1.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
2.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
3.
Flowering plant
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The flowering plants, also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 416 families, approx. 13,164 known genera and a total of c.295,383 known species, etymologically, angiosperm means a plant that produces seeds within an enclosure, in other words, a fruiting plant. The term angiosperm comes from the Greek composite word meaning enclosed seeds, the ancestors of flowering plants diverged from gymnosperms in the Triassic Period, during the range 245 to 202 million years ago, and the first flowering plants are known from 160 mya. They diversified extensively during the Lower Cretaceous, became widespread by 120 mya, angiosperms differ from other seed plants in several ways, described in the table. These distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants, the amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms. The vascular bundles of the stem are arranged such that the xylem and phloem form concentric rings, in the dicotyledons, the bundles in the very young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium, the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Among the monocotyledons, the bundles are more numerous in the stem and are scattered through the ground tissue. They contain no cambium and once formed the stem increases in diameter only in exceptional cases, the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, and provide the most trustworthy external characteristics for establishing relationships among angiosperm species, the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally on a shoot or from the axil of a leaf, occasionally, as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. There are two kinds of cells produced by flowers. Microspores, which divide to become pollen grains, are the male cells and are borne in the stamens. The female cells called megaspores, which divide to become the egg cell, are contained in the ovule. The flower may consist only of parts, as in willow. Usually, other structures are present and serve to protect the sporophylls, the individual members of these surrounding structures are known as sepals and petals. The outer series is usually green and leaf-like, and functions to protect the rest of the flower, the inner series is, in general, white or brightly colored, and is more delicate in structure. It functions to attract insect or bird pollinators, attraction is effected by color, scent, and nectar, which may be secreted in some part of the flower
4.
Caryophyllales
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Caryophyllales is an order of flowering plants that includes the cacti, carnations, amaranths, ice plants, beets, and many carnivorous plants. Many members are succulent, having fleshy stems or leaves, the members of Caryophyllales include about 6% of eudicot species. This order is part of the core eudicots, currently, the Caryophyllales contains 33 families,692 genera and 11,155 species. As with all taxa, the circumscription of Caryophyllales has changed within various classification systems, all systems recognize a core of families with centrospermous ovules and seeds. More recent treatments have expanded the Caryophyllales to include many carnivorous plants, although the monophyly of the order has been strongly supported, their placement is still uncertain. Systematists are undecided on whether Caryophyllales should be placed within the complex or sister to the asterid clade. This primitive flower might well be found in stock as Wernham, Bessy. Caryophyllales is separated into two suborders, Caryophyllineae and Polygonineae and these two suborders were formerly recognized as two orders, Polygonales and Caryophyllales. As circumscribed by the APG III system, this includes the same families as the APG II system plus the new families, Limeaceae, Lophiocarpaceae, Montiaceae, Talinaceae. Kewaceae, Limeaceae, Macarthuriaceae, Microteaceae, and Petiveriaceae were added in APG IV, recent molecular and biochemical evidence has resolved additional well-supported clades within the Caryophyllales. The APG favours much larger orders and families, and the order Caryophyllales sensu APG should rather be compared to subclass Caryophyllidae sensu Cronquist, a part of the difference lies with what families are recognized. The plants in the Stegnospermataceae and Barbeuiaceae were included in Cronquists Phytolaccaceae, the Chenopodiaceae are included in Amaranthaceae by APG. New to the order are the Asteropeiaceae and Physenaceae, each containing a single genus, earlier systems, such as the Wettstein system, last edition in 1935, and the Engler system, updated in 1964, had a similar order under the name Centrospermae. Tree of Life Characteristics and Phylogenetic Relationships
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Amaranthaceae
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Amaranthaceae is a family of flowering plants known as the amaranth family. It now includes the former goosefoot family Chenopodiaceae, and contains about 165 genera and 2,040 species, making it the most species-rich lineage within the flowering plant order of Caryophyllales. Most of these species are annual or perennial herbs or subshrubs, some are shrubs, many species have stems with thickened nodes. The wood of the stem has a typical anomalous secondary growth. The leaves are alternate, sometimes opposite. The simple leaves are flat or terete, their shape is extremely variable, in some species, the leaves are reduced to minute scales. In most cases, neither basal or terminal aggregations of leaves occur, the flowers are solitary or aggregated in cymes, spikes, or panicles and typically perfect and actinomorphic. Bracts and bracteoles are either herbaceous or scarious, flowers are regular with a herbaceous or scarious perianth of mostly five tepals, often joined. One to five stamens are opposite to tepals or alternating, inserting from a hypogynous disc, the anthers have two or four pollen sacs. In tribe Caroxyloneae, antheres have vesicular appendages, the pollen grains are spherical with many pores, with pore numbers from a few to 250. One to three carpels are fused to a superior ovary with one basal ovule, the diaspores are seeds or fruits, more often the perianth persists and is modified in fruit for means of dispersal. Sometimes even bracts and bracteoles may belong to the diaspore, more rarely the fruit is a circumscissile capsule or a berry. The horizontal or vertical seed often has a thickened or woody seed coat, the green or white embryo is either spirally or annular. The basic chromosome number is mostly 8-9, widespread in the Amaranthaceae is the occurrence of betalain pigments. The former Chenopodiaceae often contain isoflavonoids, in phytochemical research, several methylenedioxyflavonols, saponins, triterpenoids, ecdysteroids, and specific root-located carbohydrates have been found. With around 800 species that are C4-plants, the Amaranthaceae represent the largest group with this photosynthesis pathway among the eudicots, within the family, several types of C4-photosynthesis occur, and about 17 different types of leaf anatomy are realized. Therefore, this photosynthesis pathway seems to have developed about 15 times independently during the evolution of the family. About two-thirds of the C4-species belong to the former Chenopodiaceae, the first occurrence of C4-photosynthesis dates from the early miocene, about 24 million years ago, but in some groups, this photosynthesis pathway has evolved much later, about 6 million years ago
6.
Carl Linnaeus
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Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands and he then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist. Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is also considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
7.
Central Asia
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Central Asia stretches from the Caspian Sea in the west to China in the east and from Afghanistan in the south to Russia in the north. It is also referred to as the -stans as the five countries generally considered to be within the region all have names ending with the Persian suffix -stan. Central Asias five former Soviet republics are Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Central Asia has historically been closely tied to its nomadic peoples and the Silk Road. It has acted as a crossroads for the movement of people, goods, the Silk Road connected Muslim lands with the people of Europe, India, and China. This crossroads position has intensified the conflict between tribalism and traditionalism and modernization, in pre-Islamic and early Islamic times, Central Asia was predominantly Iranian, peopled by Eastern Iranian-speaking Bactrians, Sogdians and Chorasmians and the semi-nomadic Scythians and Parthians. Central Asia is sometimes referred to as Turkestan, the idea of Central Asia as a distinct region of the world was introduced in 1843 by the geographer Alexander von Humboldt. The borders of Central Asia are subject to multiple definitions, historically built political geography and geoculture are two significant parameters widely used in the scholarly literature about the definitions of the Central Asia. The most limited definition was the one of the Soviet Union. This definition was also used outside the USSR during this period. However, the Russian culture has two terms, Средняя Азия and Центральная Азия. Since then, this has become the most common definition of Central Asia, the UNESCO general history of Central Asia, written just before the collapse of the USSR, defines the region based on climate and uses far larger borders. An alternative method is to define the region based on ethnicity and these areas include Xinjiang Uyghur Autonomous Region, the Turkic regions of southern Siberia, the five republics, and Afghan Turkestan. Afghanistan as a whole, the northern and western areas of Pakistan, the Tibetans and Ladakhi are also included. Insofar, most of the peoples are considered the indigenous peoples of the vast region. Central Asia is a large region of varied geography, including high passes and mountains, vast deserts. The vast steppe areas of Central Asia are considered together with the steppes of Eastern Europe as a geographical zone known as the Eurasian Steppe. Much of the land of Central Asia is too dry or too rugged for farming, the Gobi desert extends from the foot of the Pamirs, 77° E, to the Great Khingan Mountains, 116°–118° E. Central Asia has the following geographic extremes, The worlds northernmost desert, at Buurug Deliin Els, Mongolia, the Northern Hemispheres southernmost permafrost, at Erdenetsogt sum, Mongolia, 46°17′ N
8.
Leaf vegetable
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Leaf vegetables, also called potherbs, greens, vegetable greens, leafy greens, or salad greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Although they come from a wide variety of plants, most share a great deal with other leaf vegetables in nutrition. Nearly one thousand species of plants with leaves are known. Leaf vegetables most often come from short-lived herbaceous plants such as lettuce, woody plants whose leaves can be eaten as leaf vegetables include Adansonia, Aralia, Moringa, Morus, and Toona species. The leaves of many crops are also edible for humans. Examples include alfalfa, clover, and most grasses, including wheat and these plants are often much more prolific than more traditional leaf vegetables, but exploitation of their rich nutrition is difficult, primarily because of their high fiber content. This obstacle can be overcome by further processing such as drying and grinding into powder or pulping and pressing for juice, Leaf vegetables contain many typical plant nutrients, but since they are photosynthetic tissues, their vitamin K levels are particularly notable. Phylloquinone, the most common form of the vitamin, is involved in photosynthesis. This causes leaf vegetables to be the primary food class that interacts significantly with the anticoagulant warfarin, Leaf vegetables are typically low in calories and fat, and high in protein per calorie, dietary fiber, vitamin C, pro-vitamin A carotenoids, folate, manganese and vitamin K. The vitamin K content of leaf vegetables is particularly high, since these are photosynthetic tissues, accordingly, users of vitamin K antagonist medications, such as warfarin, must take special care to limit consumption of leaf vegetables. If leaves are cooked for food, they may be referred to as boiled greens, Leaf vegetables may be stir-fried, stewed, steamed, or consumed raw. Leaf vegetables stewed with pork are a dish in soul food. They are also eaten in a variety of South Asian dishes such as saag. Leafy greens can be used to other ingredients into an edible package similar to how a tortilla is used. Many green leafy vegetables, such as lettuce or spinach, can also be eaten raw, a green smoothie enables large quantities of raw leafy greens to be consumed by blending the leaves with fruit and water. In certain countries of Africa, various species of amaranth are very widely eaten boiled. Celosia argentea var. argentea or Lagos spinach is one of the main boiled greens in West African cuisine, in Greek cuisine, khorta are a common side dish, eaten hot or cold and usually seasoned with olive oil and lemon. Preboggion, a mixture of different wild boiled greens, is used in Ligurian cuisine to stuff ravioli, one of the main ingredients of preboggion are borage leaves
9.
Leaf
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A leaf is an organ of a vascular plant and is the principal lateral appendage of the stem. The leaves and stem together form the shoot, Leaves are collectively referred to as foliage, as in autumn foliage. Although leaves can be seen in different shapes, sizes and textures, typically a leaf is a thin, dorsiventrally flattened organ, borne above ground. Most leaves have distinctive upper surface and lower surface that differ in colour, hairiness, broad, flat leaves with complex venation are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In others, such as the clubmosses, with different evolutionary origins, some leaves, such as bulb scales are not above ground, and in many aquatic species the leaves are submerged in water. Succulent plants often have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls, furthermore, several kinds of leaf-like structures found in vascular plants are not totally homologous with them. Examples include flattened plant stems called phylloclades and cladodes, and flattened leaf stems called phyllodes which differ from both in their structure and origin. Many structures of plants, such as the phyllids of mosses and liverworts and even of some foliose lichens. Leaves are the most important organs of most vascular plants and these are then further processed by chemical synthesis into more complex organic molecules such as cellulose, the basic structural material in plant cell walls. The plant must therefore bring these three together in the leaf for photosynthesis to take place. Once sugar has been synthesized, it needs to be transported to areas of growth such as the plant shoots and roots. Vascular plants transport sucrose in a tissue called the phloem. The phloem and xylem are parallel to each other but the transport of materials is usually in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much as the leaf as possible and they are arranged on the plant so as to expose their surfaces to light as efficiently as possible without shading each other, but there are many exceptions and complications. For instance plants adapted to windy conditions may have pendent leaves, such as in many willows, the flat, or laminar, shape also maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to photosynthesis the leaf is the site of transpiration and guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. For xerophytes the major constraint is not light flux or intensity, some window plants such as Fenestraria species and some Haworthia species such as Haworthia tesselata and Haworthia truncata are examples of xerophytes. and Bulbine mesembryanthemoides
10.
Flower
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A flower, sometimes known as a bloom or blossom, is the reproductive structure found in plants that are floral. The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs, Flowers may facilitate outcrossing or allow selfing. Some flowers produce diaspores without fertilization, Flowers contain sporangia and are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds, the essential parts of a flower can be considered in two parts, the vegetative part, consisting of petals and associated structures in the perianth, and 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, corolla, the next whorl toward the apex, composed of units called petals, which are typically thin, soft and colored to attract animals that help the process of pollination. Androecium, the whorl, consisting of units called stamens. Stamens consist of two parts, a called a filament, topped by an anther where pollen is produced by meiosis. 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 and 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 carpel or 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, 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 generally 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 typically another part, in some families, like Ranunculaceae, the petals are greatly reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens that are petal-like, the flowers of Peonies and Roses are mostly petaloid stamens
11.
Fruit
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In botany, a fruit is the seed-bearing structure in flowering plants formed from the ovary after flowering. Fruits are the means by which angiosperms disseminate seeds, accordingly, fruits account for a substantial fraction of the worlds agricultural output, and some have acquired extensive cultural and symbolic meanings. On the other hand, in usage, fruit includes many structures that are not commonly called fruits, such as bean pods, corn kernels, tomatoes. The section of a fungus that produces spores is called a fruiting body. Many common terms for seeds and fruit do not correspond to the botanical classifications, however, in botany, a fruit is the ripened ovary or carpel that contains seeds, a nut is a type of fruit and not a seed, and a seed is a ripened ovule. Examples of culinary vegetables and nuts that are botanically fruit include corn, cucurbits, eggplant, legumes, sweet pepper, in addition, some spices, such as allspice and chili pepper, are fruits, botanically speaking. g. Botanically, a grain, such as corn, rice, or wheat, is also a kind of fruit. However, the wall is very thin and is fused to the seed coat. The outer, often edible layer, is the pericarp, formed from the ovary and surrounding the seeds, the pericarp may be described in three layers from outer to inner, the epicarp, mesocarp and endocarp. Fruit that bears a prominent pointed terminal projection is said to be beaked, a fruit results from maturation of one or more flowers, and the gynoecium of the flower forms all or part of the fruit. Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the egg cell, after double fertilization, these ovules will become seeds. The ovules are fertilized in a process starts with pollination. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule, later the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo. As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, in some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules. The pericarp is often differentiated into two or three distinct layers called the exocarp, mesocarp, and endocarp, in some fruits, especially simple fruits derived from an inferior ovary, other parts of the flower, fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the fall off. When such other floral parts are a significant part of the fruit, it is called an accessory fruit, since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms. There are three modes of fruit development, Apocarpous fruits develop from a single flower having one or more separate carpels
12.
Seed
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A seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants, Seeds are the product of the ripened ovule, after fertilization by pollen and some growth within the mother plant. The embryo is developed from the zygote and the coat from the integuments of the ovule. Seed plants now dominate biological niches on land, from forests to both in hot and cold climates. The term seed also has a meaning that antedates the above—anything that can be sown, e. g. seed potatoes. In the case of sunflower and corn seeds, what is sown is the seed enclosed in a shell or husk, many structures commonly referred to as seeds are actually dry fruits. Plants producing berries are called baccate, sunflower seeds are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the stone fruits have a hardened fruit layer fused to. Nuts are the one-seeded, hard-shelled fruit of plants with an indehiscent seed. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms from the gymnosperms, angiosperm seeds are produced in a hard or fleshy structure called a fruit that encloses the seeds, hence the name. Some fruits have layers of hard and fleshy material. In gymnosperms, no special structure develops to enclose the seeds, however, the seeds do become covered by the cone scales as they develop in some species of conifer. Seed production in natural plant populations varies widely from year-to-year in response to weather variables, insects and diseases, over a 20-year period, for example, forests composed of loblolly pine and shortleaf pine produced from 0 to nearly 5 million sound pine seeds per hectare. Over this period, there were six bumper, five poor, and nine good seed crops, right after fertilization, the zygote is mostly inactive, but the primary endosperm divides rapidly to form the endosperm tissue. This tissue becomes the food the young plant will consume until the roots have developed after germination, after fertilization the ovules develop into the seeds. The ovule consists of a number of components, The funicle or seed stalk which attaches the ovule to the placenta and hence ovary or fruit wall, the nucellus, the remnant of the megasporangium and main region of the ovule where the megagametophyte develops. The micropyle, a pore or opening in the apex of the integument of the ovule where the pollen tube usually enters during the process of fertilization. The chalaza, the base of the ovule opposite the micropyle, the shape of the ovules as they develop often affects the final shape of the seeds
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Chisholm, Hugh, ed. (1911). "Spinach". Encyclopædia Britannica (11th ed.). Cambridge University Press.
Chisholm, Hugh, ed. (1911). "