Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic material, a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves, it conveys water and nutrients between the leaves, other growing tissues, the roots. Wood may refer to other plant materials with comparable properties, to material engineered from wood, or wood chips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons and paper. More it emerged as a feedstock for the production of purified cellulose and its derivatives, such as cellophane and cellulose acetate.
As of 2005, the growing stock of forests worldwide was about 434 billion cubic meters, 47% of, commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991 3.5 billion cubic meters of wood were harvested. Dominant uses were for building construction. A 2011 discovery in the Canadian province of New Brunswick yielded the earliest known plants to have grown wood 395 to 400 million years ago. Wood can be dated by carbon dating and in some species by dendrochronology to determine when a wooden object was created. People have used wood for thousands of years for many purposes, including as a fuel or as a construction material for making houses, weapons, packaging and paper. Known constructions using wood date back ten thousand years. Buildings like the European Neolithic long house were made of wood. Recent use of wood has been enhanced by the addition of bronze into construction; the year-to-year variation in tree-ring widths and isotopic abundances gives clues to the prevailing climate at the time a tree was cut.
Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, roots. This process is known as secondary growth; these cells go on to form thickened secondary cell walls, composed of cellulose and lignin. Where the differences between the four seasons are distinct, e.g. New Zealand, growth can occur in a discrete annual or seasonal pattern, leading to growth rings. If the distinctiveness between seasons is annual, these growth rings are referred to as annual rings. Where there is little seasonal difference growth rings are to be indistinct or absent. If the bark of the tree has been removed in a particular area, the rings will be deformed as the plant overgrows the scar. If there are differences within a growth ring the part of a growth ring nearest the center of the tree, formed early in the growing season when growth is rapid, is composed of wider elements.
It is lighter in color than that near the outer portion of the ring, is known as earlywood or springwood. The outer portion formed in the season is known as the latewood or summerwood. However, there are major differences, depending on the kind of wood; as a tree grows, lower branches die, their bases may become overgrown and enclosed by subsequent layers of trunk wood, forming a type of imperfection known as a knot. The dead branch may not be attached to the trunk wood except at its base, can drop out after the tree has been sawn into boards. Knots affect the technical properties of the wood reducing the local strength and increasing the tendency for splitting along the wood grain, but may be exploited for visual effect. In a longitudinally sawn plank, a knot will appear as a circular "solid" piece of wood around which the grain of the rest of the wood "flows". Within a knot, the direction of the wood is up to 90 degrees different from the grain direction of the regular wood. In the tree a knot is either the base of a dormant bud.
A knot is conical in shape with the inner tip at the point in stem diameter at which the plant's vascular cambium was located when the branch formed as a bud. In grading lumber and structural timber, knots are classified according to their form, size and the firmness with which they are held in place; this firmness is affected by, among other factors, the length of time for which the branch was dead while the attaching stem continued to grow. Knots materially affect cracking and warping, ease in working, cleavability of timber, they are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious when timber is subjected to forces perpendicular to the grain and/or tension than when under load along the grain and/or compression; the extent to which knots affect the strength of a beam depends upon their position, size and condition. A knot on the upper side is compressed. If there is a season check
Mexico the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States. Covering 2,000,000 square kilometres, the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity, the capital city and its most populous city. Other metropolises in the state include Guadalajara, Puebla, Tijuana and León. Pre-Columbian Mexico dates to about 8000 BC and is identified as one of five cradles of civilization and was home to many advanced Mesoamerican civilizations such as the Olmec, Teotihuacan, Zapotec and Aztec before first contact with Europeans. In 1521, the Spanish Empire conquered and colonized the territory from its politically powerful base in Mexico-Tenochtitlan, administered as the viceroyalty of New Spain.
Three centuries the territory became a nation state following its recognition in 1821 after the Mexican War of Independence. The post-independence period was tumultuous, characterized by economic inequality and many contrasting political changes; the Mexican–American War led to a territorial cession of the extant northern territories to the United States. The Pastry War, the Franco-Mexican War, a civil war, two empires, the Porfiriato occurred in the 19th century; the Porfiriato was ended by the start of the Mexican Revolution in 1910, which culminated with the promulgation of the 1917 Constitution and the emergence of the country's current political system as a federal, democratic republic. Mexico has the 11th largest by purchasing power parity; the Mexican economy is linked to those of its 1994 North American Free Trade Agreement partners the United States. In 1994, Mexico became the first Latin American member of the Organisation for Economic Co-operation and Development, it is classified as an upper-middle income country by the World Bank and a newly industrialized country by several analysts.
The country is considered both a regional power and a middle power, is identified as an emerging global power. Due to its rich culture and history, Mexico ranks first in the Americas and seventh in the world for number of UNESCO World Heritage Sites. Mexico is an ecologically megadiverse country, ranking fourth in the world for its biodiversity. Mexico receives a huge number of tourists every year: in 2018, it was the sixth most-visited country in the world, with 39 million international arrivals. Mexico is a member of the United Nations, the World Trade Organization, the G8+5, the G20, the Uniting for Consensus group of the UN, the Pacific Alliance trade bloc. Mēxihco is the Nahuatl term for the heartland of the Aztec Empire, namely the Valley of Mexico and surrounding territories, with its people being known as the Mexica, it is believed to be a toponym for the valley which became the primary ethnonym for the Aztec Triple Alliance as a result, although it could have been the other way around.
In the colonial era, back when Mexico was called New Spain this territory became the Intendency of Mexico and after New Spain achieved independence from the Spanish Empire it came to be known as the State of Mexico with the new country being named after its capital: the City of Mexico, which itself was founded in 1524 on top of the ancient Mexica capital of Mexico-Tenochtitlan. Traditionally, the name Tenochtitlan was thought to come from Nahuatl tetl and nōchtli and is thought to mean "Among the prickly pears rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggests the second vowel was short, so that the true etymology remains uncertain; the suffix -co is the Nahuatl locative, making the word a place name. Beyond that, the etymology is uncertain, it has been suggested that it is derived from Mextli or Mēxihtli, a secret name for the god of war and patron of the Mexica, Huitzilopochtli, in which case Mēxihco means "place where Huitzilopochtli lives".
Another hypothesis suggests that Mēxihco derives from a portmanteau of the Nahuatl words for "moon" and navel. This meaning might refer to Tenochtitlan's position in the middle of Lake Texcoco; the system of interconnected lakes, of which Texcoco formed the center, had the form of a rabbit, which the Mesoamericans pareidolically associated with the moon rabbit. Still another hypothesis suggests that the word is derived from Mēctli, the name of the goddess of maguey; the name of the city-state was transliterated to Spanish as México with the phonetic value of the letter x in Medieval Spanish, which represented the voiceless postalveolar fricative. This sound, as well as the voiced postalveolar fricative, represented by a j, evolved into a voiceless velar fricative during the 16th century; this led to the use of the variant Méjico in many publications in Spanish, most notably in Spain, whereas in Mexico and most other Spanish–speaking countries, México was the preferred spelling. In recent years, the Real Academia Española, which regulates the Spanish l
Late Latin is the scholarly name for the written Latin of late antiquity. English dictionary definitions of Late Latin date this period from the 3rd to the 6th centuries AD, continuing into the 7th century in the Iberian Peninsula; this somewhat ambiguously defined version of Latin was used between the eras of Classical Latin and Medieval Latin. There is no scholarly consensus about when Classical Latin should end or Medieval Latin should begin. However, Late Latin is characterized by an identifiable style. Being a written language, Late Latin is not the same as Vulgar Latin; the latter served as ancestor of the Romance languages. Although Late Latin reflects an upsurge of the use of Vulgar Latin vocabulary and constructs, it remains classical in its overall features, depending on the author who uses it; some Late Latin writings are more literary and classical, but others are more inclined to the vernacular. Late Latin is not identical to Christian patristic Latin, used in the theological writings of the early Christian fathers.
While Christian writings used a subset of Late Latin, pagans wrote extensively in Late Latin in the early part of the period. Late Latin formed when mercenaries from non-Latin-speaking peoples on the borders of the empire were being subsumed and assimilated in large numbers, the rise of Christianity was introducing a heightened divisiveness in Roman society, creating a greater need for a standard language for communicating between different socioeconomic registers and separated regions of the sprawling empire. A new and more universal speech evolved from the main elements: Classical Latin, Christian Latin, which featured sermo humilis in which the people were to be addressed, all the various dialects of Vulgar Latin; the linguist Antoine Meillet wrote, "Without the exterior appearance of the language being much modified, Latin became in the course of the imperial epoch a new language", and, "Serving as some sort of lingua franca to a large empire, Latin tended to become simpler, to keep above all what it had of the ordinary".
Neither Late Latin nor Late Antiquity are modern concepts. A notice in Harper's New Monthly Magazine of the publication of Andrews' Freund's Lexicon of the Latin Language in 1850 mentions that the dictionary divides Latin into ante-classic, quite classic, Augustan, post-Augustan and post-classic or late Latin, which indicates the term was in professional use by English classicists in the early 19th century. Instances of English vernacular use of the term may be found from the 18th century; the term Late Antiquity meaning post-classical and pre-medieval had currency in English well before then. Wilhelm Sigismund Teuffel's first edition of History of Roman Literature defined an early period, the Golden Age, the Silver Age and goes on to define other ages first by dynasty and by century. In subsequent editions he subsumed all periods under three headings: the First Period, the Second Period and the Third Period, "the Imperial Age", subdivided into the Silver Age, the 2nd century, Centuries 3–6 together, a recognition of Late Latin, as he sometimes refers to the writings of those times as "late."
Imperial Latin went on into English literature. There are, insoluble problems with the beginning and end of Imperial Latin. Politically the excluded Augustan Period is the paradigm of imperiality, yet the style cannot be bundled with either the Silver Age or with Late Latin. Moreover, in 6th century Italy, the Roman Empire no longer existed. Subsequently the term Imperial Latin was dropped by historians of Latin literature, although it may be seen in marginal works; the Silver Age was extended the final four centuries represent Late Latin. Low Latin is a vague and pejorative term that might refer to any post-classical Latin from Late Latin through Renaissance Latin depending on the author, its origins are obscure but the Latin expression media et infima Latinitas sprang into public notice in 1678 in the title of a Glossary by Charles du Fresne, sieur du Cange. The multi-volume set had many expansions by other authors subsequently; the title varies somewhat. It has been translated by expressions of different meanings.
The uncertainty is understanding what media, "middle", infima, "low", mean in this context. The media is securely connected to Medieval Latin by Cange's own terminology expounded in the Praefatio, such as scriptores mediae aetatis, "writers of the middle age." Cange's Glossary takes words from authors ranging from the Christian period to the Renaissance, dipping into the classical period if a word originated there. Either media et infima Latinitas refers to one age, which must be the middle age covering the entire post-classical range, or it refers to two consecutive periods, infima Latinitas and media Latinitas. Both interpretations have their adherents. In the former case the infimae appears extraneous; the two-period case postulates a second unity of style, infima Latinitas, translated into English as "Low Latin". Cange in the glossarial part of his Glossary identifies some words as being used by purioris Latinitatis scriptores, such as Cicero, he has said in the Preface that he rejects the a
Prosopis juliflora is a shrub or small tree in the family Fabaceae, a kind of mesquite. It is native to South America and the Caribbean, it has become established as an invasive weed in Africa, Asia and elsewhere. It is a contributing factor to continuing transmission of malaria during dry periods when sugar sources from native plants are unavailable to mosquitoes. Growing to a height of up to 12 metres, P. juliflora has a trunk diameter of up to 1.2 metres. Its leaves are geminate-pinnate, light green, with 12 to 20 leaflets. Flowers appear shortly after leaf development; the flowers are in 5–10 cm long green-yellow cylindrical spikes, which occur in clusters of 2 to 5 at the ends of branches. Pods contain between 10 and 30 seeds per pod. A mature plant can produce hundreds of thousands of seeds. Seeds remain viable for up to 10 years; the tree reproduces by way of seeds, not vegetatively. Seeds are spread by cattle and other animals, which consume the seed pods and spread the seeds in their droppings.
Its roots are able to grow to a great depth in search of water: in 1960, they were discovered at a depth of 53 meters at an open-pit mine near Tucson, putting them among the deepest known roots. The tree is said to have been introduced to Sri Lanka in the 19th century, where it is now known as vanni-andara, or katu andara in Sinhala, it is claimed that P. juliflora existed and was recognised as a holy tree in ancient India, but this is most a confusion with Prosopis cineraria. The tree is believed to have existed in the Mannar regions for a long time; this species has thorns in pairs at the nodes. The species has variable thorniness, with nearly thornless individuals appearing occasionally. In the western extent of its range in Ecuador and Peru, Prosopis juliflora hybridises with Prosopis pallida and can be difficult to distinguish from this similar species or their interspecific hybrid strains, its uses include forage and environmental management. The plant possesses an unusual amount of the flavanol -mesquitol in its heartwood.
In the Macará Canton of Ecuador, Prosopis juliflora can be found in dry forests where it is one of the species most harvested for multiple forest products. Prosopis juliflora has become an invasive weed in several countries, it is considered a noxious invader in Ethiopia, Sri Lanka, Kenya, the Middle East, Nigeria, Somalia and Southern Africa. It is a major weed in the southwestern United States, it is expensive to remove as the plant can regenerate from the roots. In Australia, mesquite has colonized more than 800,000 hectares of arable land, having severe economic and environmental impacts. With its thorns and many low branches it forms impenetrable thickets which prevent cattle from accessing watering holes, etc, it takes over pastoral grasslands and uses scarce water. Livestock which consume excessive amounts of seed pods are poisoned due to neurotoxic alkaloids, it causes land erosion due to the loss of the grasslands that are habitats for native plants and animals. It provides shelter for feral animals such as pigs and cats.
In the Afar Region in Ethiopia, where the mesquite was introduced in the late 1970s and early 1980s, its aggressive growth leads to a monoculture, denying native plants water and sunlight, not providing food for native animals and cattle. The regional government with the non-governmental organisation FARM-Africa are looking for ways to commercialize the tree's wood, but pastoralists who call it the "Devil Tree" insist that P. juliflora be eradicated. In Sri Lanka this mesquite was planted in the 1950s near Hambantota as a shade and erosion control tree, it invaded the grasslands in and around Hambantota and the Bundala National Park, causing similar problems as in Australia and Ethiopia. This mesquite Prosopis juliflora native to Central and South America, is known as katu andara, it has become a serious problem as an invasive species. Prosopis juliflora has a wide range of vernacular names, although no used English one except for mesquite, used for several species of Prosopis, it is called bayahonda blanca in Spanish, bayarone Français in French, bayawonn in Creole.
Other similar names are used, including bayahonde and bayarone, but these may refer to any other Neotropical member of the genus Prosopis. The tree is known by a range of other names in various parts of the world, including algarrobe, cambrón, cashaw, épinard, mostrenco, or mathenge. Many of the less-specific names are because over large parts of its range, it is the most familiar and common species of Prosopis, thus to locals "the" bayahonde, etc. "Velvet mesquite" is sometimes given as an English name, but properly refers to a different species, Prosopis velutina. Names in and around Indian Subcontinent, where the species is used for firewood and to make barriers compare it to similar trees and note its introduced status; the angaraji and vilayati names mean they were introduced by Europeans, while Kabuli kikar means "Kabul acacia". In Gujarati it is in Marwari, baavlia. In Karnataka, in Kannada it is known as Ballaari Jaali meaning "Jaali", local name, abundant in and around Bellary district.
In Tamil Nadu, in Tamil language it is known as seemai karuvel (சீமைக்
Plants are multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Plants were treated as one of two kingdoms including all living things that were not animals, all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants and other gymnosperms and their allies, liverworts and the green algae, but excludes the red and brown algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria, their chloroplasts contain b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is common.
There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants. Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecosystems on land. Plants that produce grain and vegetables form humankind's basic foods, have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs; the scientific study of plants is known as a branch of biology. All living things were traditionally placed into one of two groups and animals; this classification may date from Aristotle, who made the distincton between plants, which do not move, animals, which are mobile to catch their food. Much when Linnaeus created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia and Animalia. Since it has become clear that the plant kingdom as defined included several unrelated groups, the fungi and several groups of algae were removed to new kingdoms.
However, these organisms are still considered plants in popular contexts. The term "plant" implies the possession of the following traits multicellularity, possession of cell walls containing cellulose and the ability to carry out photosynthesis with primary chloroplasts; when the name Plantae or plant is applied to a specific group of organisms or taxon, it refers to one of four concepts. From least to most inclusive, these four groupings are: Another way of looking at the relationships between the different groups that have been called "plants" is through a cladogram, which shows their evolutionary relationships; these are not yet settled, but one accepted relationship between the three groups described above is shown below. Those which have been called "plants" are in bold; the way in which the groups of green algae are combined and named varies between authors. Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom.
The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the green algae, red algae and brown algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, they are no longer classified as plants as defined here; the Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions, the green plants have the following features in common, they undergo closed mitosis without centrioles, have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria. Two additional groups, the Rhodophyta and Glaucophyta have primary chloroplasts that appear to be derived directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in the pigments which are used in photosynthesis and so are different in colour.
These groups differ from green plants in that the storage polysaccharide is floridean starch and is stored in the cytoplasm rather than in the plastids. They appear to have had a common origin with Viridiplantae and the three groups form the clade Archaeplastida, whose name implies that their chloroplasts were derived from a single ancient endosymbiotic event; this is the broadest modern definition of the term'plant'. In contrast, most other algae not only have different pigments but have chloroplasts with three or four surrounding membranes, they are not close relatives of the Archaeplastida having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in the broadest modern definition of the plant kingdom, although they were in the past; the green plants or Viridiplantae were traditionally divided into the green algae (including
Augustin Pyramus de Candolle
Augustin Pyramus de Candolle spelled Augustin Pyrame de Candolle was a Swiss botanist. René Louiche Desfontaines launched de Candolle's botanical career by recommending him at an herbarium. Within a couple of years de Candolle had established a new genus, he went on to document hundreds of plant families and create a new natural plant classification system. Although de Candolle's main focus was botany, he contributed to related fields such as phytogeography, paleontology, medical botany, economic botany. Candolle originated the idea of "Nature's war", which influenced Charles Darwin and the principle of natural selection. De Candolle recognized that multiple species may develop similar characteristics that did not appear in a common evolutionary ancestor. During his work with plants, de Candolle noticed that plant leaf movements follow a near-24-hour cycle in constant light, suggesting that an internal biological clock exists. Though many scientists doubted de Candolle's findings, experiments over a century demonstrated that ″the internal biological clock″ indeed exists.
Candolle's descendants continued his work on plant classification. Alphonse de Candolle and Casimir Pyrame de Candolle contributed to the Prodromus Systematis Naturalis Regni Vegetabilis, a catalog of plants begun by Augustin Pyramus de Candolle. Augustin Pyramus de Candolle was born on 4 February 1778 in Geneva, Switzerland, to Augustin de Candolle, a former official, his wife, Louise Eléonore Brière, his family descended from one of the ancient families of Provence in France, but relocated to Geneva at the end of the 16th century to escape religious persecution. At age seven de Candolle contracted of a severe case of hydrocephalus, which affected his childhood, he is said to have had great aptitude for learning, distinguishing himself in school with his rapid acquisition of knowledge in classical and general literature and his ability to write fine poetry. In 1794, he began his scientific studies at the Collège Calvin, where he studied under Jean Pierre Étienne Vaucher, who inspired de Candolle to make botanical science the chief pursuit of his life.
He spent four years at the Geneva Academy, studying science and law according to his father's wishes. In 1798, he moved to Paris, his botanical career formally began with the help of René Louiche Desfontaines, who recommended de Candolle for work in the herbarium of Charles Louis L'Héritier de Brutelle during the summer of 1798. The position elevated de Candolle's reputation and led to valuable instruction from Desfontaines himself. De Candolle established his first genus, Senebiera, in 1799.de Candolle's first books, Plantarum historia succulentarum and Astragalogia, brought him to the notice of Georges Cuvier and Jean-Baptiste Lamarck. de Candolle, with Cuvier's approval, acted as deputy at the Collège de France in 1802. Lamarck entrusted him with the publication of the third edition of the Flore française, in the introduction entitled Principes élémentaires de botanique, de Candolle proposed a natural method of plant classification as opposed to the artificial Linnaean method; the premise of de Candolle's method is.
In 1804, de Candolle published his Essai sur les propriétés médicales des plantes and was granted a doctor of medicine degree by the medical faculty of Paris. Two years he published Synopsis plantarum in flora Gallica descriptarum. de Candolle spent the next six summers making a botanical and agricultural survey of France at the request of the French government, published in 1813. In 1807 he was appointed professor of botany in the medical faculty of the University of Montpellier, where he would become the first chair of botany in 1810, his teaching at the University of Montpellier consisted of field classes attended by 200–300 students, starting at 5:00 am and finishing at 7:00 pm. While in Montpellier, de Candolle published his Théorie élémentaire de la botanique, which introduced a new classification system and the word taxonomy. Candolle moved back to Geneva in 1816 and in the following year was invited by the government of the Canton of Geneva to fill the newly created chair of natural history.
De Candolle spent the rest of his life in an attempt to elaborate and complete his natural system of botanical classification. De Candolle published initial work in his Regni vegetabillis systema naturale, but after two volumes he realized he could not complete the project on such a large scale, he began his less extensive Prodromus Systematis Naturalis Regni Vegetabilis in 1824. However, he was able to finish two-thirds of the whole. So, he was able to characterize over one hundred families of plants, helping to lay the empirical basis of general botany. Although de Candolle's main focus was botany, throughout his career he dabbled in fields related to botany, such as phytogeography, paleontology, medical botany, economic botany. In 1827 he was elected an associated member of the Royal Institute of the Netherlands. Augustin de Candolle was the first of four generations of botanists in the de Candolle dynasty, his son, Alphonse de Candolle, whom he fathered with his wife, Mademoiselle Torras succeeded to his father's chair in botany and continued the Prodromus.
Casimir Pyrame de Candolle, Augustin de Candolle's grandson contributed to the Prodromus through his detailed, extensive research and characterization of the Piperaceae family of plants. Augustin de Candolle's great-grandson, Richard Émile Augustin de Candolle
The pea is most the small spherical seed or the seed-pod of the pod fruit Pisum sativum. Each pod contains several peas, which can be yellow. Pea pods are botanically fruit, since they develop from the ovary of a flower; the name is used to describe other edible seeds from the Fabaceae such as the pigeon pea, the cowpea, the seeds from several species of Lathyrus. P. sativum is an annual plant, with a life cycle of one year. It is a cool-season crop grown in many parts of the world; the average pea weighs between 0.36 gram. The immature peas are used as a vegetable, frozen or canned; these are the basis of staples of medieval cuisine. The wild pea is restricted to the Near East; the earliest archaeological finds of peas date from the late neolithic era of current Greece, Syria and Jordan. In Egypt, early finds date from c. 4800–4400 BC in the Nile delta area, from c. 3800–3600 BC in Upper Egypt. The pea was present in Georgia in the 5th millennium BC. Farther east, the finds are younger. Peas were present in Afghanistan c. 2000 BC.
In the second half of the 2nd millennium BC, this pulse crop appears in the Ganges Basin and southern India. A pea is a most green golden yellow, or infrequently purple pod-shaped vegetable grown as a cool season vegetable crop; the seeds may be planted as soon as the soil temperature reaches 10 °C, with the plants growing best at temperatures of 13 to 18 °C. They do not thrive in the summer heat of warmer temperate and lowland tropical climates, but do grow well in cooler, high altitude, tropical areas. Many cultivars reach maturity about 60 days after planting. Peas have vining cultivars; the vining cultivars grow thin tendrils from leaves that coil around any available support and can climb to be 1–2 m high. A traditional approach to supporting climbing peas is to thrust branches pruned from trees or other woody plants upright into the soil, providing a lattice for the peas to climb. Branches used in this fashion are sometimes called pea brush. Metal fences, twine, or netting supported by a frame are used for the same purpose.
In dense plantings, peas give each other some measure of mutual support. Pea plants can self-pollinate. In early times, peas were grown for their dry seeds. From plants growing wild in the Mediterranean basin, constant selection since the Neolithic dawn of agriculture improved their yield. In the early 3rd century BC Theophrastus mentions peas among the pulses that are sown late in the winter because of their tenderness. In the first century AD, Columella mentions them in De re rustica, when Roman legionaries still gathered wild peas from the sandy soils of Numidia and Judea to supplement their rations. In the Middle Ages, field peas are mentioned, as they were the staple that kept famine at bay, as Charles the Good, count of Flanders, noted explicitly in 1124. Green "garden" peas, eaten immature and fresh, were an innovative luxury of Early Modern Europe. In England, the distinction between field peas and garden peas dates from the early 17th century: John Gerard and John Parkinson both mention garden peas.
Sugar peas, which the French soon called mange-tout, for they were consumed pods and all, were introduced to France from the market gardens of Holland in the time of Henri IV, through the French ambassador. Green peas were introduced from Genoa to the court of Louis XIV of France in January 1660, with some staged fanfare. Established and grown for earliness warmed with manure and protected under glass, they were still a luxurious delicacy in 1696, when Mme de Maintenon and Mme de Sevigné each reported that they were "a fashion, a fury."Modern split peas, with their indigestible skins rubbed off, are a development of the 19th century. In modern times peas are boiled or steamed, which breaks down the cell walls and makes the taste sweeter and the nutrients more bioavailable. Along with broad beans and lentils, these formed an important part of the diet of most people in the Middle East, North Africa and Europe during the Middle Ages. By the 17th and 18th centuries, it had become popular to eat peas "green", that is, while they are immature and right after they are picked.
New cultivars of peas were developed by the English during this time, which became known as "garden" or "English" peas. The popularity of green peas spread to North America. Thomas Jefferson grew more than 30 cultivars of peas on his estate. With the invention of canning and freezing of foods, green peas became available year-round, not just in the spring as before. Fresh peas are eaten boiled and flavored with butter and/or spearmint as a side dish vegetable. Salt and pepper are commonly added to peas when served. Fresh peas are used in pot pies and casseroles. Pod peas are used in stir-fried dishes those in A