A garden is a planned space outdoors, set aside for the display, cultivation, or enjoyment of plants and other forms of nature. The garden can incorporate both man-made materials; the most common form today is known as a residential garden, but the term garden has traditionally been a more general one. Zoos, which display wild animals in simulated natural habitats, were called zoological gardens. Western gardens are universally based on plants, with garden signifying a shortened form of botanical garden; some traditional types of eastern gardens, such as Zen gardens, use plants not at all. Gardens may exhibit structural enhancements, sometimes called follies, including water features such as fountains, waterfalls or creeks, dry creek beds, arbors and more; some gardens are for ornamental purposes only, while some gardens produce food crops, sometimes in separate areas, or sometimes intermixed with the ornamental plants. Food-producing gardens are distinguished from farms by their smaller scale, more labor-intensive methods, their purpose.
Flower gardens combine plants of different heights, colors and fragrances to create interest and delight the senses. Gardening is the activity of maintaining the garden; this work is done by an professional gardener. A gardener might work in a non-garden setting, such as a park, a roadside embankment, or other public space. Landscape architecture is a related professional activity with landscape architects tending to specialise in design for public and corporate clients; the etymology of the word gardening refers to enclosure: it is from Middle English gardin, from Anglo-French gardin, jardin, of Germanic origin. See Grad for more complete etymology; the words yard and Latin hortus, are cognates—all referring to an enclosed space. The term "garden" in British English refers to a small enclosed area of land adjoining a building; this would be referred to as a yard in American English. Garden design is the process of creating plans for the layout and planting of gardens and landscapes. Gardens may be designed by professionals.
Professional garden designers tend to be trained in principles of design and horticulture, have a knowledge and experience of using plants. Some professional garden designers are landscape architects, a more formal level of training that requires an advanced degree and a state license. Elements of garden design include the layout of hard landscape, such as paths, walls, water features, sitting areas and decking, as well as the plants themselves, with consideration for their horticultural requirements, their season-to-season appearance, growth habit, speed of growth, combinations with other plants and landscape features. Consideration is given to the maintenance needs of the garden, including the time or funds available for regular maintenance, which can affect the choices of plants regarding speed of growth, spreading or self-seeding of the plants, whether annual or perennial, bloom-time, many other characteristics. Garden design can be divided into two groups and naturalistic gardens; the most important consideration in any garden design is, how the garden will be used, followed by the desired stylistic genres, the way the garden space will connect to the home or other structures in the surrounding areas.
All of these considerations are subject to the limitations of the budget. Budget limitations can be addressed by a simpler garden style with fewer plants and less costly hardscape materials, seeds rather than sod for lawns, plants that grow quickly. Most gardens consist of a mix of natural and constructed elements, although very'natural' gardens are always an inherently artificial creation. Natural elements present in a garden principally comprise flora, soil, water and light. Constructed elements include paths, decking, drainage systems and buildings, but living constructions such as flower beds and lawns. A garden can have aesthetic and recreational uses: Cooperation with nature Plant cultivation Garden-based learning Observation of nature Bird- and insect-watching Reflection on the changing seasons Relaxation Family dinners on the terrace Children playing in the garden Reading and relaxing in the hammock Maintaining the flowerbeds Pottering in the shed Cottaging in the bushes Basking in warm sunshine Escaping oppressive sunlight and heat Growing useful produce Flowers to cut and bring inside for indoor beauty Fresh herbs and vegetables for cooking Back garden Cactus garden Gardens may feature a particular plant or plant type.
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone; the male cones, which produce pollen, are herbaceous and much less conspicuous at full maturity. The name "cone" derives from the fact; the individual plates of a cone are known as scales. The male cone is structurally similar across all conifers, differing only in small ways from species to species. Extending out from a central axis are microsporophylls. Under each microsporophyll is several microsporangia; the female cone contains ovules. The female cone structure varies more markedly between the different conifer families, is crucial for the identification of many species of conifers; the members of the pine family have cones. These pine cones the woody female cones, are considered the "archetypal" tree cones; the female cone has two types of scale: the bract scales, the seed scales, one subtended by each bract scale, derived from a modified branchlet. On the upper-side base of each seed scale are two ovules that develop into seeds after fertilization by pollen grains.
The bract scales develop first, are conspicuous at the time of pollination. The scales open temporarily to receive gametophytes close during fertilization and maturation, re-open again at maturity to allow the seed to escape. Maturation takes 6–8 months from pollination in most Pinaceae genera, but 12 months in cedars and 18–24 months in most pines; the cones open either by the seed scales flexing back when they dry out, or by the cones disintegrating with the seed scales falling off. The cones are conic, cylindrical or ovoid, small to large, from 2–60 cm long and 1–20 cm broad. After ripening, the opening of non-serotinous pine cones is associated with their moisture content—cones are open when dry and closed when wet; this assures that the small, wind disseminated seeds will be dispersed during dry weather, thus, the distance traveled from the parent tree will be enhanced. A pine cone will go through many cycles of opening and closing during its life span after seed dispersal is complete; this process occurs with older cones while attached to branches and after the older cones have fallen to the forest floor.
The condition of fallen pine cones is a crude indication of the forest floor's moisture content, an important indication of wildfire risk. Closed cones indicate damp conditions; as a result of this, pine cones have been used by people in temperate climates to predict dry and wet weather hanging a harvested pine cone from some string outside to measure the humidity of the air. Members of the Araucariaceae have the bract and seed scales fused, have only one ovule on each scale; the cones are spherical or nearly so, large to large, 5–30 cm diameter, mature in 18 months. In Agathis, the seeds are winged and separate from the seed scale, but in the other two genera, the seed is wingless and fused to the scale; the cones of the Podocarpaceae are similar in function, though not in development, to those of the Taxaceae, being berry-like with the scales modified, evolved to attract birds into dispersing the seeds. In most of the genera, two to ten or more scales are fused together into a swollen, brightly coloured, edible fleshy aril.
Only one or two scales at the apex of the cone are fertile, each bearing a single wingless seed, but in Saxegothaea several scales may be fertile. The fleshy scale complex is 0.5–3 cm long, the seeds 4–10 mm long. In some genera, the scales are minute and not fleshy, but the seed coat develops a fleshy layer instead, the cone having the appearance of one to three small plums on a central stem; the seeds have a hard coat evolved to resist digestion in the bird's stomach. Members of the cypress family differ in that the bract and seed scales are fused, with the bract visible as no more than a small lump or spine on the scale; the botanical term galbulus is sometimes used instead of strobilus for members of this family. The female cones have one to 20 ovules on each scale, they have peltate scales, as opposed to the imbricate cones described above, though some have imbricate scales. The cones are small, 0.3–6 cm or 1⁄8–2 3⁄8 inches long, spherical or nearly so, like those of Nootka cypress, while others, such as western redcedar and California incense-cedar, are narrow.
The scales are arranged either spirally, or in decussate whorls of two or three four. The genera with spiral scale arrangement were treated in a separate family in the past. In most of the genera, the cones are woody and the seeds have two narrow wings, but in three genera, the seeds are wingless, in Juniperus, the cones are fleshy and
Agricultural Research Service
The Agricultural Research Service is the principal in-house research agency of the United States Department of Agriculture. ARS is one of four agencies in USDA's Research and Economics mission area. ARS is charged with extending the nation's scientific knowledge and solving agricultural problems through its four national program areas: nutrition, food safety and quality. ARS research focuses on solving problems affecting Americans every day; the ARS Headquarters is located in the Jamie L. Whitten Building on Independence Avenue in Washington, D. C. and the headquarters staff is located at the George Washington Carver Center in Beltsville, Maryland. For 2018, its budget was $1.2 billion. ARS conducts scientific research for the American public, their main focus is on research to develop solutions to agricultural problems and provide information access and dissemination to: ensure high quality, safe food and other agricultural products, assess the nutritional needs of Americans, sustain a competitive agricultural economy, enhance the natural resource base and the environment, provide economic opportunities to rural citizens and society as a whole.
ARS research complements the work of state colleges and universities, agricultural experiment stations, other federal and state agencies, the private sector. ARS research may focus on regional issues that have national implications, where there is a clear federal role. ARS provides information on its research results to USDA action and regulatory agencies and to several other federal regulatory agencies, including the Food and Drug Administration and the United States Environmental Protection Agency. ARS disseminates much of its research results through scientific journals, technical publications, Agricultural Research magazine, other forums. Information is distributed through ARS's National Agricultural Library. ARS has more than 150 librarians and other information specialists who work at two NAL locations—the Abraham Lincoln Building in Beltsville, Maryland. C. NAL provides reference and information services, document delivery, interlibrary loan and interlibrary borrowing services to a variety of audiences.
ARS supports more than 2,000 scientists and post docs working on 690 research projects within 15 National Programs at more than 90 research locations. The ARS is divided into 5 geographic areas: Midwest Area, Northeast Area, Pacific West Area, Plains Area, Southeast Area. ARS has five major regional research centers: the Western Regional Research Center in Albany, California; the research centers focus on innovation in agricultural practices, pest control and nutrition among other things. Work at these facilities has given life to numerous products and technologies; the ARS offers the Culture Collection, the largest public collection of microorganisms in the world, containing 93,000 strains of bacteria and fungi. The ARS Culture Collection is housed at Northern Regional Research Laboratory ARS' Henry A. Wallace Beltsville Agricultural Research Center in Beltsville, Maryland, is the world's largest agricultural research complex. ARS operates the U. S. Horticultural Research Laboratory in Fort Pierce and the U.
S. National Poultry Research Center in Athens, Georgia. ARS has six major human nutrition research centers that focus on solving a wide spectrum of human nutrition questions by providing authoritative, peer-reviewed, science-based evidence; the centers are located in Arkansas, Texas, North Dakota and California. ARS scientists at these centers study the role of food and dietary components in human health from conception to advanced age. Technology to produce lactose-free milk, ice cream and yogurt was developed by the USDA Agricultural Research Service in 1985; the grape breeding program, which dates back to 1923, developed seedless grapes. The ARS Citrus and Subtropical Products Laboratory in Winter Haven, Florida, is active in work to improve the taste of orange juice concentrate. ARS had a Toxoplasma gondii research program, which experimented on cats infected with the parasite, from 1982 until 2019. Cats were bred for the program and intentionally infected, kittens in the program were euthanized after research was completed.
Cats were fed raw cat and dog meat for the study, called "kitten cannibalism" by the White Coat Waste Project. A bipartisan bill to eliminate the practice was introduced into the House by Representatives Jimmy Panetta, Brian Mast, Elissa Slotkin, Will Hurd, with a companion bill introduced into the Senate by Jeff Merkley; the bills called the "Kittens In Traumatic Testing Ends Now Act of 2019", amend the Animal Welfare Act to limit USDA experimentation on cats. The bill has been referred to the Subcommittee on Livestock and Foreign Agriculture of the House Committee on Agriculture. While the bills have not passed, the USDA stated. Title 7 of the Code of Federal Regulations Agricultural Resource Management Survey Germplasm Resources Information Network Human Nutrition Research Center on Aging National Clonal Germplasm Repository National Agricultural Center and Hall of Fame U. S. Horticultural Research Laboratory National Interagency Confederation for Biological Research "Agricultural Research Service".
Archived from the original on October
Forestry is the science and craft of creating, using and repairing forests and associated resources for human and environmental benefits. Forestry is practiced in natural stands; the science of forestry has elements that belong to the biological, social and managerial sciences. Modern forestry embraces a broad range of concerns, in what is known as multiple-use management, including the provision of timber, fuel wood, wildlife habitat, natural water quality management, recreation and community protection, aesthetically appealing landscapes, biodiversity management, watershed management, erosion control, preserving forests as "sinks" for atmospheric carbon dioxide. A practitioner of forestry is known as a forester. Other common terms are: a silviculturalist. Silviculture is narrower than forestry, being concerned only with forest plants, but is used synonymously with forestry. Forest ecosystems have come to be seen as the most important component of the biosphere, forestry has emerged as a vital applied science and technology.
Forestry is an important economic segment in various industrial countries. For example, in Germany, forests cover nearly a third of the land area, wood is the most important renewable resource, forestry supports more than a million jobs and about €181 billion of value to the German economy each year; the preindustrial age has been dubbed by Werner Sombart and others as the'wooden age', as timber and firewood were the basic resources for energy and housing. The development of modern forestry is connected with the rise of capitalism, economy as a science and varying notions of land use and property. Roman Latifundiae, large agricultural estates, were quite successful in maintaining the large supply of wood, necessary for the Roman Empire. Large deforestations came with after the decline of the Romans; however in the 5th century, monks in the Byzantine Romagna on the Adriatic coast, were able to establish stone pine plantations to provide fuelwood and food. This was the beginning of the massive forest mentioned by Dante Alighieri in his 1308 poem Divine Comedy.
Similar sustainable formal forestry practices were developed by the Visigoths in the 7th century when, faced with the ever-increasing shortage of wood, they instituted a code concerned with the preservation of oak and pine forests. The use and management of many forest resources has a long history in China as well, dating back to the Han dynasty and taking place under the landowning gentry. A similar approach was used in Japan, it was later written about by the Ming dynasty Chinese scholar Xu Guangqi. In Europe, land usage rights in medieval and early modern times allowed different users to access forests and pastures. Plant litter and resin extraction were important, as pitch was essential for the caulking of ships and hunting rights and building, timber gathering in wood pastures, for grazing animals in forests; the notion of "commons" refers to the underlying traditional legal term of common land. The idea of enclosed private property came about during modern times. However, most hunting rights were retained by members of the nobility which preserved the right of the nobility to access and use common land for recreation, like fox hunting.
Systematic management of forests for a sustainable yield of timber began in Portugal in the 13th century when Afonso III of Portugal planted the Pinhal do Rei near Leiria to prevent coastal erosion and soil degradation, as a sustainable source for timber used in naval construction. His successor Dom Dinis continued the forest exists still today. Forest management flourished in the German states in the 14th century, e.g. in Nuremberg, in 16th-century Japan. A forest was divided into specific sections and mapped; as timber rafting allowed for connecting large continental forests, as in south western Germany, via Main, Neckar and Rhine with the coastal cities and states, early modern forestry and remote trading were connected. Large firs in the black forest were called "Holländer ``. Large timber rafts on the Rhine were 200 to 400m in length, 40m in width and consisted of several thousand logs; the crew consisted of 400 to 500 men, including shelter, bakeries and livestock stables. Timber rafting infrastructure allowed for large interconnected networks all over continental Europe and is still of importance in Finland.
Starting with the sixteenth century, enhanced world maritime trade, a boom in housing construction in Europe and the success and further Berggeschrey of the mining industry increased timber consumption sharply. The notion of'Nachhaltigkeit', sustainability in forestry, is connected to the work of Hans Carl von Carlowitz, a mining administrator in Saxony, his book Sylvicultura oeconomica, oder haußwirthliche Nachricht und Naturmäßige Anweisung zur wilden Baum-Zucht was the first comprehensive treatise about sustainable yield forestry. In the UK, and, to an extent, in continental Europe, the enclosure movement and the clearances favored enclosed private property; the Agrarian reformers, early economic writers and scientists tried to get rid of the traditional commons. At the time, an alleged tragedy of the commons together with fears of a Holznot, an imminent wood shortage played a watershed role in the controversies about cooperative land use patterns; the practice of establishing tree plantations in the British Isles was promoted by John Evelyn, though it had acquired some populari
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
Picea abies, the Norway spruce or European spruce, is a species of spruce native to Northern and Eastern Europe. It has branchlets that hang downwards, the largest cones of any spruce, 9–17 cm long, it is closely related to the Siberian spruce, which replaces it east of the Ural Mountains, with which it hybridises freely. The Norway spruce is planted for its wood, is the species used as the main Christmas tree in several cities around the world, it was the first gymnosperm to have its genome sequenced, one clone has been measured as 9,560 years old. The Latin specific epithet abies means “fir-like”. Norway spruce is a large, fast-growing evergreen coniferous tree growing 35–55 m tall and with a trunk diameter of 1 to 1.5 m. It can grow fast when young, up to 1 m per year for the first 25 years under good conditions, but becomes slower once over 20 m tall; the shoots are glabrous. The leaves are needle-like with blunt tips, 12–24 mm long, quadrangular in cross-section, dark green on all four sides with inconspicuous stomatal lines.
The seed cones are 9–17 cm long, have bluntly to triangular-pointed scale tips. They are reddish, maturing brown 5 -- 7 months after pollination; the seeds are black, 4–5 mm long, with a pale brown 15-millimetre wing. The tallest grows near Ribnica na Pohorju, Slovenia, it can be observed that the roots of spruces pushed over in a storm form a flat disc. This is due to the rocky subsurface, a high clay content or oxygen-depletion of the subsoil and not to a preference of the trees to form a flat root system; the Norway spruce grows throughout Europe from Norway in the northwest and Poland eastward, in the mountains of central Europe, southwest to the western end of the Alps, southeast in the Carpathians and Balkans to the extreme north of Greece. The northern limit is in the just north of 70 ° N in Norway, its eastern limit in Russia is hard to define, due to extensive hybridisation and intergradation with the Siberian spruce, but is given as the Ural Mountains. However, trees showing some Siberian spruce characters extend as far west as much of northern Finland, with a few records in northeast Norway.
The hybrid is known as Picea × fennica, can be distinguished by a tendency towards having hairy shoots and cones with smoothly rounded scales. Norway spruce cone scales are used as food by the caterpillars of the tortrix moth Cydia illutana, whereas Cydia duplicana feeds on the bark around injuries or canker. Populations in southeast Europe tend to have on average longer cones with more pointed scales. & A. B. Jacks, but there is extensive. Some botanists treat Siberian spruce as a subspecies of Norway spruce, though in their typical forms, they are distinct, the Siberian spruce having cones only 5–10 cm long, with smoothly rounded scales, pubescent shoots. Genetically Norway and Siberian spruces have turned out to be similar and may be considered as two related subspecies of P. abies. Another spruce with smoothly rounded cone scales and hairy shoots occurs in the Central Alps in eastern Switzerland, it is distinct in having thicker, blue-green leaves. Many texts treat this as a variant of Norway spruce, but it is as distinct as many other spruces, appears to be more related to Siberian spruce, Schrenk's spruce from central Asia and Morinda spruce in the Himalaya.
Treated as a distinct species, it takes the name Alpine spruce. As with Siberian spruce, it hybridises extensively with Norway spruce. Hybrids are known as Norwegian spruce, which should not be confused with the pure species Norway spruce; the Norway spruce is one of the most planted spruces, both in and outside of its native range, one of the most economically important coniferous species in Europe. It is used as an ornamental tree in gardens, it is widely planted for use as a Christmas tree. Every Christmas, the Norwegian capital city, provides the cities of London and Washington D. C. with a Norway spruce, placed at the most central square of each city. This is a sign of gratitude for the aid these countries gave during the Second World War. In North America, Norway spruce is planted in the northeastern, Pacific Coast, Rocky Mountain states, as well as in southeastern Canada, it is naturalised in some parts of North America. There are naturalized populations occurring from Connecticut to Michigan, it is probable that they occur elsewhere.
Norway spruces are more tolerant of hot, humid weather than many conifers which do not thrive except in cool-summer areas and they will grow up to USDA Growing Zone 8. Seed production begins when the tree is in its fourth decade and total lifespan is up to 300 years in its natural range in Europe. Introduced Norway spruces in the British Isles and North America have a much shorter life expectancy; as the tree ages, its crown thins out and lower branches die off. In the northern US and Canada, Norway spruce is reported as invasive in some locations, however it does not pose a problem in Zones 6 and up as the seeds have a reduced germination rate in areas with hot, humid s
The Pinophyta known as Coniferophyta or Coniferae, or as conifers, are a division of vascular land plants containing a single extant class, Pinopsida. They are gymnosperms, cone-bearing seed plants. All extant conifers are perennial woody plants with secondary growth; the great majority are trees. Examples include cedars, Douglas firs, firs, kauri, pines, redwoods and yews; as of 1998, the division Pinophyta was estimated to contain eight families, 68 genera, 629 living species. Although the total number of species is small, conifers are ecologically important, they are the dominant plants over large areas of land, most notably the taiga of the Northern Hemisphere, but in similar cool climates in mountains further south. Boreal conifers have many wintertime adaptations; the narrow conical shape of northern conifers, their downward-drooping limbs, help them shed snow. Many of them seasonally alter their biochemistry to make them more resistant to freezing. While tropical rainforests have more biodiversity and turnover, the immense conifer forests of the world represent the largest terrestrial carbon sink.
Conifers are of great economic value for softwood paper production. The earliest conifers in the fossil record date to the late Carboniferous period arising from Cordaites, a genus of seed-bearing Gondwanan plants with cone-like fertile structures. Pinophytes and Ginkgophytes all developed at this time. An important adaptation of these gymnosperms was allowing plants to live without being so dependent on water. Other adaptations are pollen and the seed, which allows the embryo to be transported and developed elsewhere. Conifers appear to be one of the taxa that benefited from the Permian–Triassic extinction event, were the dominant land plants of the Mesozoic, they were overtaken by the flowering plants, which first appeared in the Cretaceous, became dominant in the Cenozoic era. They were the main food of herbivorous dinosaurs, their resins and poisons would have given protection against herbivores. Reproductive features of modern conifers had evolved by the end of the Mesozoic era. Conifer is a Latin word, a compound of conus and ferre, meaning "the one that bears cone".
The division name Pinophyta conforms to the rules of the International Code of Nomenclature for algae and plants, which state that the names of higher taxa in plants are either formed from the name of an included family, in this case Pinaceae, or are descriptive. A descriptive name in widespread use for the conifers is Coniferae. According to the ICN, it is possible to use a name formed by replacing the termination -aceae in the name of an included family, in this case preferably Pinaceae, by the appropriate termination, in the case of this division ‑ophyta. Alternatively, "descriptive botanical names" may be used at any rank above family. Both are allowed; this means that if conifers are considered a division, they may be called Coniferae. As a class they may be called Coniferae; as an order they may be called Coniferae or Coniferales. Conifers are the largest and economically most important component group of the gymnosperms, but they comprise only one of the four groups; the division Pinophyta consists of just one class, which includes both living and fossil taxa.
Subdivision of the living conifers into two or more orders has been proposed from time to time. The most seen in the past was a split into two orders and Pinales, but recent research into DNA sequences suggests that this interpretation leaves the Pinales without Taxales as paraphyletic, the latter order is no longer considered distinct. A more accurate subdivision would be to split the class into three orders, Pinales containing only Pinaceae, Araucariales containing Araucariaceae and Podocarpaceae, Cupressales containing the remaining families, but there has not been any significant support for such a split, with the majority of opinion preferring retention of all the families within a single order Pinales, despite their antiquity and diverse morphology; the conifers are now accepted as comprising seven families, with a total of 65–70 genera and 600–630 species. The seven most distinct families are linked in the box above right and phylogenetic diagram left. In other interpretations, the Cephalotaxaceae may be better included within the Taxaceae, some authors additionally recognize Phyllocladaceae as distinct from Podocarpaceae.
The family Taxodiaceae is here included in family Cupressaceae, but was recognized in the past and can still be found in many field guides. A new classification and linear sequence based on molecular data can be found in an article by Christenhusz et al; the conifers are an ancient group, with a fossil record extending back about 300 million years to the Paleozoic in the late Carboniferous period. Other classes and orders, now long extinct occur as fossils from the late Paleozoic and Mesozoic eras. Fossil conifers included many diverse forms, the most distinct from modern conifers being some herbaceous conifers with no woody stems. Major fossil orders of conifers or conifer-like plants include the Cordaitales, Vojnovskyales and also the Czekanowskiales (possibly