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
The perianth is the non-reproductive part of the flower, structure that forms an envelope surrounding the sexual organs, consisting of the calyx and the corolla. The term perianth is derived from the Greek περί, meaning around, άνθος, meaning flower, while perigonium is derived from gonos, meaning seed, i.e. sexual organs. In the mosses and liverworts, the perianth is the sterile tubelike tissue that surrounds the female reproductive structure. In flowering plants, the perianth may be described as being either dichlamydeous/heterochlamydeous in which the calyx and corolla are separate, or homochlamydeous, in which they are indistinguishable; when the perianth is in two whorls, it is described as biseriate. While the calyx may be green, known as sepaloid, it may be brightly coloured, is described as petaloid; when the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.
The corolla and petals have a role in attracting pollinators, but this may be augmented by more specialised structures like the corona. When the corolla consists of separate tepals the term apotepalous is used, or syntepalous if the tepals are fused to one another; the petals may be united to form a tubular corolla. If either the petals or sepals are absent, the perianth can be described as being monochlamydeous. Both sepals and petals may have stomata and veins if vestigial. In some taxa, for instance some magnolias and water lilies the perianth is arranged in a spiral on nodes, rather than whorls. Flowers with spiral perianths tend to be those with undifferentiated perianths. An additional structure in some plants is the corona, a ring or set of appendages of adaxial tissue arising from the corolla or the outer edge of the stamens, it is positioned where the corolla lobes arise from the corolla tube. The pappus of Asteraceae, considered to be a modified calyx, is called a corona if it is shaped like a crown.
Simpson, Michael G.. Plant Systematics. Academic Press. ISBN 0-08-051404-9. Retrieved 12 February 2014; the dictionary definition of perianth at Wiktionary
Ficus is a genus of about 850 species of woody trees, vines and hemiepiphytes in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extending into the semi-warm temperate zone; the common fig is a temperate species native to southwest Asia and the Mediterranean region, cultivated from ancient times for its fruit referred to as figs. The fruit of most other species are edible though they are of only local economic importance or eaten as bushfood. However, they are important food resources for wildlife. Figs are of considerable cultural importance throughout the tropics, both as objects of worship and for their many practical uses. Ficus is a pan-tropical genus of trees and vines occupying a wide variety of ecological niches. Fig species are characterized by their unique inflorescence and distinctive pollination syndrome, which utilizes wasp species belonging to the family Agaonidae for pollination; the specific identification of many of the species can be difficult, but figs as a group are easy to recognize.
Many have aerial roots and a distinctive shape or habit, their fruits distinguish them from other plants. The fig fruit is an enclosed inflorescence, sometimes referred to as a syconium, an urn-like structure lined on the inside with the fig's tiny flowers; the unique fig pollination system, involving tiny specific wasps, known as fig wasps that enter via ostiole these sub-closed inflorescences to both pollinate and lay their own eggs, has been a constant source of inspiration and wonder to biologists. There are three vegetative traits that together are unique to figs. All figs possess some in copious quantities. There are no unambiguous older fossils of Ficus. However, current molecular clock estimates indicate that Ficus is a ancient genus being at least 60 million years old, as old as 80 million years; the main radiation of extant species, may have taken place more between 20 and 40 million years ago. Some better-known species that represent the diversity of the genus include the common fig, a small temperate deciduous tree whose fingered fig leaf is well known in art and iconography.
Moreover, figs with different plant habits have undergone adaptive radiation in different biogeographic regions, leading to high levels of alpha diversity. In the tropics, it is quite common to find that Ficus is the most species-rich plant genus in a particular forest. In Asia as many as 70 or more species can co-exist. Ficus species richness declines with an increase in latitude in both hemispheres. Figs are keystone species in many tropical forest ecosystems, their fruit are a key resource for some frugivores including fruit bats, primates including: capuchin monkeys, langurs and mangabeys. They are more important for birds such as Asian barbets, hornbills, fig-parrots and bulbuls, which may entirely subsist on figs when these are in plenty. Many Lepidoptera caterpillars feed on fig leaves, for example several Euploea species, the plain tiger, the giant swallowtail, the brown awl, Chrysodeixis eriosoma and Copromorphidae moths; the citrus long-horned beetle, for example, has larvae that feed on wood, including that of fig trees.
The sweet potato whitefly is found as a pest on figs grown as potted plants and is spread through the export of these plants to other localities. For a list of other diseases common to fig trees, see List of foliage plant diseases; the wood of fig trees is soft and the latex precludes its use for many purposes. It was used to make mummy caskets in Ancient Egypt. Certain fig species are traditionally used in Mesoamerica to produce papel amate. Mutuba is used to produce barkcloth in Uganda. Pou leaves' shape inspired one of the standard kbach rachana, decorative elements in Cambodian architecture. Indian banyan and the Indian rubber plant, as well as other species, have use in herbalism. Figs have figured prominently in some human cultures. There is evidence that figs the common fig and sycamore fig, were among the first – if not the first – plant species that were deliberately bred for agriculture in the Middle East, starting more than 11,000 years ago. Nine subfossil F. carica figs dated to about 9400–9200 BCE were found in the early Neolithic village Gilgal I.
These were a parthenogenetic type and thus an early cultivar. This find predates the first known cultivation of grain in the Middle East by many hundreds of years; the 1889 book'The Useful Native Plants of Australia’ records that Ficus aspera had the common names "Rough-leaved Fi
Gynoecium is most used as a collective term for the parts of a flower that produce ovules and develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; the gynoecium is referred to as the "female" portion of the flower, although rather than directly producing female gametes, the gynoecium produces megaspores, each of which develops into a female gametophyte which produces egg cells. The term gynoecium is used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses and hornworts; the corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are called carpellate. Flowers lacking a gynoecium are called staminate; the gynoecium is referred to as female because it gives rise to female gametophytes. Gynoecium development and arrangement is important in systematic research and identification of angiosperms, but can be the most challenging of the floral parts to interpret.
The gynoecium may consist of one or more separate pistils. A pistil consists of an expanded basal portion called the ovary, an elongated section called a style and an apical structure that receives pollen called a stigma; the ovary, is the enlarged basal portion which contains placentas, ridges of tissue bearing one or more ovules. The placentas and/or ovule may be born on the gynoecial appendages or less on the floral apex; the chamber in which the ovules develop is called a locule. The style, is a pillar-like stalk; some flowers such as Tulipa do not have a distinct style, the stigma sits directly on the ovary. The style is a hollow tube in some plants such as lilies, or has transmitting tissue through which the pollen tubes grow; the stigma, is found at the tip of the style, the portion of the carpel that receives pollen. It is sticky or feathery to capture pollen; the word "pistil" comes from Latin pistillum meaning pestle. A sterile pistil in a male flower is referred to as a pistillode; the pistils of a flower are considered to be composed of carpels.
A carpel is the female reproductive part of the flower, interpreted as modified leaves bearing structures called ovules, inside which the egg cells form. A pistil may consist of one carpel, with its ovary and stigma, or several carpels may be joined together with a single ovary, the whole unit called a pistil; the gynoecium may consist of one multi-carpellate pistil. The number of carpels is described by terms such as tricarpellate. Carpels are thought to be phylogenetically derived from ovule-bearing leaves or leaf homologues, which evolved to form a closed structure containing the ovules; this structure is rolled and fused along the margin. Although many flowers satisfy the above definition of a carpel, there are flowers that do not have carpels according to this definition because in these flowers the ovule, although enclosed, are borne directly on the shoot apex, only become enclosed by the carpel. Different remedies have been suggested for this problem. An easy remedy that applies to most cases is to redefine the carpel as an appendage that encloses ovule and may or may not bear them.
If a gynoecium has a single carpel, it is called monocarpous. If a gynoecium has multiple, distinct carpels, it is apocarpous. If a gynoecium has multiple carpels "fused" into a single structure, it is syncarpous. A syncarpous gynoecium can sometimes appear much like a monocarpous gynoecium; the degree of connation in a syncarpous gynoecium can vary. The carpels retain separate styles and stigmas; the carpels may be "fused" except for retaining separate stigmas. Sometimes carpels possess distinct ovaries. In a syncarpous gynoecium, the "fused" ovaries of the constituent carpels may be referred to collectively as a single compound ovary, it can be a challenge to determine. If the styles and stigmas are distinct, they can be counted to determine the number of carpels. Within the compound ovary, the carpels may have distinct locules divided by walls called septa. If a syncarpous gynoecium has a single style and stigma and a single locule in the ovary, it may be necessary to examine how the ovules are attached.
Each carpel will have a distinct line of placentation where the ovules are attached. Pistils begin as small primordia on a floral apical meristem, forming than, closer to the apex than sepal and stamen primordia. Morphological and molecular studies of pistil ontogeny reveal that carpels are most homologous to leaves. A carpel has a similar function to a megasporophyll, but includes a stigma, is fused, with ovules enclosed in the enlarged lower portion, the ovary. In some basal angiosperm lineages and Winteraceae, a carpel begins as a shallow cup where the ovules de
A pseudanthium called a flower head or composite flower, is a special type of inflorescence, in which anything from a small cluster to hundreds or sometimes thousands of flowers are grouped together to form a single flower-like structure. Pseudanthia take various forms; the individual flowers of a pseudanthium are called florets. The real flowers are small and greatly reduced, but the pseudanthium itself can sometimes be quite large. Pseudanthia are characteristic of the daisy and sunflower family, whose flowers are differentiated into ray flowers and disk flowers, unique to this family; the disk flowers in the center of the pseudanthium are actinomorphic and the corolla is fused into a tube. Flowers on the periphery are zygomorphic and the corolla has one large lobe. Either ray or disk flowers may be absent in some plants: Senecio vulgaris lacks ray flowers and Taraxacum officinale lacks disk flowers; the pseudanthium has a whorl of bracts below the flowers, forming an involucre. In all cases, a pseudanthium is superficially indistinguishable from a flower, but closer inspection of its anatomy will reveal that it is composed of multiple flowers.
Thus, the pseudanthium represents an evolutionary convergence of the inflorescence to a reduced reproductive unit that may function in pollination like a single flower, at least in plants that are animal pollinated. Head This is an equivalent term for flower pseudanthium when used in the botanical sense. Capitulum Capitulum can be used as an exact synonym for flower head. At least one source defines it as a small flower head. In addition to its botanical use as a term meaning flower head it is used to mean the top of the sphagnum plant. Calathid This is a rarely used term, it was defined in the 1966 book, The genera of flowering plants, as a specific term for a flower head of a plant in the Asteraceae family. However, on-line botanical glossaries do not define it and Google Scholar does not link to any significant usage of the term in a botanical sense. Pseudanthia occur in the following plant families: Apiaceae — pseudanthia are called umbels Araceae — pseudanthia are called spadices Asteraceae Campanulaceae Centrolepidaceae Cornaceae Cyperaceae Dipsacaceae Euphorbiaceae — pseudanthia are called cyathia Eriocaulaceae Hamamelidaceae Moraceae Poaceae Pontederiaceae — in Hydrothrix Proteaceae Rubiaceae Saururaceae — in AnemopsisIn some families it is not yet clear whether the'flower' represents a pseudanthium, because the anatomical work has not been done.
Possible pseudanthia of this type may occur in the following families: Hydatellaceae Lemnaceae Pandanaceae Triuridaceae Phyllanthaceae
The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the Pliocene; some geologists assert that the Neogene cannot be delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes. During this period and birds continued to evolve into modern forms, while other groups of life remained unchanged. Early hominids, the ancestors of humans, appeared in Africa near the end of the period; some continental movement took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the Gulf Stream to transfer heat to the Arctic Ocean; the global climate cooled over the course of the Neogene, culminating in a series of continental glaciations in the Quaternary Period that follows.
In ICS terminology, from upper to lower: The Pliocene Epoch is subdivided into 2 ages: Piacenzian Age, preceded by Zanclean AgeThe Miocene Epoch is subdivided into 6 ages: Messinian Age, preceded by Tortonian Age Serravallian Age Langhian Age Burdigalian Age Aquitanian AgeIn different geophysical regions of the world, other regional names are used for the same or overlapping ages and other timeline subdivisions. The terms Neogene System and upper Tertiary System describe the rocks deposited during the Neogene Period; the continents in the Neogene were close to their current positions. The Isthmus of Panama formed, connecting South America; the Indian subcontinent continued forming the Himalayas. Sea levels fell, creating land bridges between Africa and Eurasia and between Eurasia and North America; the global climate became seasonal and continued an overall drying and cooling trend which began at the start of the Paleogene. The ice caps on both poles began to grow and thicken, by the end of the period the first of a series of glaciations of the current Ice Age began.
Marine and continental flora and fauna have a modern appearance. The reptile group Choristodera became extinct in the early part of the period, while the amphibians known as Allocaudata disappeared at the end. Mammals and birds continued to be the dominant terrestrial vertebrates, took many forms as they adapted to various habitats; the first hominins, the ancestors of humans, may have appeared in southern Europe and migrated into Africa. In response to the cooler, seasonal climate, tropical plant species gave way to deciduous ones and grasslands replaced many forests. Grasses therefore diversified, herbivorous mammals evolved alongside it, creating the many grazing animals of today such as horses and bison. Eucalyptus fossil leaves occur in the Miocene of New Zealand, where the genus is not native today, but have been introduced from Australia; the Neogene traditionally ended at the end of the Pliocene Epoch, just before the older definition of the beginning of the Quaternary Period. However, there was a movement amongst geologists to include ongoing geological time in the Neogene, while others insist the Quaternary to be a separate period of distinctly different record.
The somewhat confusing terminology and disagreement amongst geologists on where to draw what hierarchical boundaries is due to the comparatively fine divisibility of time units as time approaches the present, due to geological preservation that causes the youngest sedimentary geological record to be preserved over a much larger area and to reflect many more environments than the older geological record. By dividing the Cenozoic Era into three periods instead of seven epochs, the periods are more comparable to the duration of periods in the Mesozoic and Paleozoic eras; the International Commission on Stratigraphy once proposed that the Quaternary be considered a sub-era of the Neogene, with a beginning date of 2.58 Ma, namely the start of the Gelasian Stage. In the 2004 proposal of the ICS, the Neogene would have consisted of the Miocene and Pliocene epochs; the International Union for Quaternary Research counterproposed that the Neogene and the Pliocene end at 2.58 Ma, that the Gelasian be transferred to the Pleistocene, the Quaternary be recognized as the third period in the Cenozoic, citing key changes in Earth's climate and biota that occurred 2.58 Ma and its correspondence to the Gauss-Matuyama magnetostratigraphic boundary.
In 2006 ICS and INQUA reached a compromise that made Quaternary a subera, subdividing Cenozoic into the old classical Tertiary and Quaternary, a compromise, rejected by International Union of Geological Sciences because it split both Neogene and Pliocene in two. Following formal discussions at the 2008 International Geological Congress in Oslo, the ICS decided in May 2009 to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.58 Mya and including the Gelasian age, considered part of the Neogene Period and Pliocene Epoch. Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya. "Digital Atlas of Neogene Life for the Southeastern United States". San Jose State University. Archived from the original on 2013-04-23. Retrieved 21 September 2018
Sap is a fluid transported in xylem cells or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from resin, or cell sap. Saps may be broadly divided into two types: xylem sap and phloem sap. Xylem sap consists of a watery solution of hormones, mineral elements and other nutrients. Transport of sap in xylem is characterized by movement from the roots toward the leaves. Over the past century, there has been some controversy regarding the mechanism of xylem sap transport. Xylem sap transport can be disrupted by cavitation—an "abrupt phase change from liquid to vapor"—resulting in air-filled xylem conduits. In addition to being a fundamental physical limit on tree height, two environmental stresses can disrupt xylem transport by cavitation: "increasingly negative xylem pressures associated with water stress, freeze-thaw cycles in temperate climates. Phloem sap consists of sugars and mineral elements dissolved in water, it flows from where carbohydrates are stored to where they are used.
The pressure flow hypothesis proposes a mechanism for phloem sap transport. Although other hypotheses have been proposed. Phloem sap is thought to play a role in sending informational signals throughout vascular plants. "Loading and unloading patterns are determined by the conductivity and number of plasmodesmata and the position-dependent function of solute-specific, plasma membrane transport proteins. Recent evidence indicates that mobile proteins and RNA are part of the plant's long-distance communication signaling system. Evidence exists for the directed transport and sorting of macromolecules as they pass through plasmodesmata." A large number of insects of the order Hemiptera, feed directly on phloem sap, make it the primary component of their diet. Phloem sap is "nutrient-rich compared with many other plant products and lacking in toxins and feeding deterrents, it is consumed as the dominant or sole diet by a restricted range of animals"; this apparent paradox is explained by the fact that phloem sap is physiologically extreme in terms of animal digestion, it is hypothesized that few animals take direct advantage of this because they lack two adaptations that are necessary to enable direct use by animals.
These include the existence of a high ratio of non-essential/essential amino acids in phloem sap for which these adapted Hemiptera insects contain symbiotic microorganisms which can provide them with essential amino acids. A much larger set of animals do however consume phloem sap by proxy, either "through feeding on the honeydew of phloem-feeding hemipterans. Honeydew is physiologically less extreme than phloem sap, with a higher essential:non-essential amino acid ratio and lower osmotic pressure," or by feeding on the biomass of insects that have grown on more direct ingestion of phloem sap. Maple syrup is made from reduced sugar maple xylem sap; the sap is harvested from the Sugar Maple, Acer saccharum. In some countries harvesting the early spring sap of birch trees for human consumption is common practice. Certain palm tree sap can be used to make palm syrup. In the Canary Islands they use the Canary Island Date Palm while in Chile they use the Chilean Wine Palm to make their syrup called miel de palma.