Plant ecology is a subdiscipline of ecology which studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, the interactions among and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands. A global overview of the Earth's major vegetation types is provided by O. W. Archibold, he recognizes 11 major vegetation types: tropical forests, tropical savannas, arid regions, Mediterranean ecosystems, temperate forest ecosystems, temperate grasslands, coniferous forests, terrestrial wetlands, freshwater ecosystems and coastal/marine systems. This breadth of topics shows the complexity of plant ecology, since it includes plants from floating single-celled algae up to large canopy forming trees. One feature that defines plants is photosynthesis.
Photosynthesis is the process of a chemical reactions to create glucose and oxgyen, vital for plant life. One of the most important aspects of plant ecology is the role plants have played in creating the oxygenated atmosphere of earth, an event that occurred some 2 billion years ago, it can be dated by the deposition of banded iron formations, distinctive sedimentary rocks with large amounts of iron oxide. At the same time, plants began removing carbon dioxide from the atmosphere, thereby initiating the process of controlling Earth's climate. A long term trend of the Earth has been toward increasing oxygen and decreasing carbon dioxide, many other events in the Earth's history, like the first movement of life onto land, are tied to this sequence of events. One of the early classic books on plant ecology was written by J. E. Weaver and F. E. Clements, it talks broadly about plant communities, the importance of forces like competition and processes like succession. Plant ecology can be divided by levels of organization including plant ecophysiology, plant population ecology, community ecology, ecosystem ecology, landscape ecology and biosphere ecology.
The study of plants and vegetation is complicated by their form. First, most plants are rooted in the soil, which makes it difficult to observe and measure nutrient uptake and species interactions. Second, plants reproduce vegetatively, asexually, in a way that makes it difficult to distinguish individual plants. Indeed, the concept of an individual is doubtful, since a tree may be regarded as a large collection of linked meristems. Hence, plant ecology and animal ecology have different styles of approach to problems that involve processes like reproduction and mutualism; some plant ecologists have placed considerable emphasis upon trying to treat plant populations as if they were animal populations, focusing on population ecology. Many other ecologists believe that while it is useful to draw upon population ecology to solve certain scientific problems, plants demand that ecologists work with multiple perspectives, appropriate to the problem, the scale and the situation. Plant ecology has its origin in the application of plant physiology to the questions raised by plant geographers.
Carl Ludwig Willdenow was one of the first to note that similar climates produced similar types of vegetation when they were located in different parts of the world. Willdenow's student, Alexander von Humboldt, used physiognomy to describe vegetation types and observed that the distribution vegetation types was based on environmental factors. Plant geographers who built upon Humboldt's work included Joakim Frederik Schouw, A. P. de Candolle, August Grisebach and Anton Kerner von Marilaun. Schouw's work, published in 1822, linked plant distributions to environmental factors and established the practice of naming plant associations by adding the suffix -etum to the name of the dominant species. Working from herbarium collections, De Candolle searched for general rules of plant distribution and settled on using temperature as well. Grisebach's two-volume work, Die Vegetation der Erde nach Ihrer Klimatischen Anordnung, published in 1872, saw plant geography reach its "ultimate form" as a descriptive field.
Starting in the 1870s, Swiss botanist Simon Schwendener, together with his students and colleagues, established the link between plant morphology and physiological adaptations, laying the groundwork for the first ecology textbooks, Eugenius Warming's Plantesamfund and Andreas Schimper's 1898 Pflanzengeographie auf Physiologischer Grundlage. Warming incorporated plant morphology, physiology taxonomy and biogeography into plant geography to create the field of plant ecology. Although more morphological than physiological, Schimper's has been considered the beginning of plant physiological ecology. Plant ecology was built around static ideas of plant distribution. Henry Chandler Cowles' studies of plant succession on the Lake Michigan sand dunes and Frederic Clements' 1916 monograph on the subject established it as a key element of plant ecology. Plant ecology developed within the wider discipline of ecology over the twentieth century. Inspired by Warming's Plantesamfund, Arthur Tansley set out to map British plant communities.
In 1904 he teamed up with William Gardner Smith and others involved in vegetation mapping to establish the Central Committee for the Survey and Study of British Vegetation shortened to British Vegetation Committee. In 1913, the British Vegetation Committee organised the British Ecological
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
Bryology is the branch of botany concerned with the scientific study of bryophytes. Bryologists are people who have an active interest in observing, classifying or researching bryophytes; the field is studied along with lichenology due to the similar appearance and ecological niche of the two organisms though bryophytes and lichens are not classified in the same kingdom. Bryophytes were first studied in detail in the 18th century; the German botanist Johann Jacob Dillenius was a professor at Oxford and in 1717 produced the work "Reproduction of the ferns and mosses." The beginning of bryology belongs to the work of Johannes Hedwig, who clarified the reproductive system of mosses and arranged a taxonomy. Areas of research include bryophyte taxonomy, bryophytes as bioindicators, DNA sequencing, the interdependency of bryophytes and other plant and animal species. Among other things, scientists have discovered parasitic bryophytes such as Cryptothallus and carnivorous liverworts such as Colura zoophaga and Pleurozia.
Centers of research in bryology include the University of Bonn in Germany, the University of Helsinki in Finland and the New York Botanical Garden. Miles Joseph Berkeley Elizabeth Gertrude Britton Margaret Sibella Brown Heinrich Christian Funck Robert Kaye Greville Wilhelm Theodor Gümbel Inez M. Haring Hiroshi Inoue Mary S. Taylor Carl Friedrich Warnstorf Meylania, Zeitschrift für Bryologie und Lichenologie Limprichtia, Zeitschrift der Bryologischen Arbeitsgemeinschaft Deutschlands Bryologie at the University of Bonn A Short History of Bryology International Association of Bryologists American Bryological and Lichenological Society British Bryological Society
The term cultivar most refers to an assemblage of plants selected for desirable characters that are maintained during propagation. More cultivar refers to the most basic classification category of cultivated plants in the International Code of Nomenclature for Cultivated Plants. Most cultivars arose in cultivation. Popular ornamental garden plants like roses, daffodils and azaleas are cultivars produced by careful breeding and selection for floral colour and form; the world's agricultural food crops are exclusively cultivars that have been selected for characters such as improved yield and resistance to disease, few wild plants are now used as food sources. Trees used in forestry are special selections grown for their enhanced quality and yield of timber. Cultivars form a major part of Liberty Hyde Bailey's broader group, the cultigen, defined as a plant whose origin or selection is due to intentional human activity. A cultivar is not the same as a botanical variety, a taxonomic rank below subspecies, there are differences in the rules for creating and using the names of botanical varieties and cultivars.
In recent times, the naming of cultivars has been complicated by the use of statutory patents for plants and recognition of plant breeders' rights. The International Union for the Protection of New Varieties of Plants offers legal protection of plant cultivars to persons or organisations that introduce new cultivars to commerce. UPOV requires that a cultivar be "distinct, uniform", "stable". To be "distinct", it must have characters that distinguish it from any other known cultivar. To be "uniform" and "stable", the cultivar must retain these characters in repeated propagation; the naming of cultivars is an important aspect of cultivated plant taxonomy, the correct naming of a cultivar is prescribed by the Rules and Recommendations of the International Code of Nomenclature for Cultivated Plants. A cultivar is given a cultivar name, which consists of the scientific Latin botanical name followed by a cultivar epithet; the cultivar epithet is in a vernacular language. For example, the full cultivar name of the King Edward potato is Solanum tuberosum'King Edward'.'King Edward' is the cultivar epithet, according to the Rules of the Cultivated Plant Code, is bounded by single quotation marks.
The word cultivar originated from the need to distinguish between wild plants and those with characteristics that arose in cultivation, presently denominated cultigens. This distinction dates to the Greek philosopher Theophrastus, the "Father of Botany", keenly aware of this difference. Botanical historian Alan Morton noted that Theophrastus in his Historia Plantarum "had an inkling of the limits of culturally induced changes and of the importance of genetic constitution"; the International Code of Nomenclature for algae and plants uses as its starting point for modern botanical nomenclature the Latin names in Linnaeus' Species Plantarum and Genera Plantarum. In Species Plantarum, Linnaeus enumerated all plants known to him, either directly or from his extensive reading, he recognised the rank of varietas and he indicated these varieties with letters of the Greek alphabet, such as α, β, λ, before the varietal name, rather than using the abbreviation "var." as is the present convention. Most of the varieties that Linnaeus enumerated were of "garden" origin rather than being wild plants.
In time the need to distinguish between wild plants and those with variations, cultivated increased. In the nineteenth century many "garden-derived" plants were given horticultural names, sometimes in Latin and sometimes in a vernacular language. From circa the 1900s, cultivated plants in Europe were recognised in the Scandinavian and Slavic literature as stamm or sorte, but these words could not be used internationally because, by international agreement, any new denominations had to be in Latin. In the twentieth century an improved international nomenclature was proposed for cultivated plants. Liberty Hyde Bailey of Cornell University in New York, United States created the word cultivar in 1923 when he wrote that: The cultigen is a species, or its equivalent, that has appeared under domestication – the plant is cultigenous. I now propose another name, for a botanical variety, or for a race subordinate to species, that has originated under cultivation, it is the equivalent of the botanical variety except in respect to its origin.
In that essay, Bailey used only the rank of species for the cultigen, but it was obvious to him that many domesticated plants were more like botanical varieties than species, that realization appears to have motivated the suggestion of the new category of cultivar. Bailey created the word cultivar, assumed to be a portmanteau of cultivated and variety. Bailey never explicitly stated the etymology of cultivar, it has been suggested that it is instead a contraction of cultigen and variety, which seems correct; the neologism cultivar was promoted as "euphonious" and "free from ambiguity". The first Cultivated Plant Code of 1953 subsequently commended its use, by 1960 it had achieved common international acceptance; the words cultigen and cultivar may be confused with
International Code of Nomenclature for algae, fungi, and plants
The International Code of Nomenclature for algae and plants is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "traditionally treated as algae, fungi, or plants". It was called the International Code of Botanical Nomenclature; the current version of the code is the Shenzhen Code adopted by the International Botanical Congress held in Shenzhen, China, in July 2017. As with previous codes, it took effect as soon as it was ratified by the congress, but the documentation of the code in its final form was not published until 26 June 2018; the name of the Code is capitalized and not. The lower-case for "algae and plants" indicates that these terms are not formal names of clades, but indicate groups of organisms that were known by these names and traditionally studied by phycologists and botanists; this includes blue-green algae. There are special provisions in the ICN for some of these groups.
The ICN can only be changed by an International Botanical Congress, with the International Association for Plant Taxonomy providing the supporting infrastructure. Each new edition supersedes the earlier editions and is retroactive back to 1753, except where different starting dates are specified. For the naming of cultivated plants there is a separate code, the International Code of Nomenclature for Cultivated Plants, which gives rules and recommendations that supplement the ICN. Botanical nomenclature is independent of zoological and viral nomenclature. A botanical name is fixed to a taxon by a type; this is invariably dried plant material and is deposited and preserved in a herbarium, although it may be an image or a preserved culture. Some type collections can be viewed online at the websites of the herbaria in question. A guiding principle in botanical nomenclature is priority, the first publication of a name for a taxon; the formal starting date for purposes of priority is 1 May 1753, the publication of Species Plantarum by Linnaeus.
However, to avoid undesirable effects of strict enforcement of priority, conservation of family and species names is possible. The intent of the Code is that each taxonomic group of plants has only one correct name, accepted worldwide, provided that it has the same circumscription and rank; the value of a scientific name is. Names of taxa are treated as Latin; the rules of nomenclature are retroactive unless there is an explicit statement that this does not apply. The rules governing botanical nomenclature have a long and tumultuous history, dating back to dissatisfaction with rules that were established in 1843 to govern zoological nomenclature; the first set of international rules was the Lois de la nomenclature botanique, adopted as the "best guide to follow for botanical nomenclature" at an "International Botanical Congress" convened in Paris in 1867. Unlike modern codes, it was not enforced, it was organized as six sections with 68 articles in total. Multiple attempts to bring more "expedient" or more equitable practice to botanical nomenclature resulted in several competing codes, which reached a compromise with the 1930 congress.
In the meantime, the second edition of the international rules followed the Vienna congress in 1905. These rules were published as the Règles internationales de la Nomenclature botanique adoptées par le Congrès International de Botanique de Vienne 1905. Informally they are referred to as the Vienna Rules; some but not all subsequent meetings of the International Botanical Congress have produced revised versions of these Rules called the International Code of Botanical Nomenclature, International Code of Nomenclature for algae and plants. The Nomenclature Section of the 18th International Botanical Congress in Melbourne, Australia made major changes: The Code now permits electronic-only publication of names of new taxa; the requirement for a Latin validating diagnosis or description was changed to allow either English or Latin for these essential components of the publication of a new name. "One fungus, one name" and "one fossil, one name" are important changes. As an experiment with "registration of names", new fungal descriptions require the use of an identifier from "a recognized repository".
Some important versions are listed below. Specific to botany Author citation Botanical name Botanical nomenclature International Association for Plant Taxonomy International Code of Nomenclature for Cultivated Plants International Plant Names Index Correct name Infraspecific name Hybrid name More general Glossary of scientific naming Binomial nomenclature Nomenclature codes Scientific classification Undescribed species
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents, but can show hybrid vigour, sometimes growing larger or taller than either parent; the concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how related the parent species are. Species are reproductively isolated by strong barriers to hybridisation, which include morphological differences, differing times of fertility, mating behaviors and cues, physiological rejection of sperm cells or the developing embryo; some act before fertilization and others after it. Similar barriers exist in plants, with differences in flowering times, pollen vectors, inhibition of pollen tube growth, somatoplastic sterility, cytoplasmic-genic male sterility and the structure of the chromosomes.
A few animal species and many plant species, are the result of hybrid speciation, including important crop plants such as wheat, where the number of chromosomes has been doubled. Human impact on the environment has resulted in an increase in the interbreeding between regional species, the proliferation of introduced species worldwide has resulted in an increase in hybridisation; this genetic mixing may threaten many species with extinction, while genetic erosion in crop plants may be damaging the gene pools of many species for future breeding. A form of intentional human-mediated hybridisation is the crossing of wild and domesticated species; this is common in modern agriculture. One such flower, Oenothera lamarckiana, was central to early genetics research into mutationism and polyploidy, it is more done in the livestock and pet trades. Human selective breeding of domesticated animals and plants has resulted is the development of distinct breeds. Hybrid humans existed in prehistory. For example and anatomically modern humans are thought to have interbred as as 40,000 years ago.
Mythological hybrids appear in human culture in forms as diverse as the Minotaur, blends of animals and mythical beasts such as centaurs and sphinxes, the Nephilim of the Biblical apocrypha described as the wicked sons of fallen angels and attractive women. The term hybrid is derived from Latin hybrida, used for crosses such as of a tame sow and a wild boar; the term came into popular use in English in the 19th century, though examples of its use have been found from the early 17th century. Conspicuous hybrids are popularly named with portmanteau words, starting in the 1920s with the breeding of tiger–lion hybrids. From the point of view of animal and plant breeders, there are several kinds of hybrid formed from crosses within a species, such as between different breeds. Single cross hybrids result from the cross between two true-breeding organisms which produces an F1 hybrid; the cross between two different homozygous lines produces an F1 hybrid, heterozygous. The F1 generation is phenotypically homogeneous, producing offspring that are all similar to each other.
Double cross hybrids result from the cross between two different F1 hybrids. Three-way cross hybrids result from the cross between an inbred line. Triple cross hybrids result from the crossing of two different three-way cross hybrids. Top cross hybrids result from the crossing of a top quality or pure-bred male and a lower quality female, intended to improve the quality of the offspring, on average. Population hybrids result from the crossing of plants or animals in one population with those of another population; these crosses between different breeds. In horticulture, the term stable hybrid is used to describe an annual plant that, if grown and bred in a small monoculture free of external pollen produces offspring that are "true to type" with respect to phenotype. Hybridisation can occur in the hybrid zones where the geographical ranges of species, subspecies, or distinct genetic lineages overlap. For example, the butterfly Limenitis arthemis has two major subspecies in North America, L. a. arthemis and L. a. astyanax.
The white admiral has a bright, white band on its wings, while the red-spotted purple has cooler blue-green shades. Hybridisation occurs between a narrow area across New England, southern Ontario, the Great Lakes, the "suture region", it is at these regions. Other hybrid zones have formed between described species of animals. From the point of view of genetics, several different kinds of hybrid can be distinguished. A genetic hybrid carries two different alleles of the same gene, where for instance one allele may code for a lighter coat colour than the other. A structural hybrid results from the fusion of gametes that have differing structure in at least one chromosome, as a result of structural abnormalities. A numerical hybrid results from the fusion of gamet
Cattleya is a genus of orchids from Costa Rica south to Argentina. The genus is abbreviated C in trade journals. Epiphytic or terrestrial orchids with cylindrical rhizome from which the fleshy noodle-like roots grow. Pseudobulbs can be spindle-shaped or cylindrical; the leaves can be lanceolate or elliptical, somewhat fleshy, with smooth margin. The inflorescence is a terminal raceme with several flowers. Flowers have petals free from each other. There are four polliniums; the fruit is a capsule with many small seeds. The genus was named in 1824 by John Lindley after horticulturalist William Cattley. Cattley obtained a specimen of unnamed Cattleya labiata from William Swainson who had discovered the new plant in Pernambuco, Brazil, in 1817; the plant bloomed under the care of Cattley and it became the type specimen from which Lindley described C. labiata. Accepted species and subgeneric division within genus Cattleya are: C. aurea C. dowiana. C. gaskelliana. C. iricolor. C. jenmanii. C. labiata C. luteola.
C. mendelii. C. mooreana. C. mossiae C. percivaliana. C. quadricolor C. rex. C. schroederae. C. trianae. C. warneri. C. warscewiczii. C. crispa C. grandis. C. lobata C. perrinii C. purpurata C. tenebrosa. C. virens C. xanthina. C. alaorii. C. bicalhoi. C. jongheana. C. praestans C. pumila C. sincorana. C. lundii. C. alvarenguensis C. alvaroana. C. angereri. C. blumenscheinii. C. bradei. C. briegeri. C. campacii. C. caulescens. C. cinnabarina. C. colnagoi. C. conceicionensis Brazil - Minas Gerais) C. crispata C. endsfeldzii. C. esalqueana. C. flavasulina C. fournieri C. ghillanyi. C. gloedeniana C. gracilis. C. hatae C. hegeriana C. hispidula. C. hoehnei C. itambana. C. kautskyana. C. kettieana C. kleberi C. liliputana. C. locatellii C. longipes. C. luetzelburgii. C. macrobulbosa C. marcaliana. C. milleri. C. mirandae. C. munchowiana. C. neokautskyi C. pabstii C. pendula C. pfisteri. C. presidentensis. C. reginae. C. rupestris. C. viridiflora C. acuensis. C. alagoensis C. brevipedunculata. C. cernua. C. coccinea. C. dichroma. C. mantiqueirae.
C. pygmaea. C. wittigiana. C. lawrenceana. C. lueddemanniana. C. wallisii C. araguaiensis C. aclandiae C. amethystoglossa C. bicolor C. dormaniana C. elongata C. forbesii C. granulosa C. guttata. C. harrisoniana. C. intermedia. C. kerrii. C. loddigesii. C. nobilior. C. porphyroglossa. C. schilleriana. C. schofieldiana C. tenuis. C. tigrina. C. velutina C. violacea. C. walkeriana. C. maxima. Accepted natural hybrids are: This section is incomplete. Hybrids of Cattleya and other genera are placed in the following nothogenera: Brassocattleya = Brassavola × Cattleya Brassolaeliocattleya = Brassavola × Cattleya × Laelia Cattleytonia = Cattleya × Broughtonia Rhyncholaeliocattleya = Rhyncholaelia × Cattleya LightCattleyas need light, but not direct sunlight. TemperatureDay temperatures must be between 25-30 °C and night temperatures not lower than 10-12 °C. HumidityMust be between 40-70% with good ventilation. WateringWater only if substrate is dry, it can be done once a week. FertilizingCattleyas can survive without fertilizing.
However, it is advisable to use nitrogen-base