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
In botany, a drupe is an indehiscent fruit in which an outer fleshy part surrounds a single shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, from flowers with superior ovaries; the definitive characteristic of a drupe is that the hard, "lignified" stone is derived from the ovary wall of the flower—in an aggregate fruit composed of small, individual drupes, each individual is termed a drupelet and may together form a botanic berry. Other fleshy fruits may have a stony enclosure that comes from the seed coat surrounding the seed, but such fruits are not drupes; some flowering plants that produce drupes are: coffee, mango, most palms, white sapote and all members of the genus Prunus, including the almond, cherry, nectarine and plum. The term drupaceous is applied to a fruit which has the structure and texture of a drupe, but which does not fit the definition of a drupe; the boundary between a drupe and a berry is not always clear. Thus, some sources describe the fruit of species of the genus Persea, which includes the avocado, as a "drupe", others describe avocado fruit as a "berry".
One definition of "berry" requires the endocarp to be less than 2 mm thick, other fruits with a stony endocarp being "drupes". In marginal cases, terms such as "drupaceous" or "drupe-like" may be used; the term stone fruit can be a synonym for drupe or, more it can mean just the fruit of the genus Prunus. Freestone refers to a drupe having a stone with ease; the flesh does not need to be cut to free the stone. Freestone varieties of fruits are preferred for uses that require careful removal of the stone if removal will be done by hand. Freestone plums are preferred for making homegrown prunes, freestone sour cherries are preferred for making pies and cherry soup. Clingstone refers to a drupe having a stone which cannot be removed from the flesh; the flesh is attached to the stone and must be cut to free the stone. Clingstone varieties of fruits in the genus Prunus are preferred as table fruit and for jams, because the flesh of clingstone fruits tends to be more tender and juicy throughout. Tryma is a specialized term for such nut-like drupes.
Hickory nuts and walnuts in the Juglandaceae family grow within an outer husk. Many drupes, with their sweet, fleshy outer layer, attract the attention of animals as a food, the plant population benefits from the resulting dispersal of its seeds; the endocarp is sometimes dropped after the fleshy part is eaten, but is swallowed, passing through the digestive tract, returned to the soil in feces with the seed inside unharmed. This passage through the digestive tract can reduce the thickness of the endocarp, thus can aid in germination rates; the process is known as scarification. Typical drupes include apricots, peaches, cherries and amlas. Other examples include ivy; the coconut is a drupe, but the mesocarp is fibrous or dry, so this type of fruit is classified as a simple dry, fibrous drupe. Unlike other drupes, the coconut seed is unlikely to be dispersed by being swallowed by fauna, due to its large size, it can, float long distances across oceans. Bramble fruits are aggregates of drupelets; the fruit of blackberries and raspberries comes from a single flower whose pistil is made up of a number of free carpels.
However, which resemble blackberries, are not aggregate fruit, but are multiple fruits derived from bunches of catkins, each drupelet thus belonging to a different flower. Certain drupes occur in large clusters, as in the case of palm species, where a sizable array of drupes is found in a cluster. Examples of such large drupe clusters include dates, Jubaea chilensis in central Chile and Washingtonia filifera in the Sonoran Desert of North America. Pome Identification Of Major Fruit Types Fruits Called Nuts "Drupe". New International Encyclopedia. 1905
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants. The biological function of a flower is to effect reproduction by providing a mechanism for the union of sperm with eggs. Flowers may allow selfing; some flowers produce diaspores without fertilization. Flowers are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds. In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to bring beauty to their environment, as objects of romance, religion, medicine and as a source of food; the essential parts of a flower can be considered in two parts: the vegetative part, consisting of petals and associated structures in the perianth, the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk.
Each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls are as follows: Collectively the calyx and corolla form the perianth. Calyx: the outermost whorl consisting of units called sepals. Corolla: the next whorl toward the apex, composed of units called petals, which are thin and colored to attract animals that help the process of pollination. Androecium: the next whorl, consisting of units called stamens. Stamens consist of two parts: a stalk called a filament, topped by an anther where pollen is produced by meiosis and dispersed. Gynoecium: the innermost whorl of a flower, consisting of one or more units called carpels; the carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes; these give rise to egg cells. The gynoecium of a flower is described using an alternative terminology wherein the structure one sees in the innermost whorl is called a pistil.
A pistil may consist of a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen; the supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma. The relationship to the gynoecium on the receptacle is described as hypogynous, perigynous, or epigynous. Although the arrangement described above is considered "typical", plant species show a wide variation in floral structure; these modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. The four main parts of a flower are defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is another part. In some families, like Ranunculaceae, the petals are reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens.
Flowers show great variation and plant scientists describe this variation in a systematic way to identify and distinguish species. Specific terminology is used to describe their parts. Many flower parts are fused together; when petals are fused into a tube or ring that falls away as a single unit, they are sympetalous. Connate petals may have distinctive regions: the cylindrical base is the tube, the expanding region is the throat and the flaring outer region is the limb. A sympetalous flower, with bilateral symmetry with an upper and lower lip, is bilabiate. Flowers with connate petals or sepals may have various shaped corolla or calyx, including campanulate, tubular, salverform or rotate. Referring to "fusion," as it is done, appears questionable because at least some of the processes involved may be non-fusion processes. For example, the addition of intercalary growth at or below the base of the primordia of floral appendages such as sepals, petals and carpels may lead to a common base, not the result of fusion.
Many flowers have a symmetry. When the perianth is bisected through the central axis from any point and symmetrical halves are produced, the flower is said to be actinomorphic or regular, e.g. rose or trillium. This is an example of radial symmetry; when flowers are bisected and produce only one line that produces symmetrical halves, the flower is said to be irregular or zygomorphic, e.g. snapdragon or most orchids. Flowers may be directly attached to the plant at their base; the stem or stalk subtending a flower is called a peduncle. If a peduncle supports more than o
Plant reproductive morphology
Plant reproductive morphology is the study of the physical form and structure of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, which are the reproductive structures of angiosperms, are the most varied physically and show a correspondingly great diversity in methods of reproduction. Plants that are not flowering plants have complex interplays between morphological adaptation and environmental factors in their sexual reproduction; the breeding system, or how the sperm from one plant fertilizes the ovum of another, depends on the reproductive morphology, is the single most important determinant of the genetic structure of nonclonal plant populations. Christian Konrad Sprengel studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwin's theories of natural selection utilized this work to build his theory of evolution, which includes analysis of the coevolution of flowers and their insect pollinators.
Plants have complex lifecycles involving alternation of generations. One generation, the sporophyte, gives rise to the next generation asexually via spores. Spores may be identical isospores or come in different sizes, but speaking and sporophytes are neither male nor female because they do not produce gametes; the alternate generation, the gametophyte, sperm. A gametophyte can be monoicous, producing both eggs and sperm or dioicous, either male. In the bryophytes, the sexual gametophyte is the dominant generation. In ferns and seed plants the sporophyte is the dominant generation; the obvious visible plant, whether a small herb or a large tree, is the sporophyte, the gametophyte is small. In seed plants, each female gametophyte, the spore that gives rise to it, is hidden within the sporophyte and is dependent on it for nutrition; each male gametophyte consists of from two to four cells enclosed within the protective wall of a pollen grain. The sporophyte of a flowering plant is described using sexual terms based on the sexuality of the gametophyte it gives rise to.
For example, a sporophyte that produces spores that give rise only to male gametophytes may be described as "male" though the sporophyte itself is asexual, producing only spores. Flowers produced by the sporophyte may be described as "unisexual" or "bisexual", meaning that they give rise to either one sex of gametophyte or both sexes of gametophyte; the flower is the characteristic structure concerned with sexual reproduction in flowering plants. Flowers vary enormously in their construction. A "complete" flower, like that of Ranunculus glaberrimus shown in the figure, has a calyx of outer sepals and a corolla of inner petals; the sepals and petals together form the perianth. Next inwards there are numerous stamens, which produce pollen grains, each containing a microscopic male gametophyte. Stamens may collectively form the androecium. In the middle there are carpels, which at maturity contain one or more ovules, within each ovule is a tiny female gametophyte. Carpels may collectively form the gynoecium.
Each carpel in Ranunculus species is an achene that produces one ovule, which when fertilized becomes a seed. If the carpel contains more than one seed, as in Eranthis hyemalis, it is called a follicle. Two or more carpels may be fused together to varying degrees and the entire structure, including the fused styles and stigmas may be called a pistil; the lower part of the pistil, where the ovules are produced, is called the ovary. It may be divided into chambers corresponding to the separate carpels. A "perfect" flower has both stamens and carpels, may be described as "bisexual" or "hermaphroditic". A "unisexual" flower is one in which either the stamens or the carpels are missing, vestigial or otherwise non-functional; each flower is either "staminate" and thus "male", or "carpellate" and thus "female". If separate staminate and carpellate flowers are always found on the same plant, the species is called monoecious. If separate staminate and carpellate flowers are always found on different plants, the species is called dioecious.
A 1995 study found that about 6% of angiosperm species are dioecious, that 7% of genera contain some dioecious species. Members of the birch family are examples of monoecious plants with unisexual flowers. A mature alder tree produces long catkins containing only male flowers, each with four stamens and a minute perianth, separate stalked groups of female flowers, each without a perianth. Most hollies are dioecious; each plant produces either functionally functionally female flowers. In Ilex aquifolium, the common European holly, both kinds of flower have four sepals and four white petals. Since only female plants are able to set fruit and produce berries, this has consequences for gardeners. Amborella represents the first known group of flowering plants to separate from their common ancestor, it too is dioecio
Romania is a country located at the crossroads of Central and Southeastern Europe. It borders the Black Sea to the southeast, Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, it has a predominantly temperate-continental climate. With a total area of 238,397 square kilometres, Romania is the 12th largest country and the 7th most populous member state of the European Union, having 20 million inhabitants, its capital and largest city is Bucharest, other major urban areas include Cluj-Napoca, Timișoara, Iași, Constanța, Brașov. The River Danube, Europe's second-longest river, rises in Germany's Black Forest and flows in a general southeast direction for 2,857 km, coursing through ten countries before emptying into Romania's Danube Delta; the Carpathian Mountains, which cross Romania from the north to the southwest, include Moldoveanu Peak, at an altitude of 2,544 m. Modern Romania was formed in 1859 through a personal union of the Danubian Principalities of Moldavia and Wallachia.
The new state named Romania since 1866, gained independence from the Ottoman Empire in 1877. Following World War I, when Romania fought on the side of the Allied powers, Bessarabia, Transylvania as well as parts of Banat, Crișana, Maramureș became part of the sovereign Kingdom of Romania. In June–August 1940, as a consequence of the Molotov–Ribbentrop Pact and Second Vienna Award, Romania was compelled to cede Bessarabia and Northern Bukovina to the Soviet Union, Northern Transylvania to Hungary. In November 1940, Romania signed the Tripartite Pact and in June 1941 entered World War II on the Axis side, fighting against the Soviet Union until August 1944, when it joined the Allies and recovered Northern Transylvania. Following the war, under the occupation of the Red Army's forces, Romania became a socialist republic and member of the Warsaw Pact. After the 1989 Revolution, Romania began a transition back towards a market economy; the sovereign state of Romania is a developing country and ranks 52nd in the Human Development Index.
It has the world's 47th largest economy by nominal GDP and an annual economic growth rate of 7%, the highest in the EU at the time. Following rapid economic growth in the early 2000s, Romania has an economy predominantly based on services, is a producer and net exporter of machines and electric energy, featuring companies like Automobile Dacia and OMV Petrom, it has been a member of the United Nations since 1955, part of NATO since 2004, part of the European Union since 2007. An overwhelming majority of the population identifies themselves as Eastern Orthodox Christians and are native speakers of Romanian, a Romance language. Romania derives from the Latin romanus, meaning "citizen of Rome"; the first known use of the appellation was attested to in the 16th century by Italian humanists travelling in Transylvania and Wallachia. The oldest known surviving document written in Romanian, a 1521 letter known as the "Letter of Neacșu from Câmpulung", is notable for including the first documented occurrence of the country's name: Wallachia is mentioned as Țeara Rumânească.
Two spelling forms: român and rumân were used interchangeably until sociolinguistic developments in the late 17th century led to semantic differentiation of the two forms: rumân came to mean "bondsman", while român retained the original ethnolinguistic meaning. After the abolition of serfdom in 1746, the word rumân fell out of use and the spelling stabilised to the form român. Tudor Vladimirescu, a revolutionary leader of the early 19th century, used the term Rumânia to refer to the principality of Wallachia."The use of the name Romania to refer to the common homeland of all Romanians—its modern-day meaning—was first documented in the early 19th century. The name has been in use since 11 December 1861. In English, the name of the country was spelt Rumania or Roumania. Romania became the predominant spelling around 1975. Romania is the official English-language spelling used by the Romanian government. A handful of other languages have switched to "o" like English, but most languages continue to prefer forms with u, e.g. French Roumanie and Swedish Rumänien, Spanish Rumania, Polish Rumunia, Russian Румыния, Japanese ルーマニア.
1859–1862: United Principalities of Moldavia and Wallachia 1862–1866: Romanian United Principalities or Romania 1866–1881: Romania or Principality of Romania 1881–1947: Kingdom of Romania or Romania 1947–1965: Romanian People's Republic or Romania 1965–December, 1989: Socialist Republic of Romania or Romania December, 1989–present: Romania Human remains found in Peștera cu Oase, radiocarbon dated as being from circa 40,000 years ago, represent the oldest known Homo sapiens in Europe. Neolithic techniques and agriculture spread after the arrival of a mixed group of people from Thessaly in the 6th millenium BC. Excavations near a salt spring at Lunca yielded the earliest evidence for salt exploitation in Europe; the first permanent settlements appeared in the Neolithic. Some of them developed into "proto-cities"; the Cucuteni–Trypillia culture—the best known archaeological culture of Old Europe—flourished in Muntenia, southeastern Transylvania and northeastern Moldavia in the 3rd m
In scientific nomenclature, a synonym is a scientific name that applies to a taxon that goes by a different scientific name, although the term is used somewhat differently in the zoological code of nomenclature. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies; this name is no longer in use: it is now a synonym of the current scientific name, Picea abies. Unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms have a different status. For any taxon with a particular circumscription and rank, only one scientific name is considered to be the correct one at any given time. A synonym cannot exist in isolation: it is always an alternative to a different scientific name. Given that the correct name of a taxon depends on the taxonomic viewpoint used a name, one taxonomist's synonym may be another taxonomist's correct name. Synonyms may arise whenever the same taxon is named more than once, independently.
They may arise when existing taxa are changed, as when two taxa are joined to become one, a species is moved to a different genus, a variety is moved to a different species, etc. Synonyms come about when the codes of nomenclature change, so that older names are no longer acceptable. To the general user of scientific names, in fields such as agriculture, ecology, general science, etc. A synonym is a name, used as the correct scientific name but, displaced by another scientific name, now regarded as correct, thus Oxford Dictionaries Online defines the term as "a taxonomic name which has the same application as another one, superseded and is no longer valid." In handbooks and general texts, it is useful to have synonyms mentioned as such after the current scientific name, so as to avoid confusion. For example, if the much advertised name change should go through and the scientific name of the fruit fly were changed to Sophophora melanogaster, it would be helpful if any mention of this name was accompanied by "".
Synonyms used in this way may not always meet the strict definitions of the term "synonym" in the formal rules of nomenclature which govern scientific names. Changes of scientific name have two causes: they may be taxonomic or nomenclatural. A name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight. A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature. Speaking in general, name changes for nomenclatural reasons have become less frequent over time as the rules of nomenclature allow for names to be conserved, so as to promote stability of scientific names. In zoological nomenclature, codified in the International Code of Zoological Nomenclature, synonyms are different scientific names of the same taxonomic rank that pertain to that same taxon. For example, a particular species could, over time, have had two or more species-rank names published for it, while the same is applicable at higher ranks such as genera, orders, etc.
In each case, the earliest published name is called the senior synonym, while the name is the junior synonym. In the case where two names for the same taxon have been published the valid name is selected accorded to the principle of the first reviser such that, for example, of the names Strix scandiaca and Strix noctua, both published by Linnaeus in the same work at the same date for the taxon now determined to be the snowy owl, the epithet scandiaca has been selected as the valid name, with noctua becoming the junior synonym. One basic principle of zoological nomenclature is that the earliest published name, the senior synonym, by default takes precedence in naming rights and therefore, unless other restrictions interfere, must be used for the taxon. However, junior synonyms are still important to document, because if the earliest name cannot be used the next available junior synonym must be used for the taxon. For other purposes, if a researcher is interested in consulting or compiling all known information regarding a taxon, some of this may well have been published under names now regarded as outdated and so it is again useful to know a list of historic synonyms which may have been used for a given current taxon name.
Objective synonyms refer to taxa with same rank. This may be species-group taxa of the same rank with the same type specimen, genus-group taxa of the same rank with the same type species or if their type species are themselves objective synonyms, of family-group taxa with the same type genus, etc. In the case of subjective synonyms, there is no such shared type, so the synonymy is open to taxonomic judgement, meaning that th
Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton and durian. There are some genera containing familiar ornamentals, such as Alcea and Lavatera, as well as Tilia; the largest genera in terms of number of species include Hibiscus, Dombeya and Sida. The circumscription of the Malvaceae is controversial; the traditional Malvaceae sensu stricto comprise a homogeneous and cladistically monophyletic group. Another major circumscription, Malvaceae sensu lato, has been more defined on the basis that molecular techniques have shown the recognised families Bombacaceae and Sterculiaceae, which have always been considered allied to Malvaceae s.s. are not monophyletic groups. Thus, the Malvaceae can be expanded to include all of these families so as to compose a monophyletic group. Adopting this circumscription, the Malvaceae incorporate a much larger number of genera; this article is based on the second circumscription, as presented by the Angiosperm Phylogeny Website.
The Malvaceae s.l. comprise nine subfamilies. A tentative cladogram of the family is shown below; the diamond denotes a poorly supported branching. It is important to point out the relationships between these subfamilies are still either poorly supported or completely obscure. There are continuing disagreements over the correct circumscription of these subfamilies, including the preservation of the family, Bombacaceae; the circumscription of the family may change as new studies are published. If looking for information about the traditional Malvaceae s.s. we recommend referring to Malvoideae, the subfamily that corresponds to that group. The relationships between the "core Malvales" families used to be defined on the basis of shared "malvean affinities." These included the presence of malvoid teeth, stems with mucilage canals, stratified wedge-shaped phloem. These affinities were problematic. Studies revealed more unambiguous synapomorphies within Malvaceae s.l.. Synapomorphies identified within Malvaceae s.l. include the presence of tile cells, trichomatous nectaries, an inflorescence structure called a bicolor unit.
Tile cells consist of vertically positioned cells interspersed between and dimensionally similar to procumbent ray cells. Evidence of Malvean wood fossils have confirmed their evolutionary link in Malvaceae s.l. as well explained their diverse structures. Flowers of Malvaceae s.l. exhibit nectaries consisting of densely arranged multicellular hairs resembling trichomes. In most of Malvaceae s.l. these trichomatous nectaries are located on the inner surface of the sepals, but flowers of the subfamily, Tiliodeae have present nectaries on the petals. Malvean flowers share a unifying structure known as a bicolor unit, named for its initial discovery in the flowers of Theobroma bicolor; the bicolor unit consists of an ordered inflorescence with determinate cymose structures. The inflorescence can branch off the main axis, creating separate orders of the flowers, with the main axis developing first. Bracts on the peduncle subtend axillary buds. One bract within this whorl is a sterile bract; the bicolor unit is a variable structure in complexity, but the presence of fertile and sterile bracts is a salient character.
The English common name'mallow' comes from Latin malva. Malva itself was derived from the word for the plant in ancient Mediterranean languages. Cognates of the word include Ancient Greek μαλάχη or μολόχη, Modern Greek μολόχα, modern Arabic: ملوخية and modern Hebrew: מלוחיה. Most species are herbs or shrubs. Leaves are alternate palmately lobed or compound and palmately veined; the margin may be entire. Stipules are present; the stems contain mucous canals and also mucous cavities. Hairs are common, are most stellate.. Stems of Bombacoideae are covered in thick prickles; the flowers are borne in definite or indefinite axillary inflorescences, which are reduced to a single flower, but may be cauliflorous, oppositifolious, or terminal. They bear supernumerary bracts in the structure of a bicolor unit, they can be unisexual or bisexual, are actinomorphic associated with conspicuous bracts, forming an epicalyx. They have five valvate sepals, most basally connate, with five imbricate petals; the stamens are five to numerous, connate at least at their bases, but forming a tube around the pistils.
The pistils are composed of two to many connate carpels. The ovary is superior, with capitate or lobed stigma; the flowers have nectaries made of many packed glandular hairs positioned on the sepals. The fruits are most loculicidal capsules, schizocarps or nuts. Self-pollination is avoided by means of protandry. Most species are entomophilous. Bees from the Emphorini tribe of the Apidae are known to specialize on the plants. A number of species are pests in agriculture, including Abutilon theophrasti and Modiola caroliniana, others that are garden escapes. Cotton, kenaf (Hibiscus ca