1.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
2.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
3.
Flowering plant
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The flowering plants, also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approx. 13,164 known genera and a total of c.295,383 known species, etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term angiosperm comes from the Greek composite word meaning enclosed seeds, the ancestors of flowering plants diverged from gymnosperms in the Triassic Period, during the range 245 to 202 million years ago, and the first flowering plants are known from 160 mya. They diversified extensively during the Lower Cretaceous, became widespread by 120 mya, angiosperms differ from other seed plants in several ways, described in the table. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants, the amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings, in the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium, the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Among the monocotyledons, the bundles are more numerous in the stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases, the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species, the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf, occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. There are two kinds of cells produced by flowers. Microspores, which divide to become pollen grains, are the male cells and are borne in the stamens. The female cells called megaspores, which divide to become the egg cell, are contained in the ovule. The flower may consist only of parts, as in willow. Usually, other structures are present and serve to protect the sporophylls, the individual members of these surrounding structures are known as sepals and petals. The outer series is usually green and leaf-like, and functions to protect the rest of the flower, the inner series is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators, attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower
4.
Eudicots
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The eudicots, Eudicotidae or eudicotyledons are a monophyletic clade of flowering plants that had been called tricolpates or non-magnoliid dicots by previous authors. The close relationships among flowering plants with tricolpate pollen grains was initially seen in studies of shared derived characters. These plants have a trait in their pollen grains of exhibiting three colpi or grooves paralleling the polar axis. Later molecular evidence confirmed the basis for the evolutionary relationships among flowering plants with tricolpate pollen grains. The term means true dicotyledons, as it contains the majority of plants that have been considered dicots and have characteristics of the dicots, the term eudicots has subsequently been widely adopted in botany to refer to one of the two largest clades of angiosperms, monocots being the other. The remaining angiosperms are sometimes referred to as basal angiosperms or paleodicots, the other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen, or forms derived from it and these pollens have three or more pores set in furrows called colpi. In contrast, most of the seed plants produce monosulcate pollen. The name tricolpates is preferred by some botanists to avoid confusion with the dicots, numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Most leafy trees of midlatitudes also belong to eudicots, with exceptions being magnolias and tulip trees which belong to magnoliids, and Ginkgo biloba. The name eudicots is used in the APG system, of 1998 and it is applied to a clade, a monophyletic group, which includes most of the dicots. The eudicots can be divided into two groups, the basal eudicots and the core eudicots, basal eudicot is an informal name for a paraphyletic group. The core eudicots are a monophyletic group, a 2010 study suggested the core eudicots can be divided into two clades, Gunnerales and a clade called Pentapetalae, comprising all the remaining core eudicots
5.
Rosids
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The rosids are members of a large clade of flowering plants, containing about 70,000 species, more than a quarter of all angiosperms. The clade is divided into 16 to 20 orders, depending upon circumscription and classification and these orders, in turn, together comprise about 140 families. Fossil rosids are known from the Cretaceous period, molecular clock estimates indicate that the rosids originated in the Aptian or Albian stages of the Cretaceous, between 125 and 99.6 million years ago. The name is based upon the name Rosidae, which had usually been understood to be a subclass, in 1967, Armen Takhtajan showed that the correct basis for the name Rosidae is a description of a group of plants published in 1830 by Friedrich Gottlieb Bartling. The clade was later renamed Rosidae and has been variously delimited by different authors, the name rosids is informal and not assumed to have any particular taxonomic rank like the names authorized by the ICBN. The rosids are monophyletic based upon evidence found by molecular phylogenetic analysis, three different definitions of the rosids were used. Some authors included the orders Saxifragales and Vitales in the rosids, others excluded both of these orders. The circumscription used in this article is that of the APG IV classification, which includes Vitales, the rosids and Saxifragales form the superrosids clade. This is one of three groups compose the Pentapetalae, the others being Dilleniales and the superasterids. The rosids consist of two groups, the order Vitales and the eurosids, the eurosids, in turn, are divided into two groups, fabids and malvids. The rosids consist of 17 orders, in addition to Vitales, there are 8 orders in fabids and 8 orders in malvids. Some of the orders have only recently been recognized and these are Vitales, Zygophyllales, Crossosomatales, Picramniales, and Huerteales. The phylogeny of Rosids shown below is adapted from the Angiosperm Phylogeny Group website, the nitrogen-fixing clade contains a high number of actinorhizal plants. Not all plants in this clade are actinorhizal, however, media related to Rosids at Wikimedia Commons
6.
Brassicales
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The Brassicales are an order of flowering plants, belonging to the eurosids II group of dicotyledons under the APG II system. One character common to members of the order is the production of glucosinolate compounds. Most systems of classification have included this order, although sometimes under the name Capparales, the only families included were the Brassicaceae and Capparaceae, the Tovariaceae, Resedaceae, and Moringaceae. Other taxa now included here were placed in other orders. The families Capparaceae and Brassicaceae are closely related, one group, consisting of Cleome and related genera, was traditionally included in the Capparaceae but doing so results in a paraphyletic Capparaceae. Therefore, this group is now either included in the Brassicaceae or as its own family. Media related to Brassicales at Wikimedia Commons
7.
Brassicaceae
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Brassicaceae or Cruciferae is a medium-sized and economically important family of flowering plants commonly known as the mustards, the crucifers, or the cabbage family. The name Brassicaceae is derived from the included genus Brassica, the alternative older name, Cruciferae, meaning cross-bearing, describes the four petals of mustard flowers, which resemble a cross. Cruciferae is one of eight plant family names without the suffix -aceae that are authorized alternative names, the family contains 372 genera and 4060 accepted species. The largest genera are Draba, Erysimum, Lepidium, Cardamine, pieris rapae and other butterflies of the family Pieridae are some of the best-known pests of Brassicaceae species planted as commercial crops. The family is included in the Brassicales according to the APG system, older systems placed them into the Capparales, a now-defunct order that had a similar definition. This family comprises about 375 genera and 2500 species all over the world,94 species of 38 genera are found in Nepal, a close relationship has long been acknowledged between the Brassicaceae and the caper family, Capparaceae, in part because members of both groups produce glucosinolate compounds. The APG II system, therefore, has merged the two families under the name Brassicaceae, the APG III system has recently adopted this last solution, but this may change as a consensus arises on this point. This article deals with Brassicaceae sensu stricto, i. e. treating the Cleomaceae and Capparaceae as segregated families, the family consists mostly of herbaceous plants with annual, biennial, or perennial lifespans. The leaves are alternate, sometimes organized in basal rosettes, in rare shrubby crucifers of Mediterranean their leaves are mostly in terminal rosettes and they are very often pinnately incised and do not have stipules. The structure of the flowers is extremely uniform throughout the family and they have four free saccate sepals and four clawed free petals, staggered. They can be disymmetric or slightly zygomorphic, with a typical cross-like arrangement and they have six stamens, four of which are longer and are arranged in a cross like the petals and the other two are shorter. The pistil is made up of two fused carpels and the style is short, with two lobes. The flowers form ebracteate racemose inflorescences, often apically corymb-like, pollination occurs by entomogamy, nectar is produced at the base of the stamens and stored on the sepals. The fruit is a kind of capsule named siliqua. It opens by two valves, which are the modified carpels, leaving the attached to a framework made up of the placenta. Often, an indehiscent beak occurs at the top of the style, where a siliqua is less than three times as long as it is broad, it is usually termed a silicula. The siliqua may break apart at constrictions occurring between the segments of the seeds, thus forming a sort of loment, it may eject the seeds explosively or may be evolved in a sort of samara. The fruit is often the most important diagnostic character for plants in this family, most members share a suite of glucosinolate compounds that have a typical pungent odour usually associated with cole crops
8.
Binomial nomenclature
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Such a name is called a binomial name, a binomen, binominal name or a scientific name, more informally it is also called a Latin name. The first part of the name identifies the genus to which the species belongs, for example, humans belong to the genus Homo and within this genus to the species Homo sapiens. The formal introduction of system of naming species is credited to Carl Linnaeus. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus. Although the general principles underlying binomial nomenclature are common to these two codes, there are differences, both in the terminology they use and in their precise rules. Similarly, both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a name is usually given, at least when it is first mentioned. In zoology Patella vulgata Linnaeus,1758, the original name given by Linnaeus was Fringilla domestica, the parentheses indicate that the species is now considered to belong in a different genus. The ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, in botany Amaranthus retroflexus L. – L. is the standard abbreviation used in botany for Linnaeus. – Linnaeus first named this bluebell species Scilla italica, Rothmaler transferred it to the genus Hyacinthoides, the ICN does not require that the dates of either publication be specified. Prior to the adoption of the binomial system of naming species. Together they formed a system of polynomial nomenclature and these names had two separate functions. First, to designate or label the species, and second, to be a diagnosis or description, such polynomial names may sometimes look like binomials, but are significantly different. For example, Gerards herbal describes various kinds of spiderwort, The first is called Phalangium ramosum, Branched Spiderwort, is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia. The Latin phrases are short descriptions, rather than identifying labels, the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné. It was in his 1753 Species Plantarum that he first began using a one-word trivial name together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as an epithet or specific name
9.
Robert Brown (botanist, born 1773)
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Robert Brown FRSE FRS FLS MWS was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope. Brown was born in Montrose on 21 December 1773 and he was the son of James Brown, a minister in the Scottish Episcopal Church with Jacobite convictions so strong that in 1788 he defied his churchs decision to give allegiance to George III. His mother was Helen née Taylor, the daughter of a Presbyterian minister, as a child Brown attended the local Grammar School, then Marischal College at Aberdeen, but withdrew in his fourth year when the family moved to Edinburgh in 1790. His father died late the following year, Brown enrolled to study medicine at the University of Edinburgh, but developed an interest in botany, and ended up spending more of his time on the latter than the former. He also began corresponding with and collecting for William Withering, one of the foremost British botanists of his day, Brown dropped out of his medical course in 1793. Late in 1794, he enlisted in the Fifeshire Fencibles, in June 1795 he was appointed Surgeons Mate. His regiment saw little action, however, he had a good deal of leisure time. During this period Brown was especially interested in cryptogams, and these would be the subject of Browns first, albeit unattributed, Brown began a correspondence with James Dickson, and by 1796 was sending him specimens and descriptions of mosses. Dickson incorporated Browns descriptions into his Fasciculi plantarum cryptogamicarum britanniae, with Browns permission and he had also begun experimenting with microscopy. However, as a surgeon stationed in Ireland there seemed little prospect of him attracting the notice of those who could offer him a career in botany. In 1798, Brown heard that Mungo Park had withdrawn from an expedition into the interior of New Holland. At Browns request, Correia wrote to Sir Joseph Banks, suggesting Brown as a replacement, Science is the gainer in this change of man. He is a Scotchman, fit to pursue an object with constance and he was not selected, and the expedition did not end up going ahead as originally proposed, though George Caley was sent to New South Wales as a botanical collector for Banks. In 1800, however, Matthew Flinders put to Banks a proposal for an expedition that would answer the question whether New Holland was one island or several, Banks approved Flinders proposal, and in December 1800 wrote to Brown offering him the position of naturalist to the expedition. Brown was told to expect to sail at the end of 1800, a succession of delays meant the voyage did not get under way until July 1801. Brown spent much of the meantime preparing for the voyage by studying Banks Australian plant specimens and copying out notes and descriptions for use on the voyage. Though Browns brief was collect scientific specimens of all sorts, he was told to give priority to plants, insects, and birds, and to treat other fields, such as geology, as secondary pursuits. Brown was given authority over Bauer and Good, both of whom were instructed to give any specimens they collect to Brown, rather than forming separate collections
10.
Hook.f.
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Sir Joseph Dalton Hooker OM GCSI CB PRS was one of the greatest British botanists and explorers of the 19th century. He was a founder of botany and Charles Darwins closest friend. For twenty years he served as director of the Royal Botanical Gardens, Kew, succeeding his father, William Jackson Hooker, Hooker was born in Halesworth, Suffolk, England. From age seven, Hooker attended his fathers lectures at Glasgow University, taking an early interest in plant distribution and he was educated at the Glasgow High School and went on to study medicine at Glasgow University, graduating M. D. in 1839. In 1851 he married Frances Harriet Henslow, daughter of Darwins mentor and they had four sons and three daughters, William Henslow Hooker Harriet Anne Hooker married William Turner Thiselton-Dyer Charles Paget Hooker Maria Elizabeth Hooker died aged 6. Brian Harvey Hodgson Hooker Reginald Hawthorn Hooker statistician Grace Ellen Hooker Frances Harriet Henslows contribution to his work included translating French botanical texts which Hooker edited. After his first wifes death in 1874, in 1876 he married Lady Hyacinth Jardine, daughter of William Samuel Symonds and they had two sons, Joseph Symonds Hooker Richard Symonds Hooker. Joseph Hooker died in his sleep at midnight at home, the Camp, Sunningdale in Berkshire, on 10 December 1911 after a short, the Dean and Chapter of Westminster Abbey offered a grave near Darwins in the nave but also insisted that Hooker be cremated before. His memorial tablet in the church, with a motif of five plants, was designed by Matilds Smith. Hookers first expedition, led by James Clark Ross, consisted of two ships, HMS Erebus and HMS Terror, it was the last major voyage of exploration made entirely under sail, Hooker was the youngest of the 128-man crew. He sailed on the Erebus and was assistant to Robert McCormick, the ships sailed on 30 September 1839. Before journeying to Antarctica they visited Madeira, Tenerife, Santiago and Quail Island in the Cape Verde archipelago, St Paul Rocks, Trinidade east of Brazil, St Helena, and the Cape of Good Hope. Hooker made plant collections at each location and while travelling drew these and specimens of algae, from the Cape they entered the southern ocean. Their first stop was the Crozet Islands where they set down on Possession Island to deliver coffee to sealers and they departed for the Kerguelen Islands where they would spend several days. The expedition spent some time in Hobart, Van Diemens Land, and then moved on to the Auckland Islands and Campbell Island, and onward to Antarctica to locate the South Magnetic Pole. After spending 5 months in the Antarctic they returned to resupply in Hobart, then went on to Sydney, and they left New Zealand to return to Antarctica. They made a landing at Cockburn Island and after leaving the Antarctic, stopped at the Cape, St Helena and Ascension Island. The ships arrived back in England on 4 September 1843, the voyage had been a success for Ross as it was the first to confirm the existence of the southern continent, in 1845, Hooker applied for the Chair of Botany at the University of Edinburgh
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