Metasequoia glyptostroboides, the dawn redwood, is a fast-growing, endangered deciduous conifer, the sole living species of the genus Metasequoia, one of three species in the subfamily Sequoioideae. It now survives only in wet lower slopes and montane river and stream valleys in the border region of Hubei and Hunan provinces and Chongqing municipality in south-central China, notably in Lichuan county in Hubei. Although shortest of the redwoods, it can grow to at least 165 ft in height. In 1941, the genus Metasequoia was reported by palaeobotanist Shigeru Miki as a distributed extinct genus based on fossils, before attracting considerable attention a few years when small populations were found alive in central China, it is a well-known example of a living fossil species. The tree faces considerable risks of extinction in its wild range due to deforestation, so has been planted extensively in arboreta worldwide, where it has proved a popular and fast-growing ornamental plant. Though once common across the northern hemisphere, the dawn redwood was considered extinct.
The genus Metasequoia was first described in 1941 as a fossil of the Mesozoic Era, none of the fossils discovered was less than 150 million years old. Dr. Shigeru Miki, a paleobotanist from Kyoto University, identified a divergent leaf form while studying fossil samples of the family Cupressaceae and realized he was looking at a new genus, which he named Metasequoia, meaning "like a sequoia". In the same year a forester named T. Kan came across an enormous living specimen while performing a survey in Sichuan and Hubei provinces. Though unaware of Miki's new genus, he recognized the unique traits of the tree, it formed part of a local shrine, where villagers called it Shui-shan 水杉 or "water fir". In 1943, Zhan Wang, a Chinese forestry official, collected samples from an unidentified tree in the village of Maodaoqi or Modaoxi in Lichuan County, Hubei province—now believed to be the same tree Kan discovered; the samples were determined to belong to a tree yet unknown to science, but World War II postponed further study.
Professors Wan Chun Cheng and Hu Xiansu made the pivotal connection between Miki's genus and the living samples in 1946, provided the specific epithet "glyptostroboides", after its resemblance to the Chinese swamp cypress. In 1948 the Arnold Arboretum of Harvard University funded an expedition to collect seeds from Kan's original tree and, soon after, distributed seeds and seedlings to various universities and arboreta worldwide for growth trials. Of these, two were distributed to the H. H. Hunnewell estate in Wellesley, where they were still alive as of 2016; the seeds distributed to Hillier Gardens near Winchester, UK, have thrived and are now the emblem of the gardens. Seedlings have been for sale since 1949. Together with Sequoia sempervirens and Sequoiadendron giganteum of California, M. glyptostroboides is classified in the subfamily Sequoioideae of the family Cupressaceae. Although it is the only living species in its genus, three fossil species are known as well; the other Sequoioideae and several other genera have been transferred from the Taxodiaceae to the Cupressaceae based on DNA analysis.
While the bark and foliage are similar to another related genus of redwoods, Sequoia, M. glyptostroboides differs from the coast redwood in that it is deciduous, like Taxodium distichum. Similar to T. distichum, older trees may form wide buttresses on the lower trunk. M. glyptostroboides is a fast-growing tree, exceeding 35 m in height and 1 m in trunk diameter by the age of 50, in cultivation. The trunk forms a distinctive "armpit" under each branch; the bark tends to exfoliate in ribbon-like strips. The largest dawn redwood recorded was an isolated specimen in China about 50 meters tall and 2.2 meters wide. This tree was killed by a lightning strike in 1951. Several dawn redwoods of this height still live in the eastern part of Shuishaba Valley, AKA Metasequoia Valley, where the tree was discovered; the tree's true potential size is much larger, as logs up to 8 meters wide at the base have been discovered in rice paddies. The thickest and tallest dawn redwoods listed by Momumental Trees are both in the Longwood Gardens of Kennett Square in Pennsylvania, United States.
The widest has a girth at breast height of 5.79 m, is 30.18 m tall. The tallest is 41.15 m tall, has a girth at breast height of 3.35 m. Both trees were planted in 1948 and measured in 2018; the leaves are opposite, 1–3 cm long, bright fresh green, turning a foxy reddish brown in fall. The pollen cones are 5–6 mm long, produced on long spikes in early spring; the cones are globose to ovoid, 1.5–2.5 cm in diameter with 16-28 scales arranged in opposite pairs in four rows, each pair at right angles to the adjacent pair. Studies carried out between 2007-9 counted 5371 trees in Lichuan, with much smaller groups in Shizhu and Longshan, Hunan; the floodplain of Metasequoia Valley in Hubei had been turned to rice paddies by the time of the tree's discovery, but was once a more extensive dawn redwood forest. Such a forest would have been similar to bald cypress forests in the United States, with many similar species growing in association. Nearly 3,000 trunks were found in the floor of the valley, ranging from 2 meters (6.5
A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot. Leaves are collectively referred to as foliage, as in "autumn foliage". A leaf is a thin, dorsiventrally flattened organ borne above ground and specialized for photosynthesis. In most leaves, the primary photosynthetic tissue, the palisade mesophyll, 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 have distinct upper surface and lower surface that differ in colour, the number of stomata, the amount and structure of epicuticular wax and other features. Leaves can have many different shapes and textures; the broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In the clubmosses, with different evolutionary origins, the leaves are simple 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 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 homologous with them. Examples include flattened plant stems called phylloclades and cladodes, flattened leaf stems called phyllodes which differ from leaves both in their structure and origin; some structures of non-vascular plants function much like leaves. Examples include the phyllids of 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 stored as starch, further processed by chemical synthesis into more complex organic molecules such as proteins or cellulose, the basic structural material in plant cell walls, or metabolised 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, while leaves are orientated to maximise their exposure to sunlight. Once sugar has been synthesized, it needs to be transported to areas of active growth such as 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 in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much of the leaf as possible, ensuring that cells carrying out photosynthesis are close to the transportation system. Leaves are broad and thin, 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 eucalyptss; the flat, or laminar, shape maximises thermal contact with 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, guttation. Many gymnosperms 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 the amount of light they absorb to avoid or mitigate excessive heat, ultraviolet damage, or desiccation, or to sacrifice light-absorption efficiency in favour of protection from herbivory.
For xerophytes the major constraint 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 function to store chemical energy and water and may become specialised organs serving other functions, such as tendrils of peas and other legumes, 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 and from which flowers are constructed in flowering plants; the internal organisation of most kinds of leaves has evolved to maximise exposure of 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 openings called stomata which open or close to regulate the rate exchange of carbon dioxide and water vapour into
The plastid is a membrane-bound organelle found in the cells of plants and some other eukaryotic organisms. Plastids were discovered and named by Ernst Haeckel, but A. F. W. Schimper was the first to provide a clear definition. Plastids are the site of manufacture and storage of important chemical compounds used by the cells of autotrophic eukaryotes, they contain pigments used in photosynthesis, the types of pigments in a plastid determine the cell's color. They have a common evolutionary origin and possess a double-stranded DNA molecule, circular, like that of prokaryotic cells. Plastids that contain chlorophyll are called chloroplasts. Plastids can store products like starch and can synthesize fatty acids and terpenes, which can be used for producing energy and as raw material for the synthesis of other molecules. For example, the components of the plant cuticle and its epicuticular wax are synthesized by the epidermal cells from palmitic acid, synthesized in the chloroplasts of the mesophyll tissue.
All plastids are derived from proplastids, which are present in the meristematic regions of the plant. Proplastids and young chloroplasts divide by binary fission, but more mature chloroplasts have this capacity. In plants, plastids may differentiate into several forms, depending upon which function they play in the cell. Undifferentiated plastids may develop into any of the following variants: Chloroplasts: green plastids for photosynthesis; each plastid creates multiple copies of a circular 75–250 kilobase plastome. The number of genome copies per plastid is variable, ranging from more than 1000 in dividing cells, which, in general, contain few plastids, to 100 or fewer in mature cells, where plastid divisions have given rise to a large number of plastids; the plastome contains about 100 genes encoding ribosomal and transfer ribonucleic acids as well as proteins involved in photosynthesis and plastid gene transcription and translation. However, these proteins only represent a small fraction of the total protein set-up necessary to build and maintain the structure and function of a particular type of plastid.
Plant nuclear genes encode the vast majority of plastid proteins, the expression of plastid genes and nuclear genes is co-regulated to coordinate proper development of plastids in relation to cell differentiation. Plastid DNA exists as large protein-DNA complexes associated with the inner envelope membrane and called'plastid nucleoids'; each nucleoid particle may contain more than 10 copies of the plastid DNA. The proplastid contains a single nucleoid located in the centre of the plastid; the developing plastid has many nucleoids, localized at the periphery of the plastid, bound to the inner envelope membrane. During the development of proplastids to chloroplasts, when plastids convert from one type to another, nucleoids change in morphology and location within the organelle; the remodelling of nucleoids is believed to occur by modifications to the composition and abundance of nucleoid proteins. Many plastids those responsible for photosynthesis, possess numerous internal membrane layers. In plant cells, long thin protuberances called stromules sometimes form and extend from the main plastid body into the cytosol and interconnect several plastids.
Proteins, smaller molecules, can move within stromules. Most cultured cells that are large compared to other plant cells have long and abundant stromules that extend to the cell periphery. In 2014, evidence of possible plastid genome loss was found in Rafflesia lagascae, a non-photosynthetic parasitic flowering plant, in Polytomella, a genus of non-photosynthetic green algae. Extensive searches for plastid genes in both Rafflesia and Polytomella yielded no results, however the conclusion that their plastomes are missing is still controversial; some scientists argue that plastid genome loss is unlikely since non-photosynthetic plastids contain genes necessary to complete various biosynthetic pathways, such as heme biosynthesis. In algae, the term leucoplast is used for all unpigmented plastids, their function differs from the leucoplasts of plants. Etioplasts and chromoplasts are plant-specific and do not occur in algae. Plastids in algae and hornworts may differ from plant plastids in that they contain pyrenoids.
Glaucophyte algae contain muroplasts, which are similar to chloroplasts except that they have a peptidoglycan cell wall, similar to that of prokaryotes. Red algae contain rhodoplasts, which are red chloroplasts that allow them to photosynthesise to a depth of up to 268 m; the chloroplasts of plants differ from the rhodoplasts of red algae in their ability to synthesize starch, stored in the form of granules within the plastids. In red algae, floridean starch is stored outside the plastids in the cytosol. Most plants inherit the plastids from only one parent. In general, angiosperms inherit plastids from the female gamete, whereas
History of plant systematics
The history of plant systematics—the biological classification of plants—stretches from the work of ancient Greek to modern evolutionary biologists. As a field of science, plant systematics came into being only early plant lore being treated as part of the study of medicine. Classification and description was driven by natural history and natural theology; until the advent of the theory of evolution, nearly all classification was based on the scala naturae. The professionalization of botany in the 18th and 19th century marked a shift toward more holistic classification methods based on evolutionary relationships; the Sushrut first classify plant in 4 categories on basis of flowering pattern structure and life span. Vanspataya Vruksha Virudh Aushodh तासां स्थावराश्चतुर्विधाः- वनस्पतयो, वृक्षा, वीरुध, ओषधय इति | तासु, अपुष्पाः फलवन्तो वनस्पतयः, पुष्पफलवन्तो वृक्षाः, प्रतानवत्यः स्तम्बिन्यश्च वीरुधः, फलपाकनिष्ठा ओषधय इति ||Sushrut Sutra 1/21|| <<https://en.wikipedia.org/wiki/Sushruta>> The peripatetic philosopher Theophrastus, as a student of Aristotle in Ancient Greece, wrote Historia Plantarum, the earliest surviving treatise on plants, where he listed the names of over 500 plant species.
He did not articulate a formal classification scheme, but relied on the common groupings of folk taxonomy combined with growth form: tree shrub. The De Materia Medica of Dioscorides was an important early compendium of plant descriptions, classifying plants chiefly by their medicinal effects. In the 16th century, works by Otto Brunfels, Hieronymus Bock, Leonhart Fuchs helped to revive interest in natural history based on first-hand observation. With the influx of exotic species in the Age of Exploration, the number of known species expanded but most authors were far more interested in the medicinal properties of individual plants than an overarching classification system. Influential Renaissance books include those of Caspar Bauhin and Andrea Cesalpino. Bauhin described over 6000 plants, which he arranged into 12 books and 72 sections based on a wide range of common characteristics. Cesalpino based his system on the structure of the organs of fructification, using the Aristotelian technique of logical division.
In the late 17th century, the most influential classification schemes were those of English botanist and natural theologian John Ray and French botanist Joseph Pitton de Tournefort. Ray, who listed over 18,000 plant species in his works, is credited with establishing the monocot/dicot division and some of his groups — mustards, mints and grasses — stand today. Tournefort used an artificial system based on logical division, adopted in France and elsewhere in Europe up until Linnaeus; the book that had an enormous accelerating effect on the science of plant systematics was Species Plantarum by Linnaeus. It presented a complete list of the plant species known to Europe, ordered for the purpose of easy identification using the number and arrangement of the male and female sexual organs of the plants. Of the groups in this book, the highest rank that continues to be used today is the genus; the consistent use of binomial nomenclature along with a complete listing of all plants provided a huge stimulus for the field.
Although meticulous, the classification of Linnaeus served as an identification manual. It assumed that plant species were given by God and that what remained for humans was to recognise them and use them. Linnaeus was quite aware that the arrangement of species in the Species Plantarum was not a natural system, i.e. did not express relationships. However he did present some ideas of plant relationships elsewhere. Significant contributions to plant classification came from de Jussieu in 1789 and the early nineteenth century saw the start of work by de Candolle, culminating in the Prodromus. A major influence on plant systematics was the theory of evolution, resulting in the aim to group plants by their phylogenetic relationships. To this was added the interest in plant anatomy, aided by the use of the light microscope and the rise of chemistry, allowing the analysis of secondary metabolites; the strict use of epithets in botany, although regulated by international codes, is considered unpractical and outdated.
The notion of species, the fundamental classification unit, is up to subjective intuition and thus can not be well defined. As a result, estimate of the total number of existing "species" becomes a matter of preference. While scientists have agreed for some time that a functional and objective classification system must reflect actual evolutionary processes and genetic relationships, the technological means for creating such a system did not exist until recently. In the 1990s DNA technology saw immense progress, resulting in unprecedented accumulation of DNA sequence data from various genes present in compartments of plant cells. In 1998 a ground-breaking classification of the angiosperms consolidated molecular phylogenetics as the best available method. For the first time relatedness could be measured in real terms, namely similarity of the m
Vascular plants known as tracheophytes, form a large group of plants that are defined as those land plants that have lignified tissues for conducting water and minerals throughout the plant. They have a specialized non-lignified tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, ferns and angiosperms. Scientific names for the group include Tracheophyta and Equisetopsida sensu lato; the term higher plants should be avoided as a synonym for vascular plants as it is a remnant of the abandoned concept of the great chain of being. Vascular plants are defined by three primary characteristics: Vascular plants have vascular tissues which distribute resources through the plant; this feature allows vascular plants to evolve to a larger size than non-vascular plants, which lack these specialized conducting tissues and are thereby restricted to small sizes. In vascular plants, the principal generation phase is the sporophyte, which produce spores and is diploid. By contrast, the principal generation phase in non-vascular plants is the gametophyte, which produces gametes and is haploid.
They have true roots and stems if one or more of these traits are secondarily lost in some groups. The formal definition of the division Tracheophyta encompasses both these characteristics in the Latin phrase "facies diploida xylem et phloem instructa". One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spores, enabled the development of the ability to release them higher and to broadcast them farther; such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, more branching. A proposed phylogeny of the vascular plants after Kenrick and Crane is as follows, with modification to the gymnosperms from Christenhusz et al. Pteridophyta from Smith et al. and lycophytes and ferns by Christenhusz et al.
This phylogeny is supported by several molecular studies. Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns are not monophyletic. Water and nutrients in the form of inorganic solutes are drawn up from the soil by the roots and transported throughout the plant by the xylem. Organic compounds such as sucrose produced by photosynthesis in leaves are distributed by the phloem sieve tube elements; the xylem consists of vessels in flowering plants and tracheids in other vascular plants, which are dead hard-walled hollow cells arranged to form files of tubes that function in water transport. A tracheid cell wall contains the polymer lignin; the phloem however consists of living cells called sieve-tube members. Between the sieve-tube members are sieve plates, which have pores to allow molecules to pass through. Sieve-tube members lack such organs as nuclei or ribosomes, but cells next to them, the companion cells, function to keep the sieve-tube members alive.
The most abundant compound in all plants, as in all cellular organisms, is water which serves an important structural role and a vital role in plant metabolism. Transpiration is the main process of water movement within plant tissues. Water is transpired from the plant through its stomata to the atmosphere and replaced by soil water taken up by the roots; the movement of water out of the leaf stomata creates a transpiration pull or tension in the water column in the xylem vessels or tracheids. The pull is the result of water surface tension within the cell walls of the mesophyll cells, from the surfaces of which evaporation takes place when the stomata are open. Hydrogen bonds exist between water molecules; the draw of water upwards may be passive and can be assisted by the movement of water into the roots via osmosis. Transpiration requires little energy to be used by the plant. Transpiration assists the plant in absorbing nutrients from the soil as soluble salts. Living root cells passively absorb water in the absence of transpiration pull via osmosis creating root pressure.
It is possible for there to be no evapotranspiration and therefore no pull of water towards the shoots and leaves. This is due to high temperatures, high humidity, darkness or drought. Xylem and phloem tissues are involved in the conduction processes within plants. Sugars are conducted throughout the plant in the phloem and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves by photosynthesis and transported to the growing shoots and roots for use in growth, cellular respiration or storage. Minerals are transported to the shoots to allow cell division and growth. Fern allies Non-vascular plant “Higher plants” or “vascular plants”
In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, the innermost cell layer of the cortex; the concept of the stele was developed in the late 19th century by French botanists P. E. L. van Tieghem and H. Doultion as a model for understanding the relationship between the shoot and root, for discussing the evolution of vascular plant morphology. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy of different steles affect the function of organs; the earliest vascular plants had stems with a central core of vascular tissue. This consisted of a cylindrical strand of xylem, surrounded by a region of phloem.
Around the vascular tissue there might have been an endodermis that regulated the flow of water into and out of the vascular system. Such an arrangement is termed a protostele. There are three basic types of protostele: haplostele – consisting of a cylindrical core of xylem surrounded by a ring of phloem. An endodermis surrounds the stele. A centrarch haplostele is prevalent in members such as Rhynia. Actinostele – a variation of the protostele in which the core is lobed or fluted; this stele is found in many species of club moss. Actinosteles are exarch and consist of several to many patches of protoxylem at the tips of the lobes of the metaxylem. Exarch protosteles are a defining characteristic of the lycophyte lineage. Plectostele – a protostele in which plate-like regions of xylem appear in transverse section surrounded by phloem tissue. In fact, these discrete plates are interconnected in longitudinal section; some modern club mosses have plectosteles in their stems. The plectostele may be derived from the actinostele.
Siphonosteles have a region of ground tissue called the pith internal to xylem. The vascular strand comprises a cylinder surrounding the pith. Siphonosteles have interruptions in the vascular strand where leaves originate. Siphonosteles can be ectophloic or they can be amphiphloic. Among living plants, many ferns and some Asterid flowering plants have an amphiphloic stele. An amphiphloic siphonostele can be called a: solenostele – if the cylinder of vascular tissue contains no more than one leaf gap in any transverse section; this type of stele is found in fern stems today. Dictyostele – if multiple gaps in the vascular cylinder exist in any one transverse section; the numerous leaf gaps and leaf traces give a dictyostele the appearance of many isolated islands of xylem surrounded by phloem. Each of the isolated units of a dictyostele can be called a meristele. Among living plants, this type of stele is found only in the stems of ferns. Most seed plant stems possess a vascular arrangement, interpreted as a derived siphonostele, is called a eustele – in this arrangement, the primary vascular tissue consists of vascular bundles in one or two rings around the pith.
In addition to being found in stems, the eustele appears in the roots of monocot flowering plants. The vascular bundles in a eustele can be bicollateral. There is a variant of the eustele found in monocots like maize and rye; the variation is called an atactostele. However, it is just a variant of the eustele. Vascular tissue Vascular bundle
Celery is a marshland plant in the family Apiaceae, cultivated as a vegetable since antiquity. Celery has a long fibrous stalk tapering into leaves. Depending on location and cultivar, either its stalks, leaves, or hypocotyl are eaten and used in cooking. Celery seed is used as a spice and its extracts have been used in herbal medicine. Celery leaves are pinnate to bipinnate with rhombic leaflets 3–6 cm long and 2–4 cm broad; the flowers are creamy-white, 2–3 mm in diameter, are produced in dense compound umbels. The seeds are broad ovoid to globose, 1.5 -- 2 mm wide. Modern cultivars have been selected for leaf stalks. A celery stalk separates into "strings" which are bundles of angular collenchyma cells exterior to the vascular bundles. Wild celery, Apium graveolens var. graveolens, grows to 1 m tall. It occurs around the globe; the first cultivation is thought to have happened in the Mediterranean region, where the natural habitats were salty and wet, or marshy soils near the coast where celery grew in agropyro-rumicion-plant communities.
North of the alps wild celery is found only in the foothill zone on soils with some salt content. It prefers nutrient rich, muddy soils, it cannot be found in Austria and is rare in Germany. First attested in English in 1664, the word "celery" derives from the French céleri, in turn from Italian seleri, the plural of selero, which comes from Late Latin selinon, the latinisation of the Ancient Greek: σέλινον, translit. Selinon, "celery"; the earliest attested form of the word is the Mycenaean Greek se-ri-no, written in Linear B syllabic script. Celery was described by Carl Linnaeus in Volume One of his Species Plantarum in 1753; the plants are raised from seed, sown either in a hot bed or in the open garden according to the season of the year, after one or two thinnings and transplantings, they are, on attaining a height of 15–20 cm, planted out in deep trenches for convenience of blanching, effected by earthing up to exclude light from the stems. In the past, celery was grown as a vegetable for winter and early spring.
By the 19th century, the season for celery had been extended, to last from the beginning of September to late in April. In North America, commercial production of celery is dominated by the cultivar called'Pascal' celery. Gardeners can grow a range of cultivars, many of which differ from the wild species in having stouter leaf stems, they are ranged under two classes and red. The stalks grow in tight, parallel bunches, are marketed fresh that way, without roots and just a little green leaf remaining; the stalks are eaten raw, or as an ingredient in salads, or as a flavoring in soups and pot roasts. In Europe, another popular variety is celeriac, Apium graveolens var. rapaceum, grown because its hypocotyl forms a large bulb, white on the inside. The bulb can be kept for months in winter and serves as a main ingredient in soup, it can be shredded and used in salads. The leaves are used as seasoning. Leaf celery is a cultivar from East Asia. Leaf celery is most the oldest cultivated form of celery. Leaf celery has characteristically thin skin stalks and a stronger taste and smell compared to other cultivars.
It is sometimes pickled as a side dish. The wild form of celery is known as "smallage", it has a furrowed stalk with wedge-shaped leaves, the whole plant having a coarse, earthy taste, a distinctive smell. The stalks are not eaten, but the leaves may be used in salads, its seeds are those sold as a spice. With cultivation and blanching, the stalks lose their acidic qualities and assume the mild, aromatic taste particular to celery as a salad plant; because wild celery is eaten, yet susceptible to the same diseases as more well-used cultivars, it is removed from fields to help prevent transmission of viruses like celery mosaic virus. Harvesting occurs; the petioles and leaves are harvested. During commercial harvesting, celery is packaged into cartons which contain between 36 and 48 stalks and weigh up to 27 kg. Under optimal conditions, celery can be stored for up to seven weeks between 0 to 2 °C. Inner stalks may continue growing if kept at temperatures above 0 °C. Shelf life can be extended by packaging celery in micro-perforated shrink wrap.
Freshly cut petioles of celery are prone to decay, which can be prevented or reduced through the use of sharp blades during processing, gentle handling, proper sanitation. Celery stalk may be preserved through pickling by first removing the leaves boiling the stalks in water before adding vinegar and vegetable oil. In the past, restaurants used to store celery in a container of water with powdered vegetable preservative, but it was found that the sulfites in the preservative caused allergic reactions in some people. In 1986, the U. S. Food and Drug Administration banned the use of sulfites on fruits and vegetables intended to be eaten ra