascio, B. L., & Rossini, F. (1999). Environmental effects on linseed (Linum usitatissimum L.) yield and growth of flax at different stand densities. European journal of agronomy, 11(3-4), 267-278.
Dixit, S., & Rehman, A. (2012). Linseed oil as a potential resource for bio-diesel: a review. Renewable and Sustainable Energy Reviews, 16(7), 4415-4421.
Doreau, M., & Ferlay, A. (2015). Linseed: a valuable feedstuff for ruminants. Ocl, 22(6), D611.
Green, A. G., & Marshall, D. R. (1981). Variation for oil quantity and quality in linseed (Linum usitatissimum). Australian Journal of Agricultural Research, 32(4), 599-607.
Gutte, K. B., Sahoo, A. K., & Ranveer, R. C. (2015). Bioactive components of flaxseed and its health benefits. International Journal of Pharmaceutical Sciences Review and Research, 31(1), 42-51.
Hall, L. M., Booker, H., Siloto, R. M., Jhala, A. J., & Weselake, R. J. (2016). Flax (Linum usitatissimum L.). In Industrial oil crops (pp. 157-194). AOCS Press.
Hussain, M. S., Kaur, G., & Mohapatra, C. (2021). Nutritional composition and functions of flaxseed (Linum usitatissimum linn.). Food Ther Health Care, 3(4), 88-91.
Jhala, A. J., & Hall, L. M. (2010). Flax (Linum usitatissimum L.): current uses and future applications. Aust. J. Basic Appl. Sci, 4(9), 4304-4312.
Zuk, M., Richter, D., Matuła, J., & Szopa, J. (2015). Linseed, the multipurpose plant. Industrial Crops and Products, 75, 165-177.