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103-648: Munsterland, the area of land that straddles the German-Dutch border, was known for cotton. The soil was not fertile and from the 16th century additional income was gained from flax production to make linen , which was woven into a rough sail cloth . By the 19th century, Bocholt was producing fustian (tree silk), a compound cloth of linen warp and cotton weft . This was exported. The textile merchants then established cotton mills that exploited these skills and trade links. Egbert Jannink set up his factory on another site in 1810. It expanded and moved to this site in

206-590: A drying oil in painting and varnishing. Although brown flax seed varieties may be consumed as readily as the yellow ones, and have been for thousands of years, these varieties are more commonly used in paints, for fiber, and for cattle feed. A 100-gram portion of ground flax seed supplies about 2,234 kilojoules (534 kilocalories) of food energy , 41 g of fat, 28 g of fiber, and 20 g of protein. Whole flax seeds are chemically stable, but ground flax seed meal, because of oxidation , may go rancid when left exposed to air at room temperature in as little as

309-461: 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, reaching 70–80 cm (28–31 in) within 50 days. In 2022, world production of raw or retted flax was 875,995 tonnes , led by France with 75% of the total. One of the largest regions in France for flax production

412-504: A nutritional supplement and as an ingredient in many wood-finishing products. Flax is also grown as an ornamental plant in gardens. Moreover, flax fibers are used to make linen . The specific epithet in its binomial name, usitatissimum, means "most useful". Flax fibers taken from the stem of the plant are two to three times as strong as cotton fibers. Additionally, flax fibers are naturally smooth and straight. Europe and North America both depended on flax for plant-based cloth until

515-449: A pigment binder in oil paints , as a plasticizer and hardener in putty , and in the manufacture of linoleum . Linseed oil use has declined over the past several decades with increased availability of synthetic alkyd resins—which function similarly but resist yellowing. Flax seed and its oil are generally recognized as safe for human consumption. Like many common foods, flax contains small amounts of cyanogenic glycoside , which

618-725: A textile comes from the present-day Republic of Georgia , where spun, dyed, and knotted wild flax fibers found in Dzudzuana Cave date to the Upper Paleolithic , 30,000 years ago. Humans first domesticated flax in the Fertile Crescent region. Evidence exists of a domesticated oilseed flax with increased seed-size from Tell Ramad in Syria and flax fabric fragments from Çatalhöyük in Turkey by c.  9,000 years ago. Use of

721-485: A BMI greater than 27. Another meta-analysis showed that consumption of flax seeds for more than 12 weeks produced small reductions in systolic blood pressure and diastolic blood pressure . A third showed that consuming flax seed or its derivatives may reduce total and LDL-cholesterol in the blood, with greater benefits in women and people with high cholesterol . A fourth showed a small reduction in c-reactive protein (a marker of inflammation) only in persons with

824-510: A body mass index greater than 30. Linseed oil , also known as flaxseed oil or flax oil (in its edible form), is a colourless to yellowish oil obtained from the dried, ripened seeds of the flax plant ( Linum usitatissimum ). The oil is obtained by pressing , sometimes followed by solvent extraction . Owing to its polymer-forming properties, linseed oil is often blended with combinations of other oils, resins or solvents as an impregnator, drying oil finish or varnish in wood finishing , as

927-405: A combine then harvests the seeds similar to wheat or oat harvesting. The plant is pulled up with the roots (not cut), so as to increase the fiber length. After this, the flax is allowed to dry, the seeds are removed, and it is then retted . Dependent upon climatic conditions, characteristics of the sown flax and fields, the flax remains on the ground between two weeks and two months for retting. As

1030-408: A decussate pattern, in which each node rotates by 1/4 (90°) as in the herb basil . The leaves of tricussate plants such as Nerium oleander form a triple helix. The leaves of some plants do not form helices. In some plants, the divergence angle changes as the plant grows. In orixate phyllotaxis, named after Orixa japonica , the divergence angle is not constant. Instead, it is periodic and follows

1133-757: A further disadvantage, because this fatty acid oxidises and goes rancid quickly, which shortens the storage time. Linola was developed in Australia and introduced in the 1990s with less omega-3, specifically to serve as fodder . Another disadvantage of the meal and seed is that it contains a vitamin B6 ( pyridoxine ) antagonist, and may require this vitamin be supplemented, especially in chickens , and furthermore linseeds contain 2–7% of mucilage (fibre), which may be beneficial in humans and cattle, but cannot be digested by non-ruminants and can be detrimental to young animals, unless possibly treated with enzymes . Linseed meal

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1236-551: A percentage of total fat , flax seeds contain 54% omega-3 fatty acids (mostly ALA ), 18% omega-9 fatty acids ( oleic acid ), and 6% omega-6 fatty acids ( linoleic acid ); the seeds contain 9% saturated fat , including 5% as palmitic acid . Flax seed oil contains 53% 18:3 omega-3 fatty acids (mostly ALA) and 13% 18:2 omega-6 fatty acids. A meta-analysis showed that consumption of more than 30 g of flax-seed daily for more than 12 weeks reduced body weight, body mass index (BMI), and waist circumference for persons with

1339-504: A petiole like structure. Pseudopetioles occur in some monocotyledons including bananas , palms and bamboos . Stipules may be conspicuous (e.g. beans and roses ), soon falling or otherwise not obvious as in Moraceae or absent altogether as in the Magnoliaceae . A petiole may be absent (apetiolate), or the blade may not be laminar (flattened). The petiole mechanically links the leaf to

1442-463: A plant matures; as a case in point Eucalyptus species commonly have isobilateral, pendent leaves when mature and dominating their neighbors; however, such trees tend to have erect or horizontal dorsiventral leaves as seedlings, when their growth is limited by the available light. Other factors include the need to balance water loss at high temperature and low humidity against the need to absorb atmospheric carbon dioxide. In most plants, leaves also are

1545-419: A regular organization at the cellular scale. Specialized cells that differ markedly from surrounding cells, and which often synthesize specialized products such as crystals, are termed idioblasts . The epidermis is the outer layer of cells covering the leaf. It is covered with a waxy cuticle which is impermeable to liquid water and water vapor and forms the boundary separating the plant's inner cells from

1648-401: A result of alternating rain and the sun, an enzymatic action degrades the pectins which bind fibers to the straw. The farmers turn over the straw during retting to evenly rett the stalks. When the straw is retted and sufficiently dry, it is rolled up. It is then stored by farmers before extracting the fibers. Threshing is the process of removing the seeds from the rest of the plant. Separating

1751-475: A scaffolding matrix imparting mechanical rigidity to leaves. Leaves are normally extensively vascularized and typically have networks of vascular bundles containing xylem , which supplies water for photosynthesis , and phloem , which transports the sugars produced by photosynthesis. Many leaves are covered in trichomes (small hairs) which have diverse structures and functions. The major tissue systems present are These three tissue systems typically form

1854-541: A severe dry season, some plants may shed their leaves until the dry season ends. In either case, the shed leaves may be expected to contribute their retained nutrients to the soil where they fall. In contrast, many other non-seasonal plants, such as palms and conifers, retain their leaves for long periods; Welwitschia retains its two main leaves throughout a lifetime that may exceed a thousand years. The leaf-like organs of bryophytes (e.g., mosses and liverworts ), known as phyllids , differ heavily morphologically from

1957-415: A similar oil profile to brown flax seeds and both are very high in omega-3s ( alpha-linolenic acid (ALA), specifically). Flax seeds produce a vegetable oil known as flax seed oil or linseed oil , which is one of the oldest commercial oils. It is an edible oil obtained by expeller pressing and sometimes followed by solvent extraction . Solvent-processed flax seed oil has been used for many centuries as

2060-402: A single (sometimes more) primary vein in the centre of the leaf, referred to as the midrib or costa, which is continuous with the vasculature of the petiole. The secondary veins, also known as second order veins or lateral veins, branch off from the midrib and extend toward the leaf margins. These often terminate in a hydathode , a secretory organ, at the margin. In turn, smaller veins branch from

2163-573: A single leaf grows from each node, and when the stem is held straight, the leaves form a helix . The divergence angle is often represented as a fraction of a full rotation around the stem. A rotation fraction of 1/2 (a divergence angle of 180°) produces an alternate arrangement, such as in Gasteria or the fan-aloe Kumara plicatilis . Rotation fractions of 1/3 (divergence angles of 120°) occur in beech and hazel . Oak and apricot rotate by 2/5, sunflowers, poplar, and pear by 3/8, and in willow and almond

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2266-523: A single point. In evolutionary terms, early emerging taxa tend to have dichotomous branching with reticulate systems emerging later. Veins appeared in the Permian period (299–252 mya), prior to the appearance of angiosperms in the Triassic (252–201 mya), during which vein hierarchy appeared enabling higher function, larger leaf size and adaption to a wider variety of climatic conditions. Although it

2369-409: A small leaf. Stipules may be lasting and not be shed (a stipulate leaf, such as in roses and beans ), or be shed as the leaf expands, leaving a stipule scar on the twig (an exstipulate leaf). The situation, arrangement, and structure of the stipules is called the "stipulation". Veins (sometimes referred to as nerves) constitute one of the most visible features of leaves. The veins in a leaf represent

2472-405: A specialized cell group known as the stomatal complex. The opening and closing of the stomatal aperture is controlled by the stomatal complex and regulates the exchange of gases and water vapor between the outside air and the interior of the leaf. Stomata therefore play the important role in allowing photosynthesis without letting the leaf dry out. In a typical leaf, the stomata are more numerous over

2575-561: A substitute for tallow in increasing marbling . In the US, flax-based feed for ruminants is often somewhat more expensive than other feeds on a nutrient basis. Sheep feeding on low quality forage are able to eat a large amount of linseed meal, up to 40% in one test, with positive consequences. It has been fed as supplement to water buffaloes in India, and provided a better diet than forage alone, but not as good as when substituted with soy meal. It

2678-483: A variety of patterns (venation) and form cylindrical bundles, usually lying in the median plane of the mesophyll , between the two layers of epidermis . This pattern is often specific to taxa, and of which angiosperms possess two main types, parallel and reticulate (net like). In general, parallel venation is typical of monocots, while reticulate is more typical of eudicots and magnoliids (" dicots "), though there are many exceptions. The vein or veins entering

2781-479: A week. Refrigeration and storage in sealed containers will keep ground flax seed meal for a longer period before it turns rancid. Under conditions similar to those found in commercial bakeries, trained sensory panelists could not detect differences between bread made with freshly ground flax seed and bread made with flax seed that had been milled four months earlier and stored at room temperature. If packed immediately without exposure to air and light, milled flax seed

2884-418: Is Normandy with nearly one-third of the world's production. 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

2987-436: Is a Rijksmonument (listed building). The building was refurbished from 1975. The Jannink museum moved onto the ground floor in 1980; other floors were converted into housing. The 1900 build was laid out with 16 self-acting mules and 48 Asa Lees & Co ring frames giving a total of 30,000 spindles. There were 568 power looms. In 1908 Stott returned and added the water tower and the sprinkler system; outside England it

3090-477: Is a flowering plant , Linum usitatissimum , in the family Linaceae . It is cultivated as a food and fiber crop in regions of the world with temperate climates . In 2022, France produced 75% of the world's supply of flax. Textiles made from flax are known in English as linen , and are traditionally used for bed sheets, underclothes, and table linen. Its oil is known as linseed oil . In addition to referring to

3193-401: Is a protein -rich feed for ruminants , rabbits , and fish. It is also often used as feed for swine and poultry , and has also been used in horse concentrate and dog food . The high omega-3 fatty acid ( ALA ) content of linseed meal "softens" milk, eggs, and meat, which means it causes a higher unsaturated fat content and thus lowers its storage time. The high omega-3 content also has

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3296-542: Is added to cattle feed as a protein supplement . It can only be added at low percentages due to the high fat content, which is unhealthy for ruminants. Compared to oilseed meal from crucifers it measures as having lower nutrient values, however, good results are obtained in cattle, perhaps due to the mucilage, which may aid in slowing digestion and thus allowing more time to absorb nutrients. One study found that feeding flax seeds may increase omega-3 content in beef , while another found no differences. It might also act as

3399-416: 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

3502-554: 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 15–25 mm in diameter with five petals, which can be colored white, blue, yellow, and red depending on the species. The fruit is a round, dry capsule 5–9 mm in diameter, containing several glossy brown seeds shaped like apple pips, 4–7 mm long. The earliest evidence of humans using wild flax as

3605-455: Is called a stipe in ferns . The lamina is the expanded, flat component of the leaf which contains the chloroplasts . The sheath is a structure, typically at the base that fully or partially clasps the stem above the node, where the leaf is attached. Leaf sheathes typically occur in Poaceae (grasses) and Apiaceae (umbellifers). Between the sheath and the lamina, there may be a pseudopetiole ,

3708-474: Is considered an inferior protein supplement for swine because of its fibre, the vitamin antagonist, the high omega-3 content and its low lysine content, and can only be used in small amounts in the feed. Although it may increase the omega-3 content in eggs and meat, it is also an inferior and potentially toxic feed for poultry, although it can be used in small amounts. The meal is an adequate and traditional source of protein for rabbits at 8–10%. Its use in fish feeds

3811-477: Is easily over-retted, damaging the fiber. This form of retting also produces quite an odor. Stream retting is similar to pool retting, but the flax is submerged in bundles in a stream or river. This generally takes two or three weeks longer than pond retting, but the end product is less likely to be dirty, does not smell as bad, and because the water is cooler, is less likely to be over-retted. Both pond and stream retting were traditionally used less because they pollute

3914-550: 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 use of flax fibers dates back tens of millennia; 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

4017-561: Is gripped by rubber belts roughly 20–25 cm (8–10 inches) above ground, to avoid getting grasses and weeds in the flax. The rubber belts then pull the whole plant out of the ground with the roots so the whole length of the plant fiber can be used. The plants then pass over the machine and is placed on the field crosswise to the harvester's direction of travel. The plants are left in the field for field retting . The mature plant can also be cut with mowing equipment, similar to hay harvesting, and raked into windrows. When dried sufficiently,

4120-512: Is limited. Raw, immature linseeds contain an amount of cyanogenic compounds and can be dangerous for monogastric animals, like horses and rabbits. Boiling removes the danger. This is not an issue in meal cake due to the processing temperature during oil extraction. Flax straw left over from the harvesting of oilseed is not very nutritious; it is tough and indigestible, and is not recommended to use as ruminant fodder, although it may be used as bedding or baled as windbreaks . Flax fiber

4223-433: Is nontoxic when consumed in typical amounts. Typical concentrations (for example, 0.48% in a sample of defatted dehusked flax seed 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

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4326-428: Is produced when retting, and it would corrode the metal. If the water temperature is kept at 27 °C (80 °F), the retting process under these conditions takes 4 or 5 days. If the water is any colder, it takes longer. Scum collects at the top, and an odor is given off the same as in pond retting. 'Enzymatic' retting of flax has been researched as a technique to engineer fibers with specific properties. Dressing

4429-421: Is stable against excessive oxidation when stored for nine months at room temperature, and under warehouse conditions, for 20 months at ambient temperatures. Three phenolic glucosides — secoisolariciresinol diglucoside , p-coumaric acid glucoside, and ferulic acid glucoside—are present in commercial breads containing flax seed. After crushing the seeds to extract linseed oil, the resultant linseed meal

4532-406: Is the more complex pattern, branching veins appear to be plesiomorphic and in some form were present in ancient seed plants as long as 250 million years ago. A pseudo-reticulate venation that is actually a highly modified penniparallel one is an autapomorphy of some Melanthiaceae , which are monocots; e.g., Paris quadrifolia (True-lover's Knot). In leaves with reticulate venation, veins form

4635-720: The Mediterranean and the Romans used it for their sails . As the Roman Empire declined, so did flax production. But with laws designed to publicize the hygiene of linen textiles and the health of linseed oil, Charlemagne revived the crop in the eighth century CE . Eventually, Flanders became the major center of the European linen industry in the Middle Ages . In North America, colonists introduced flax, and it flourished there, but by

4738-494: The diet of many animals . Correspondingly, leaves represent heavy investment on the part of the plants bearing them, and their retention or disposition are the subject of elaborate strategies for dealing with pest pressures, seasonal conditions, and protective measures such as the growth of thorns and the production of phytoliths , lignins , tannins and poisons . Deciduous plants in frigid or cold temperate regions typically shed their leaves in autumn, whereas in areas with

4841-424: The gymnosperms and angiosperms . Euphylls are also referred to as macrophylls or megaphylls (large leaves). A structurally complete leaf of an angiosperm consists of a petiole (leaf stalk), a lamina (leaf blade), stipules (small structures located to either side of the base of the petiole) and a sheath. Not every species produces leaves with all of these structural components. The proximal stalk or petiole

4944-551: The phyllids of mosses and liverworts . Leaves are the most important organs of most vascular plants. Green plants are autotrophic , meaning that they do not obtain food from other living things but instead create their own food by photosynthesis . They capture the energy in sunlight and use it to make simple sugars , such as glucose and sucrose , from carbon dioxide and water. The sugars are then stored as starch , further processed by chemical synthesis into more complex organic molecules such as proteins or cellulose ,

5047-399: The plant shoots and roots . Vascular plants transport sucrose in a special tissue called the phloem . The phloem and xylem are parallel to each other, but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch (ramify) to form veins which supply as much of the leaf as possible, ensuring that cells carrying out photosynthesis are close to

5150-453: The shoot system. In most leaves, the primary photosynthetic tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus , palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves are flattened and have distinct upper ( adaxial ) and lower ( abaxial ) surfaces that differ in color, hairiness,

5253-456: The spinning machines needed to spin cotton. The building was modelled on similar double-mills in Lancashire. A central tower housed the engine and the water tank for the sprinklers; to either side were the three-storey mills with the large uninterrupted floors needed for mule spinning. The height of the chimney was determined by up-draught needed by the boilers. The factory operated until 1967. It

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5356-487: The straw from the fiber. Heckling is pulling the fiber through various sizes of heckling combs or heckles. A heckle is a bed of "nails"—sharp, long-tapered, tempered, polished steel pins driven into wooden blocks at regular spacing. In September 2009, Canadian flax exports reportedly had been contaminated by a deregistered genetically modified cultivar called 'Triffid' that had food and feed safety approval in Canada and

5459-684: The 19th century, when cotton overtook flax as the most common plant 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 . Linseed meal, the by-product of producing linseed oil from flax seeds, is used as livestock fodder . Flax seeds occur in brown and yellow (golden) varieties. Most types of these basic varieties have similar nutritional characteristics and equal numbers of short-chain omega-3 fatty acids . Yellow flax seeds, called solin ( trade name " Linola "), have

5562-427: The 2014 crop. Laboratories are certified to test for the presence of Triffid at a level of one seed in 10,000. Leaf A leaf ( pl. : leaves ) is a principal appendage of the stem of a vascular plant , usually borne laterally above ground and specialized for photosynthesis . Leaves are collectively called foliage , as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form

5665-597: The Roombeek neighbourhood, next to the stream in 1900. The fireproof mill was designed and built by Sidney Stott . There were 70 fireproof textile mills constructed in Twente between 1880 and 1914. Stott, the Oldham architect, not to be confused with his cousins Stott and Sons , was a millwright who cooperated with most advanced textile machine manufacturers: the mill was handed over complete with power source , line shafting and all

5768-769: The U.S. Canadian growers and the Flax Council of Canada raised concerns about the marketability of this cultivar in Europe where a zero tolerance policy exists regarding unapproved genetically modified organisms . Consequently, Triffid was deregistered in 2010 and never grown commercially in Canada or the U.S. Triffid stores were destroyed, but future exports and further tests at the University of Saskatchewan proved that Triffid persisted in at least two Canadian flax varieties, possibly affecting future crops. Canadian flax seed cultivars were reconstituted with Triffid-free seed used to plant

5871-679: The amount of light they absorb to avoid or mitigate excessive heat, ultraviolet damage, or desiccation, or to sacrifice light-absorption efficiency in favor of protection from herbivory. For xerophytes the major constraint is not light flux or intensity , but drought. Some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides . Leaves also function to store chemical energy and water (especially in succulents ) and may become specialized organs serving other functions, such as tendrils of peas and other legumes,

5974-583: The basic structural material in plant cell walls, or metabolized by cellular respiration to provide chemical energy to run cellular processes. The leaves draw water from the ground in the transpiration stream through a vascular conducting system known as xylem and obtain carbon dioxide from the atmosphere by diffusion through openings called stomata in the outer covering layer of the leaf ( epidermis ), while leaves are orientated to maximize their exposure to sunlight. Once sugar has been synthesized, it needs to be transported to areas of active growth such as

6077-452: The blade attaches directly to the stem. Subpetiolate leaves are nearly petiolate or have an extremely short petiole and may appear to be sessile. In clasping or decurrent leaves, the blade partially surrounds the stem. When the leaf base completely surrounds the stem, the leaves are said to be perfoliate , such as in Eupatorium perfoliatum . In peltate leaves, the petiole attaches to

6180-406: The blade inside the blade margin. In some Acacia species, such as the koa tree ( Acacia koa ), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes . There may or may not be normal pinnate leaves at the tip of the phyllode. A stipule , present on the leaves of many dicotyledons , is an appendage on each side at the base of the petiole, resembling

6283-448: The crop steadily spread, reaching as far as Switzerland and Germany by 5,000 years ago. In China and India, domesticated flax was cultivated at least 5,000 years ago. Flax was cultivated extensively in ancient Egypt , where the temple walls had paintings of flowering flax, and mummies were embalmed using linen. Egyptian priests wore only linen, as flax was considered a symbol of purity. Phoenicians traded Egyptian linen throughout

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6386-595: The early Devonian lycopsid Baragwanathia , first evolved as enations, extensions of the stem. True leaves or euphylls of larger size and with more complex venation did not become widespread in other groups until the Devonian period , by which time the carbon dioxide concentration in the atmosphere had dropped significantly. This occurred independently in several separate lineages of vascular plants, in progymnosperms like Archaeopteris , in Sphenopsida , ferns and later in

6489-412: The early 20th century, cheap cotton and rising farm wages had caused production of flax to become concentrated in northern Russia, which came to provide 90% of the world's output. Since then, flax has lost its importance as a commercial crop , due to the easy availability of more durable fibres. Flax is grown for its seeds, which can be ground into a meal or turned into linseed oil , a product used as

6592-553: The equivalents of the petioles and stipules of leaves. Because each leaflet can appear to be a simple leaf, it is important to recognize where the petiole occurs to identify a compound leaf. Compound leaves are a characteristic of some families of higher plants, such as the Fabaceae . The middle vein of a compound leaf or a frond , when it is present, is called a rachis . Leaves which have a petiole (leaf stalk) are said to be petiolate . Sessile (epetiolate) leaves have no petiole and

6695-657: The external world. The cuticle is in some cases thinner on the lower epidermis than on the upper epidermis, and is generally thicker on leaves from dry climates as compared with those from wet climates. The epidermis serves several functions: protection against water loss by way of transpiration , regulation of gas exchange and secretion of metabolic compounds. Most leaves show dorsoventral anatomy: The upper (adaxial) and lower (abaxial) surfaces have somewhat different construction and may serve different functions. The epidermis tissue includes several differentiated cell types; epidermal cells, epidermal hair cells ( trichomes ), cells in

6798-401: The fiber. The stems are then pulled through "hackles", which act like combs to remove the straw and some shorter fibers out of the long fiber. Several methods are used for retting flax. It can be retted in a pond, stream, field, or tank. When the retting is complete, the bundles of flax feel soft and slimy, and quite a few fibers are standing out from the stalks. When wrapped around a finger,

6901-407: The field in the spring. Two ways are used to harvest flax fiber, one involving mechanized equipment (combines), and a second method, more manual and targeting maximum fiber length. Flax for fiber production is usually harvested by a specialized flax harvester. Usually built on the same machine base as a combine, but instead of the cutting head it has a flax puller. The flax plant is turned over and

7004-402: The flax is the process of removing the straw from the fibers. Dressing consists of three steps: breaking, scutching, and heckling. The breaking breaks up the straw. Some of the straw is scraped from the fibers in the scutching process, and finally, the fiber is pulled through heckles to remove the last bits of straw. Breaking breaks up the straw into short segments. Scutching removes some of

7107-399: 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

7210-406: The fraction is 5/13. These arrangements are periodic. The denominator of the rotation fraction indicates the number of leaves in one period, while the numerator indicates the number of complete turns or gyres made in one period. For example: Most divergence angles are related to the sequence of Fibonacci numbers F n . This sequence begins 1, 1, 2, 3, 5, 8, 13; each term is the sum of

7313-866: The ground, they are referred to as prostrate . Perennial plants whose leaves are shed annually are said to have deciduous leaves, while leaves that remain through winter are evergreens . Leaves attached to stems by stalks (known as petioles ) are called petiolate, and if attached directly to the stem with no petiole they are called sessile. Dicot leaves have blades with pinnate venation (where major veins diverge from one large mid-vein and have smaller connecting networks between them). Less commonly, dicot leaf blades may have palmate venation (several large veins diverging from petiole to leaf edges). Finally, some exhibit parallel venation. Monocot leaves in temperate climates usually have narrow blades, and usually parallel venation converging at leaf tips or edges. Some also have pinnate venation. The arrangement of leaves on

7416-410: The inner woody part springs away from the fibers. Pond retting is the fastest. It consists of placing the flax in a pool of water which will not evaporate. It generally takes place in a shallow pool which will warm up dramatically in the sun; the process may take from a few days to a few weeks. Pond-retted flax is traditionally considered of lower quality, possibly because the product can become dirty, and

7519-443: The leaf from the petiole are called primary or first-order veins. The veins branching from these are secondary or second-order veins. These primary and secondary veins are considered major veins or lower order veins, though some authors include third order. Each subsequent branching is sequentially numbered, and these are the higher order veins, each branching being associated with a narrower vein diameter. In parallel veined leaves,

7622-523: The leaf veins form, and these have functional implications. Of these, angiosperms have the greatest diversity. Within these the major veins function as the support and distribution network for leaves and are correlated with leaf shape. For instance, the parallel venation found in most monocots correlates with their elongated leaf shape and wide leaf base, while reticulate venation is seen in simple entire leaves, while digitate leaves typically have venation in which three or more primary veins diverge radially from

7725-551: The leaves of vascular plants . In most cases, they lack vascular tissue, are only a single cell thick, and have no cuticle , stomata, or internal system of intercellular spaces. (The phyllids of the moss family Polytrichaceae are notable exceptions.) The phyllids of bryophytes are only present on the gametophytes , while in contrast the leaves of vascular plants are only present on the sporophytes . These can further develop into either vegetative or reproductive structures. Simple, vascularized leaves ( microphylls ), such as those of

7828-552: The number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax and other features. Leaves are mostly green in color due to the presence of a compound called chlorophyll which is essential for photosynthesis as it absorbs light energy from the sun . A leaf with lighter-colored or white patches or edges is called a variegated leaf . Leaves can have many different shapes, sizes, textures and colors. The broad, flat leaves with complex venation of flowering plants are known as megaphylls and

7931-404: The photosynthetic organelles , the chloroplasts , to light and to increase the absorption of carbon dioxide while at the same time controlling water loss. Their surfaces are waterproofed by the plant cuticle and gas exchange between the mesophyll cells and the atmosphere is controlled by minute (length and width measured in tens of μm) openings called stomata which open or close to regulate

8034-412: The plant and provides the route for transfer of water and sugars to and from the leaf. The lamina is typically the location of the majority of photosynthesis. The upper ( adaxial ) angle between a leaf and a stem is known as the axil of the leaf. It is often the location of a bud . Structures located there are called "axillary". External leaf characteristics, such as shape, margin, hairs, the petiole, and

8137-665: The plant, 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. The plants called "flax" in New Zealand are, by contrast, members of the genus Phormium . 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

8240-434: The presence of stipules and glands, are frequently important for identifying plants to family, genus or species levels, and botanists have developed a rich terminology for describing leaf characteristics. Leaves almost always have determinate growth. They grow to a specific pattern and shape and then stop. Other plant parts like stems or roots have non-determinate growth, and will usually continue to grow as long as they have

8343-410: The previous two. Rotation fractions are often quotients F n / F n + 2 of a Fibonacci number by the number two terms later in the sequence. This is the case for the fractions 1/2, 1/3, 2/5, 3/8, and 5/13. The ratio between successive Fibonacci numbers tends to the golden ratio φ = (1 + √5)/2 . When a circle is divided into two arcs whose lengths are in the ratio 1:φ , the angle formed by

8446-465: The primary organs responsible for transpiration and guttation (beads of fluid forming at leaf margins). Leaves can also store food and water , and are modified accordingly to meet these functions, for example in the leaves of succulent plants and in bulb scales. The concentration of photosynthetic structures in leaves requires that they be richer in protein , minerals , and sugars than, say, woody stem tissues. Accordingly, leaves are prominent in

8549-429: The primary veins run parallel and equidistant to each other for most of the length of the leaf and then converge or fuse (anastomose) towards the apex. Usually, many smaller minor veins interconnect these primary veins, but may terminate with very fine vein endings in the mesophyll. Minor veins are more typical of angiosperms, which may have as many as four higher orders. In contrast, leaves with reticulate venation have

8652-416: The products of photosynthesis (photosynthate) from the cells where it takes place, while major veins are responsible for its transport outside of the leaf. At the same time water is being transported in the opposite direction. The number of vein endings is very variable, as is whether second order veins end at the margin, or link back to other veins. There are many elaborate variations on the patterns that

8755-429: The protective spines of cacti and the insect traps in carnivorous plants such as Nepenthes and Sarracenia . Leaves are the fundamental structural units from which cones are constructed in gymnosperms (each cone scale is a modified megaphyll leaf known as a sporophyll) and from which flowers are constructed in flowering plants . The internal organization of most kinds of leaves has evolved to maximize exposure of

8858-714: The rate exchange of carbon dioxide (CO 2 ), oxygen (O 2 ) and water vapor into and out of the internal intercellular space system. Stomatal opening is controlled by the turgor pressure in a pair of guard cells that surround the stomatal aperture. In any square centimeter of a plant leaf, there may be from 1,000 to 100,000 stomata. The shape and structure of leaves vary considerably from species to species of plant, depending largely on their adaptation to climate and available light, but also to other factors such as grazing animals (such as deer), available nutrients, and ecological competition from other plants. Considerable changes in leaf type occur within species, too, for example as

8961-531: The resources to do so. The type of leaf is usually characteristic of a species (monomorphic), although some species produce more than one type of leaf (dimorphic or polymorphic ). The longest leaves are those of the Raffia palm , R. regalis which may be up to 25 m (82 ft) long and 3 m (9.8 ft) wide. The terminology associated with the description of leaf morphology is presented, in illustrated form, at Wikibooks . Where leaves are basal, and lie on

9064-446: The secondary veins, known as tertiary or third order (or higher order) veins, forming a dense reticulate pattern. The areas or islands of mesophyll lying between the higher order veins, are called areoles . Some of the smallest veins (veinlets) may have their endings in the areoles, a process known as areolation. These minor veins act as the sites of exchange between the mesophyll and the plant's vascular system. Thus, minor veins collect

9167-455: The sequence 180°, 90°, 180°, 270°. Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade being separated along a main or secondary vein. The leaflets may have petiolules and stipels,

9270-454: The smaller arc is the golden angle , which is 1/φ × 360° ≈ 137.5° . Because of this, many divergence angles are approximately 137.5° . In plants where a pair of opposite leaves grows from each node, the leaves form a double helix. If the nodes do not rotate (a rotation fraction of zero and a divergence angle of 0°), the two helices become a pair of parallel lines, creating a distichous arrangement as in maple or olive trees. More common in

9373-953: The species that bear them, the majority, as broad-leaved or megaphyllous plants, which also include acrogymnosperms and ferns . In the lycopods , with different evolutionary origins, the leaves are simple (with only a single vein) and are known as microphylls . Some leaves, such as bulb scales, are not above ground. In many aquatic species, the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines . Furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes , and flattened leaf stems called phyllodes which differ from leaves both in their structure and origin. Some structures of non-vascular plants look and function much like leaves. Examples include

9476-399: The stalk. The first step in this process is retting , which is the process of rotting away the inner stalk, leaving the outer parts intact. At this point, straw, or coarse outer stem ( cortex and epidermis ), is still remaining. To remove this, the flax is "broken", the straw is broken up into small, short bits, while the actual fiber is left unharmed. Scutching scrapes the outer straw from

9579-421: The stem is known as phyllotaxis . A large variety of phyllotactic patterns occur in nature: In the simplest mathematical models of phyllotaxis , the apex of the stem is represented as a circle. Each new node is formed at the apex, and it is rotated by a constant angle from the previous node. This angle is called the divergence angle . The number of leaves that grow from a node depends on the plant species. When

9682-547: The stomatal complex; guard cells and subsidiary cells. The epidermal cells are the most numerous, largest, and least specialized and form the majority of the epidermis. They are typically more elongated in the leaves of monocots than in those of dicots . Chloroplasts are generally absent in epidermal cells, the exception being the guard cells of the stomata . The stomatal pores perforate the epidermis and are surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts, forming

9785-401: The straw (stem) from the fiber, and one for further separating the broken straw and matter from the fiber. The second part of the process brings the flax into a state for the very finest purposes, such as lace , cambric , damask , and very fine linen . This second part is performed by a refining machine. Before the flax fibers can be spun into linen, they must be separated from the rest of

9888-511: The surrounding air , promoting cooling. Functionally, in addition to carrying out photosynthesis, the leaf is the principal site of transpiration , providing the energy required to draw the transpiration stream up from the roots, and guttation . Many conifers have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and frost. These are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. Some leaf forms are adapted to modulate

9991-632: The transportation system. Typically leaves are broad, flat and thin (dorsiventrally flattened), thereby maximising the surface area directly exposed to light and enabling the light to penetrate the tissues and reach the chloroplasts , thus promoting photosynthesis. They are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance, plants adapted to windy conditions may have pendent leaves, such as in many willows and eucalypts . The flat, or laminar, shape also maximizes thermal contact with

10094-400: The usable flax fibers from other components requires pulling the stems through a hackle and/or beating the plants to break them. Flax processing is divided into two parts: the first part is generally done by the farmer, to bring the flax fiber into a fit state for general or common purposes. This can be performed by three machines: one for threshing out the seed, one for breaking and separating

10197-512: The use of flax as an industrial fiber. Flax seeds are 7% water, 18% protein , 29% carbohydrates , and 42% fat (table). In 100 grams (3.5 oz) as a reference amount, flax seeds provide 534 kilocalories and contain high levels (20% or more of the Daily Value , DV) of protein, dietary fiber , several B vitamins , and dietary minerals . Flax seeds are especially rich in thiamine , magnesium , and phosphorus (DVs above 90%) (table). As

10300-462: The vascular structure of the organ, extending into the leaf via the petiole and providing transportation of water and nutrients between leaf and stem, and play a crucial role in the maintenance of leaf water status and photosynthetic capacity. They also play a role in the mechanical support of the leaf. Within the lamina of the leaf, while some vascular plants possess only a single vein, in most this vasculature generally divides (ramifies) according to

10403-458: The waters used for the process. In field retting, the flax is laid out in a large field, and dew is allowed to collect on it. This process normally takes a month or more, but is generally considered to provide the highest quality flax fibers, and it produces the least pollution. Retting can also be done in a plastic trash can or any type of water-tight container of wood, concrete, earthenware, or plastic. Metal containers will not work, as an acid

10506-696: Was discovered in Euonymeia , Greece. The best grades are used for 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 , laboratory paper ( blotting and filter ), rolling paper for cigarettes , and tea bags . Flax mills for spinning flaxen yarn were invented by John Kendrew and Thomas Porthouse of Darlington , England , in 1787. New methods of processing flax have led to renewed interest in

10609-434: Was tradition to build the name of the mill into the chimney rather than the water tower. The Enschede fireworks disaster of 2000 devastated Roombeek. In its aftermath, three collections were combined in Roombeek. Notes Footnotes Bibliography 52°13′56″N 6°53′28″E  /  52.2323°N 6.8910°E  / 52.2323; 6.8910 Flax Flax , also known as common flax or linseed ,

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