1.
Leaf
–
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
Leaf
–
The leaves of a
beech tree
Leaf
–
Near the ground these
Eucalyptus saplings have juvenile dorsiventral foliage from the previous year, but this season their newly sprouting foliage is isobilateral, like the mature foliage on the adult trees above
Leaf
–
A leaf shed in
autumn.
Leaf
–
Cross-section of a leaf
2.
Flower
–
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
Flower
–
A poster with flowers or clusters of flowers produced by twelve species of flowering plants from different families
Flower
–
Main parts of a mature flower (
Ranunculus glaberrimus)
Flower
–
Reproductive parts of Easter Lily (Lilium longiflorum). 1. Stigma, 2. Style, 3. Stamens, 4. Filament, 5. Petal
Flower
–
Left: A normal zygomorphic Streptocarpus flower. Right: An aberrant peloric Streptocarpus flower. Both of these flowers appeared on the Streptocarpus hybrid 'Anderson's Crows' Wings'.
3.
Advertising coloration
–
Advertising in biology means the use of displays by organisms such as animals and plants to signal their presence for some evolutionary reason. Such honest advertising benefits both the sender and the receiver, other animals may advertise dishonestly, in Batesian mimicry, edible animals more or less accurately mimic distasteful animals to reduce their own risk of being attacked by predators. Insect-pollinated flowers use bright colours, patterns, rewards of nectar and pollen, some also use drugs such as caffeine to encourage bees to return more often. Advertising is influenced by selection, in dioecious plants like sallow. Honey bees are attracted by the brighter male flowers. Many flowers that are adapted for pollination by birds produce copious quantities of nectar, insects see red less well than other colours, and the plant needs to devote its energy to attracting birds that can act as pollinators rather than insects that cannot. Advertising takes a variety of forms in animals, breeding adults often display to attract a mate. Breeding males of sexually dimorphic birds, such as peacocks, birds of paradise and bower birds, have elaborate plumage, song and these evolved through sexual selection by females. The males use these features alone or in combination to advertise their presence, in a lek, the presence of multiple males advertises and potentially benefits all the males present, so they are both collaborating and competing. Breeding males may also advertise honestly to warn rival males of their strength, an example being the red deer. The honest advertisement benefits both sender and receiver, as neither need become involved in a fight to assess their relative strength. In the breeding season, frogs congregate at breeding sites and call to advertise their presence. Females can distinguish between the fitness of males based on the characteristics of their voices, desert toads emerge from their underground burrows in response to heavy rain. Males emerge first and when one finds a suitable pool, its call attracts others. Males may call in unison in noisy choruses, and breeding is explosive, colour can be used in advertising. Some butterflies have eyespots on their wings and these make no effort at concealment, but may startle a potential predator into trying elsewhere. The western skink has a blue tail. If the skink cannot escape from a predator by concealment or flight, similarly, some species of grasshopper are well-camouflaged when at rest but flash vivid colouration when flying
Advertising coloration
–
A brilliantly-coloured
oriental sweetlips fish (Plectorhinchus vittatus) waits while two boldly-patterned
cleaner wrasse (Labroides dimidiatus) pick parasites from its skin. The spotted tail and fin pattern of the Sweetlips signals sexual maturity; the behaviour and pattern of the
cleaner fish signal their availability for
cleaning service, rather than as prey
Advertising coloration
–
Bright coloration of orange elephant ear sponge,
Agelas clathrodes signals its bitter taste to predators
Advertising coloration
–
Warning coloration of the
skunk in
Edward Bagnall Poulton 's The Colours of Animals, 1890
Advertising coloration
–
In Roseate Spoonbills 1905-1909,
Abbott Handerson Thayer tried to show that even the bright pink of these conspicuous birds had a
cryptic function.
4.
Pollinator
–
A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the gametes from the pollen grains. Insect pollinators include bees, pollen wasps, ants, flies including bee flies and hoverflies, lepidopterans, vertebrates, mainly bats and birds, but also some non-bat mammals and some lizards pollinate certain plants. Among the pollinating birds are hummingbirds, honeyeaters and sunbirds with long beaks, cycads, which are not flowering plants, are also pollinated by insects. A pollinator is different from a pollenizer, a plant that is a source of pollen for the pollination process, plants fall into pollination syndromes that reflect the type of pollinator being attracted. These are characteristics such as, overall size, the depth and width of the corolla, the color. When these characteristics are experimentally modified, pollinator visitation may decline and it has recently been discovered that cycads, which are not flowering plants, are also pollinated by insects. The most recognized pollinators are the species of bees, which are plainly adapted to pollination. Bees typically are fuzzy and carry an electrostatic charge, Honey bees, bumblebees, and their relatives do not have a scopa, but the hind leg is modified into a structure called the corbicula. Most bees gather nectar, an energy source, and pollen, which is high protein food, to nurture their young. Euglossine bees pollinate orchids, but these are male bees collecting floral scents rather than females gathering nectar or pollen, female orchid bees act as pollinators, but of flowers other than orchids. Eusocial bees such as honey bees need an abundant and steady pollen source to multiply, Honey bees travel from flower to flower, collecting nectar, and pollen grains. The bee collects the pollen by rubbing against the anthers, the pollen collects on the hind legs, in a structure referred to as a pollen basket. As the bee flies from flower to flower, some of the grains are transferred onto the stigma of other flowers. Nectar provides the energy for bee nutrition, pollen provides the protein, when bees are rearing large quantities of brood, bees deliberately gather pollen to meet the nutritional needs of the brood. Good pollination management seeks to have bees in a state during the bloom period of the crop, thus requiring them to gather pollen. Thus, the management techniques of a beekeeper providing pollination services are different from, and to some extent in tension with, many insects other than bees accomplish pollination by visiting flowers for nectar or pollen, or commonly both. Many do so adventitiously, but the most important pollinators are specialists for at least parts of their lifecycles for at least certain functions
Pollinator
–
A syrphid fly (
Eristalinus taeniops) pollinating a
common hawkweed
Pollinator
–
Lipotriches sp. bee pollinating flowers
Pollinator
–
Honey bee with pollen adhering: Bees are the most effective insect pollinators.
Pollinator
–
An
Australian painted lady with its proboscis extended during feeding. Butterflies are recognised pollinators though not as effective as
bees.
5.
Sepal
–
A sepal is a part of the flower of angiosperms. Usually green, sepals typically function as protection for the flower in bud, the term sepalum was coined by Noël Martin Joseph de Necker in 1790, and derived from the Greek σκεπη, a covering. Collectively the sepals are called the calyx, the outermost whorl of parts that form a flower, the word calyx was adopted from the Latin calyx, not to be confused with calix, a cup or goblet. Calyx derived from the Greek κάλυξ, a bud, a calyx, a husk or wrapping, while derived from the Greek κυλιξ, a cup or goblet. After flowering, most plants have no use for the calyx which withers or becomes vestigial. Some plants retain a thorny calyx, either dried or live, examples include species of Acaena, some of the Solanaceae, and the water caltrop, Trapa natans. In some species the calyx not only persists after flowering, but instead of withering and this is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and the Cape gooseberry. Morphologically, both sepals and petals are modified leaves, the calyx and the corolla are the outer sterile whorls of the flower, which together form what is known as the perianth. The term tepal is usually applied when the parts of the perianth are difficult to distinguish, e. g. the petals and sepals share the same color, or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as petaloid, as in petaloid monocots, since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Aloe, in contrast, genera such as Rosa and Phaseolus have well-distinguished sepals and petals. The number of sepals in a flower is its merosity, flower merosity is indicative of a plants classification. The merosity of a flower is typically four or five. The merosity of a monocot or palaeodicot flower is three, or a multiple of three, the development and form of the sepals vary considerably among flowering plants. They may be free or fused together, often, the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most often such structures protrude until the fruit is mature and falls off, examples of flowers with much reduced perianths are found among the grasses. In some flowers, the sepals are fused towards the base, in other flowers a hypanthium includes the bases of sepals, petals, and the attachment points of the stamens
Sepal
–
Tetramerous flower of
Ludwigia octovalvis showing petals and sepals.
Sepal
–
Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals)
Sepal
–
After blooming, the sepals of
Hibiscus sabdariffa expand into an edible
accessory fruit
Sepal
–
In many Fabaceae flowers, a calyx tube surrounds the petals.
6.
Perianth
–
The perianth is the non-reproductive part of the flower, and 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, peri, meaning around, in the mosses and liverworts, the perianth is the sterile tubelike tissue that surrounds the female reproductive structure. When the perianth is in two whorls, it is described as biseriate, while the calyx may be green, it may also be brightly coloured, and is then described as petaloid. When the undifferentiated tepals resemble petals, they are referred to as petaloid, as in petaloid monocots. Since they include Liliales, a name is lilioid monocots. The corolla and petals have a role in attracting pollinators, 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 entirely absent, the perianth can be described as being monochlamydeous. Both sepals and petals may have stomata and veins, even 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 also 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 often positioned where the corolla lobes arise from the corolla tube, the pappus of Asteraceae, considered to be a modified calyx, is also called a corona if it is shaped like a crown. The dictionary definition of perianth at Wiktionary
Perianth
–
Flower of Narcissus showing an outer white corolla with a central yellow corona (paraperigonium)
Perianth
–
Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals)
Perianth
–
Flower of
Passiflora incarnata showing corona of fine appendages between petals and stamens
7.
Tepal
–
A tepal is one of the outer parts of a flower when these parts cannot easily be divided into two kinds, sepals and petals. The term was first proposed by Augustin Pyramus de Candolle in 1827, undifferentiated tepals are believed to be the ancestral condition in flowering plants. For example, Amborella, which is thought to have separated earliest in the evolution of flowering plants, has flowers with undifferentiated tepals, distinct petals and sepals would therefore have arisen by differentiation, probably in response to animal pollination. Tepals formed by similar sepals and petals are common in monocotyledons, in tulips, for example, the first and second whorls both contain structures that look like petals. These are fused at the base to one large, showy. In lilies the organs in the first whorl are separate from the second, where sepals and petals can in principle be distinguished, usage of the term tepal is not always consistent – some authors will refer to sepals and petals where others use tepals in the same context. In some plants the flowers have no petals, and all the tepals are sepals modified to look like petals and these organs are described as petaloid, for example, the sepals of hellebores. When the undifferentiated tepals resemble petals, they are referred to as petaloid, as in petaloid monocots. Since they include Liliales, a name is lilioid monocots. Terms used in the description of tepals include pubescent, puberulent, tepal shape is described in similar terms to those used for leaves. Plant Systematics - Jones, Samuel - McGraw-Hill 1979 ISBN 0-07-032795-5
Tepal
–
A
Lilium flower showing the six tepals: the inner three are petals and the outer three are sepals.
Tepal
–
Diagram showing the parts of a mature flower. In this example the perianth is separated into a calyx (sepals) and corolla (petals)
Tepal
–
Flowers of
Magnolia × alba showing tepals in various stages of development
Tepal
–
A tulip flower showing the petal-like tepals
8.
Genus
–
A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of classification, genus comes above species. In binomial nomenclature, the name forms the first part of the binomial species name for each species within the genus. Felis catus and Felis silvestris are two species within the genus Felis, Felis is a genus within the family Felidae. The composition of a genus is determined by a taxonomist, the standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. Moreover, genera should be composed of units of the same kind as other genera. The term comes from the Latin genus, a noun form cognate with gignere, linnaeus popularized its use in his 1753 Species Plantarum, but the French botanist Joseph Pitton de Tournefort is considered the founder of the modern concept of genera. The scientific name of a genus may be called the name or generic epithet. It plays a role in binomial nomenclature, the system of naming organisms. The rules for the names of organisms are laid down in the Nomenclature Codes. The standard way of scientifically describing species and other lower-ranked taxa is by binomial nomenclature, the generic name forms its first half. For example, the gray wolfs binomial name is Canis lupus, with Canis being the name shared by the wolfs close relatives. The specific name is written in lower-case and may be followed by names in zoology or a variety of infraspecific names in botany. Especially with these names, when the generic name is known from context. Because animals are typically only grouped within subspecies, it is written as a trinomen with a third name. Dog breeds, meanwhile, are not scientifically distinguished, there are several divisions of plant species and therefore their infraspecific names generally include contractions explaining the relation. For example, the genus Hibiscus includes hundreds of other species apart from the Rose of Sharon or common garden hibiscus, Rose of Sharon doesnt have subspecies but has cultivars that carry desired traits, such as the bright white H. syriaca Diana. Hawaiian hibiscus, meanwhile, includes several separate species, since not all botanists agree on the divisions or names between species, it is common to specify the source of the name using author abbreviations
Genus
–
Number of reptile genera with a given number of species. Most genera have only one or a few species but a few may have hundreds. Based on data from the
Reptile Database (as of May 2015).
9.
Aloe
–
Aloe, also written Aloë, is a genus containing over 500 species of flowering succulent plants. The most widely known species is Aloe vera, or true aloe, other species, such as Aloe ferox, also are cultivated or harvested from the wild for similar applications. The APG IV system places the genus in the family Asphodelaceae, in the past, it has been assigned to the family Aloaceae or to a broadly circumscribed family Liliaceae. The plant Agave americana, which is sometimes called American aloe, belongs to the Asparagaceae, the genus is native to tropical and southern Africa, Madagascar, Jordan, the Arabian Peninsula, and various islands in the Indian Ocean. A few species have become naturalized in other regions. Most Aloe species have a rosette of large, thick, fleshy leaves, Aloe flowers are tubular, frequently yellow, orange, pink, or red, and are borne, densely clustered and pendant, at the apex of simple or branched, leafless stems. Many species of Aloe appear to be stemless, with the rosette growing directly at ground level and they vary in color from grey to bright-green and are sometimes striped or mottled. Some aloes native to South Africa are tree-like, the APG IV system places the genus in the family Asphodelaceae, subfamily Asphodeloideae. In the past it has also assigned to the families Liliaceae and Aloeaceae, as well as the family Asphodelaceae sensu stricto. The circumscription of the genus has varied widely, many genera, such as Lomatophyllum, have been brought into synonymy. Species at one time placed in Aloe, such as Agave americana, have moved to other genera. Over 500 species are accepted in the genus Aloe, plus even more synonyms and unresolved species, subspecies, varieties, Aloe species are frequently cultivated as ornamental plants both in gardens and in pots. Many aloe species are highly decorative and are valued by collectors of succulents, Aloe vera is used both internally and externally on humans, and is claimed to have some medicinal effects, which have been supported by scientific and medical research. They can also be made into types of special soaps, historical use of various aloe species is well documented. Documentation of the effectiveness is available, although relatively limited. Of the 500+ species, only a few were used traditionally as herbal medicines, also included are A. perryi and A. ferox. The Ancient Greeks and Romans used Aloe vera to treat wounds, in the Middle Ages, the yellowish liquid found inside the leaves was favored as a purgative. Unprocessed aloe that contains aloin is generally used as a laxative, some species, particularly Aloe vera, are used in alternative medicine and first aid
Aloe
–
Aloe
Aloe
–
Succulent plants, such as this aloe, store water in their enlarged fleshy leaves, stems, or roots, as shown in this split aloe leaf. This allows them to survive in arid environments.
Aloe
–
Aloe vossii
Aloe
–
Aloe ferox ("Cape Aloe")
10.
Tulipa
–
The tulip is a Eurasian and North African genus of perennial, bulbous plants in the lily family. It is a herb with showy flowers, of which around 75 wild species are currently accepted. The tulips centre of diversity is in the Pamir, Hindu Kush and it is a common element of steppe and winter-rain Mediterranean vegetation. A number of species and many cultivars are grown in gardens or as potted plants. Tulips are spring-blooming perennials that grow from bulbs, depending on the species, tulip plants can be between 4 inches and 28 inches high. The tulips large flowers usually bloom on scapes with leaves in a rosette at ground level, larger species tend to have multiple leaves. Plants typically have two to six leaves, some species up to 12, the tulips leaf is strap-shaped, with a waxy coating, and the leaves are alternately arranged on the stem, these fleshy blades are often bluish green in color. Most tulips produce only one flower per stem, but a few species bear multiple flowers on their scapes, the generally cup or star-shaped tulip flower has three petals and three sepals, which are often termed tepals because they are nearly identical. These six tepals are often marked on the surface near the bases with darker colorings. Tulip flowers come in a variety of colors, except pure blue. The flowers have six distinct, basifixed stamens with filaments shorter than the tepals, each stigma has three distinct lobes, and the ovaries are superior, with three chambers. The tulips seed is a capsule with a covering and an ellipsoid to globe shape. Each capsule contains numerous flat, disc-shaped seeds in two rows per chamber and these light to dark brown seeds have very thin seed coats and endosperm that does not normally fill the entire seed. Tulipanin is a found in tulips. It is the 3-rutinoside of delphinidin, the chemical compounds named tuliposides and tulipalins can also be found in tulips and are responsible for allergies. Tulipalin A, or α-methylene-γ-butyrolactone, is an allergen, generated by hydrolysis of the glucoside tuliposide A. It induces a dermatitis that is mostly occupational and affects tulip bulb sorters and florists who cut the stems, tulipanin A and B are toxic to horses, cats and dogs. The genus Tulipa was traditionally divided into two sections, Eriostemones and Tulipa, and comprises ca.76 species
Tulipa
–
Tulip
Tulipa
–
Tulipa agenensis in
Israel (details).
Tulipa
–
Tip of a tulip stamen. Note the pollen grains
Tulipa
–
Tulipa agenensis in
Jerusalem forest,
Israel
11.
Rose
–
A rose is a woody perennial flowering plant of the genus Rosa, in the family Rosaceae, or the flower it bears. There are over a species and thousands of cultivars. They form a group of plants that can be erect shrubs, flowers vary in size and shape and are usually large and showy, in colours ranging from white through yellows and reds. Most species are native to Asia, with smaller numbers native to Europe, North America, species, cultivars and hybrids are all widely grown for their beauty and often are fragrant. Roses have acquired cultural significance in many societies, Rose plants range in size from compact, miniature roses, to climbers that can reach seven meters in height. Different species hybridize easily, and this has used in the development of the wide range of garden roses. The leaves are borne alternately on the stem, most roses are deciduous but a few are evergreen or nearly so. The flowers of most species have five petals, with the exception of Rosa sericea, each petal is divided into two distinct lobes and is usually white or pink, though in a few species yellow or red. Beneath the petals are five sepals and these may be long enough to be visible when viewed from above and appear as green points alternating with the rounded petals. There are multiple superior ovaries that develop into achenes, the aggregate fruit of the rose is a berry-like structure called a rose hip. Many of the domestic cultivars do not produce hips, as the flowers are so tightly petalled that they do not provide access for pollination, the hips of most species are red, but a few have dark purple to black hips. Each hip comprises an outer layer, the hypanthium, which contains 5–160 seeds embedded in a matrix of fine. Rose hips of some species, especially the dog rose and rugosa rose, are rich in vitamin C. The hips are eaten by fruit-eating birds such as thrushes and waxwings, some birds, particularly finches, also eat the seeds. While the sharp objects along a stem are commonly called thorns. Rose prickles are typically sickle-shaped hooks, which aid the rose in hanging onto other vegetation growing over it. Despite the presence of prickles, roses are frequently browsed by deer, a few species of roses have only vestigial prickles that have no points. Hesperrhodos contains Rosa minutifolia and Rosa stellata, from North America, platyrhodon with one species from east Asia, Rosa roxburghii
Rose
–
Rose
Rose
–
Cross-section through a developing rose hip
Rose
–
Exterior view of rose buds
Rose
–
Rose leaflets
12.
Phaseolus
–
Phaseolus is a genus in the family Fabaceae containing about 70 plant species, all native to the Americas, primarily Mesoamerica. At least four of the species have been domesticated since pre-Columbian times for their beans, most prominent among these is the common bean, P. vulgaris, which today is cultivated worldwide in tropical, semitropical, and temperate climates. Previous classifications placed in this genus a number of other species that have now been removed to genus Vigna. For example, older literature refers to the bean as Phaseolus aureus. Similarly, the snail bean Vigna caracalla was discovered in 1753, the modern understanding of Phaseolus indicates a genus endemic to the New World alone. Phaseolus species are used as food plants by the larvae of some Lepidoptera species, including common swift, garden dart, ghost moth Hypercompe albicornis, H. icasia and the nutmeg
Phaseolus
–
Phaseolus
13.
Petaloid monocots
–
Lilioid monocots is an informal name used for a grade of five monocot orders in which the majority of species have flowers with relatively large, coloured tepals. This characteristic is similar to found in lilies. Petaloid monocots refers to the flowers having tepals which all resemble petals, the taxonomic terms Lilianae or Liliiflorae have also been applied to this assemblage at various times. From the early nineteenth century many of the species in group of plants were put into a very broadly defined family. These classification systems are found in many books and other sources. Within the monocots the Liliaceae s. l. were distinguished from the Glumaceae and this has resulted in treating monocots as three informal groups, alismatid, lilioid and commelinid monocots. The lilioids are paraphyletic in the sense that commelinids form a group to Asparagales. The descriptive term petaloid lilioid monocot relates to the conspicuous petal-like tepals which superficially resemble true lilies, morphologically, the petaloid or lilioid monocots can be considered to possess five groups of three-fold whorls. Lilioid monocots all have flowers which can be considered to have derived from a lily-like flower with six relatively similar tepals. However, floral synapomorphy is rare since most conform to the general monocot pattern and this pattern is ancestral for the lilioid monocots. Structural monosymmetry is rare, except for Orchidaceae, various trends are apparent among the lilioids, notably a change to an inferior ovary and a reduction of the number of stamens to three. In some groups, the tepals have become clearly differentiated, so that the flower has three coloured petals and three green sepals. Almost all lilioid monocots retain at least three petal-like tepals, the morphological concept of petaloid monocots has been equated with animal-attracting as opposed to wind-pollinating plants that have evolved very different floral structures. Pollen structure shows that of the two main types, secretory and plasmodial, the lilioid monocots are nearly all secretory. In the orders that branched off before the lilioid monocots, the Acorales and Alismatales, in some cases, like Acorus, they have become insignificant. In others, like Butomus, they have six coloured tepals, and so could be called petaloid, the later evolved commelinids have various kinds of flower, few of which are lily-like. In the order Poales, comprising grasses, rushes and sedges, flowers are either petal-less or have small, many Zingiberales species have brightly coloured and showy flowers. However, their apparent structure is misleading, for example, the six tepals of cannas are small and hidden under expanded and brightly coloured stamens or staminodes which resemble petals and may be mistaken for them
Petaloid monocots
–
The pink structures in this canna flower look like tepals, but are actually expanded stamens or staminodes
14.
Liliales
–
Liliales is an order of monocotyledonous flowering plants in the Angiosperm Phylogeny Group and Angiosperm Phylogeny Web system, within the lilioid monocots. This order of necessity includes the family Liliaceae, the APG III system places this order in the monocot clade. In APG III, the family Luzuriagaceae is combined with the family Alstroemeriaceae, both the Lililiales order and the Liliaceae family have had a widely disputed history, with the circumscription varying greatly from one taxonomist to another. The newly delimited Liliales is monophyletic, with ten families, well known plants from the order include Lilium, tulip, the North American wildflower Trillium, and greenbrier. Thus circumscribed, this consists mostly of herbaceous plants, but lianas. They are mostly perennial plants, with food storage organs such as corms or rhizomes, the family Corsiaceae is notable for being heterotrophic. The larger families are confined to the Northern Hemisphere, or are distributed worldwide. On the other hand, the families are confined to the Southern Hemisphere. The total number of species in the order is now about 1300, as with any herbaceous group, the fossil record of the Liliales is rather scarce. There are several species from the Eocene, such as Petermanniopsis anglesaensis or Smilax, another known fossil is Ripogonum scandens from the Miocene. Due to the scarcity of data, it impossible to determine precisely the age. It is assumed that the Liliales originate from the Lower Cretaceous, the initial diversification to the current families took place between 82 and 48 million years ago. The order consists of 10 families,67 genera and about 1,500 species, the Liliales are characterised by the presence of nectaries at the base of the tepals or stamen filaments, together with extrorse anthers. This distinguishes them from the septal nectaries and introrse anthers that are the features of most other monocots and they are mainly geophytes with elliptical leaves showing fine reticulate venation. The tepals are large and pointed. The outer integument epidermis of the coat is cellular. The inner integument is also cellular and these features are plesiomorphic, the Liliales are predominantly perennial erect or twining herbaceous and climbing plants. They also include woody shrubs, which have fleshy stems and underground storage or perennating organs, earlier names for this order include the Coronarieae of the Bentham & Hooker system
Liliales
15.
Poaceae
–
Poaceae or Gramineae is a large and nearly ubiquitous family of monocotyledonous flowering plants known as grasses. Poaceae includes the cereal grasses, bamboos and the grasses of natural grassland and cultivated lawns, Grasses have stems that are hollow except at the nodes and narrow alternate leaves borne in two ranks. The lower part of each leaf encloses the stem, forming a leaf-sheath, with ca 780 genera and around 12,000 species, Poaceae are the fifth-largest plant family, following the Asteraceae, Orchidaceae, Fabaceae and Rubiaceae. Grasslands such as savannah and prairie grasses are dominant are estimated to constitute 40. 5% of the land area of the Earth, excluding Greenland. Grasses are also an important part of the vegetation in many habitats, including wetlands, forests. Though commonly called grasses, seagrasses, rushes, and sedges fall outside this family, the rushes and sedges are related to the Poaceae, being members of the order Poales, but the seagrasses are members of order Alismatales. The name Poaceae was given by John Hendley Barnhart in 1895, based on the tribe Poeae described in 1814 by Robert Brown, the term is derived from the Ancient Greek πόα. Grasses include some of the most versatile plant life-forms, a cladogram shows subfamilies and approximate species numbers in brackets, Before 2005, fossil findings indicated that grasses evolved around 55 million years ago. Recent findings of grass-like phytoliths in Cretaceous dinosaur coprolites have pushed this back to 66 million years ago. In 2011, revised dating of the origins of the rice tribe Oryzeae suggested a date as early as 107 to 129 Mya, a multituberculate mammal with grass-eating adaptations seems to suggest that grasses were already around at 120 mya. This separation occurred within the short time span of about 4 million years. Grass leaves are always alternate and distichous, and have parallel veins. Each leaf is differentiated into a lower sheath hugging the stem, the leaf blades of many grasses are hardened with silica phytoliths, which discourage grazing animals, some, such as sword grass, are sharp enough to cut human skin. A membranous appendage or fringe of hairs called the ligule lies at the junction between sheath and blade, preventing water or insects from penetrating into the sheath, flowers of Poaceae are characteristically arranged in spikelets, each having one or more florets. The spikelets are further grouped into panicles or spikes, the part of the spikelet that bears the florets is called the rachilla. A spikelet consists of two bracts at the base, called glumes, followed by one or more florets, a floret consists of the flower surrounded by two bracts, one external—the lemma—and one internal—the palea. The flowers are usually hermaphroditic—maize being an important exception—and anemophilous or wind-pollinated, the perianth is reduced to two scales, called lodicules, that expand and contract to spread the lemma and palea, these are generally interpreted to be modified sepals. This complex structure can be seen in the image on the right, the fruit of grasses is a caryopsis, in which the seed coat is fused to the fruit wall
Poaceae
Poaceae
–
Grass flowers
Poaceae
–
Setaria verticillata from
Panicoideae
Poaceae
–
Tragus roxburghii from
Chloridoideae
16.
Tetramery (botany)
–
Merosity is the number of component parts in each whorl of a plant structure. The term may also be used to refer to the number of leaves in leaf whorls, P. Ronse, Smets, E. F. Merosity in flowers, Definition, origin, and taxonomic significance
Tetramery (botany)
–
Trimerous flower of
Tulipa clusiana (the three sepals resemble petals)
Tetramery (botany)
–
Tetramerous flower of
Correa alba
Tetramery (botany)
–
Pentamerous flower of
Crassula ovata
17.
Onagraceae
–
The Onagraceae are a family, known as the willowherb family or evening primrose family, of flowering plants. They include about 650 species of herbs, shrubs, and trees in 17 genera, the family is widespread, occurring on every continent from boreal to tropical regions. The family includes a number of garden plants, including evening primroses. Some, particularly the willowherbs are common weeds in gardens and in the wild, the family is characterised by flowers with usually four sepals and petals, in some genera, such as Fuchsia, the sepals are as brightly coloured as the petals. The seeds are very small. In some genera, such as Epilobium, they have tufts of hairs and are dispersed on the wind, in others, such as Fuchsia, the seeds develop in juicy berries dispersed by animals. The leaves are commonly opposite or whorled, but are arranged in some species, in most, they are simple. The pollen grains in many genera are loosely held together by viscin threads, the family is named after the genus Onagra in 1836 by John Lindley in the second edition of A Natural System of Botany. Ludwigia L. Smithsonian Institution, Onagraceae classification
Onagraceae
–
Onagraceae
Onagraceae
–
Circaea alpina
Onagraceae
–
Epilobium alpestre
Onagraceae
–
Fuchsia magellanica
18.
Tulip
–
The tulip is a Eurasian and North African genus of perennial, bulbous plants in the lily family. It is a herb with showy flowers, of which around 75 wild species are currently accepted. The tulips centre of diversity is in the Pamir, Hindu Kush and it is a common element of steppe and winter-rain Mediterranean vegetation. A number of species and many cultivars are grown in gardens or as potted plants. Tulips are spring-blooming perennials that grow from bulbs, depending on the species, tulip plants can be between 4 inches and 28 inches high. The tulips large flowers usually bloom on scapes with leaves in a rosette at ground level, larger species tend to have multiple leaves. Plants typically have two to six leaves, some species up to 12, the tulips leaf is strap-shaped, with a waxy coating, and the leaves are alternately arranged on the stem, these fleshy blades are often bluish green in color. Most tulips produce only one flower per stem, but a few species bear multiple flowers on their scapes, the generally cup or star-shaped tulip flower has three petals and three sepals, which are often termed tepals because they are nearly identical. These six tepals are often marked on the surface near the bases with darker colorings. Tulip flowers come in a variety of colors, except pure blue. The flowers have six distinct, basifixed stamens with filaments shorter than the tepals, each stigma has three distinct lobes, and the ovaries are superior, with three chambers. The tulips seed is a capsule with a covering and an ellipsoid to globe shape. Each capsule contains numerous flat, disc-shaped seeds in two rows per chamber and these light to dark brown seeds have very thin seed coats and endosperm that does not normally fill the entire seed. Tulipanin is a found in tulips. It is the 3-rutinoside of delphinidin, the chemical compounds named tuliposides and tulipalins can also be found in tulips and are responsible for allergies. Tulipalin A, or α-methylene-γ-butyrolactone, is an allergen, generated by hydrolysis of the glucoside tuliposide A. It induces a dermatitis that is mostly occupational and affects tulip bulb sorters and florists who cut the stems, tulipanin A and B are toxic to horses, cats and dogs. The genus Tulipa was traditionally divided into two sections, Eriostemones and Tulipa, and comprises ca.76 species
Tulip
–
Tulip
Tulip
–
Tulipa agenensis in
Israel (details).
Tulip
–
Tip of a tulip stamen. Note the pollen grains
Tulip
–
Tulipa agenensis in
Jerusalem forest,
Israel
19.
Evolution
–
Evolution is change in the heritable characteristics of biological populations over successive generations. Evolutionary processes give rise to biodiversity at every level of organisation, including the levels of species, individual organisms. In July 2016, scientists reported identifying a set of 355 genes from the LUCA of all living on Earth. The fossil record includes a progression from early biogenic graphite, to microbial mat fossils, existing patterns of biodiversity have been shaped both by speciation and by extinction. More than 99 percent of all species that lived on Earth are estimated to be extinct. Estimates of Earths current species range from 10 to 14 million, more recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described. In the mid-19th century, Charles Darwin formulated the theory of evolution by natural selection. This teleonomy is the quality whereby the process of natural selection creates and preserves traits that are fitted for the functional roles they perform. The processes by which the changes occur, from one generation to another, are called evolutionary processes or mechanisms, the four most widely recognized evolutionary processes are natural selection, genetic drift, mutation and gene migration. Natural selection and genetic drift sort variation, mutation and gene migration create variation, consequences of selection can include meiotic drive, nonrandom mating and genetic hitchhiking. In the early 20th century the modern evolutionary synthesis integrated classical genetics with Darwins theory of evolution by natural selection through the discipline of population genetics, the importance of natural selection as a cause of evolution was accepted into other branches of biology. Moreover, previously held notions about evolution, such as orthogenesis, evolutionism, evolutionary computation, a sub-field of artificial intelligence, involves the application of Darwinian principles to problems in computer science. The proposal that one type of organism could descend from another type goes back to some of the first pre-Socratic Greek philosophers, such as Anaximander, such proposals survived into Roman times. The poet and philosopher Lucretius followed Empedocles in his masterwork De rerum natura, in contrast to these materialistic views, Aristotelianism considered all natural things as actualisations of fixed natural possibilities, known as forms. This was part of a teleological understanding of nature in which all things have an intended role to play in a divine cosmic order. In the 17th century, the new method of modern science rejected the Aristotelian approach, however, this new approach was slow to take root in the biological sciences, the last bastion of the concept of fixed natural types. The biological classification introduced by Carl Linnaeus in 1735 explicitly recognized the nature of species relationships. Other naturalists of this time speculated on the change of species over time according to natural laws
Evolution
–
Lucretius
Evolution
Evolution
–
Alfred Russel Wallace
Evolution
–
Thomas Robert Malthus
20.
Charles Darwin
–
Charles Robert Darwin, FRS FRGS FLS FZS was an English naturalist, geologist and biologist, best known for his contributions to the science of evolution. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species, by the 1870s, the scientific community and much of the general public had accepted evolution as a fact. In modified form, Darwins scientific discovery is the theory of the life sciences. Darwins early interest in nature led him to neglect his education at the University of Edinburgh, instead. Studies at the University of Cambridge encouraged his passion for natural science, puzzled by the geographical distribution of wildlife and fossils he collected on the voyage, Darwin began detailed investigations and in 1838 conceived his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research and he was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting immediate joint publication of both of their theories. Darwins work established evolutionary descent with modification as the dominant scientific explanation of diversification in nature, in 1871 he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex, followed by The Expression of the Emotions in Man and Animals. His research on plants was published in a series of books, Darwin has been described as one of the most influential figures in human history, and he was honoured by burial in Westminster Abbey. Charles Robert Darwin was born in Shrewsbury, Shropshire, on 12 February 1809, at his familys home and he was the fifth of six children of wealthy society doctor and financier Robert Darwin and Susannah Darwin. He was the grandson of two prominent abolitionists, Erasmus Darwin on his fathers side, and Josiah Wedgwood on his mothers side, both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. The eight-year-old Charles already had a taste for history and collecting when he joined the day school run by its preacher in 1817. From September 1818, he joined his older brother Erasmus attending the nearby Anglican Shrewsbury School as a boarder and he found lectures dull and surgery distressing, so neglected his studies. He learned taxidermy in around 40 daily hour-long sessions from John Edmonstone, one day, Grant praised Lamarcks evolutionary ideas. Darwin was astonished by Grants audacity, but had recently read similar ideas in his grandfather Erasmus journals, Darwin was rather bored by Robert Jamesons natural-history course, which covered geology - including the debate between Neptunism and Plutonism. He learned the classification of plants, and assisted with work on the collections of the University Museum, as Darwin was unqualified for the Tripos, he joined the ordinary degree course in January 1828. He preferred riding and shooting to studying, when his own exams drew near, Darwin focused on his studies and was delighted by the language and logic of William Paleys Evidences of Christianity. In his final examination in January 1831 Darwin did well, coming out of 178 candidates for the ordinary degree. Darwin had to stay at Cambridge until June 1831, inspired with a burning zeal to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics
Charles Darwin
–
Portrait photograph of Darwin, probably taken in 1854 when he was 45 years old and working towards publication of
On the Origin of Species
Charles Darwin
–
Painting of seven-year-old Charles Darwin in 1816.
Charles Darwin
–
As
HMS Beagle surveyed the coasts of South America, Darwin theorised about geology and extinction of giant mammals.
Charles Darwin
–
Darwin chose to marry his cousin,
Emma Wedgwood.
21.
Spathe
–
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves and they may be smaller, larger, or of a different color, shape, or texture. Typically, they look different from the parts of the flower. The state of having bracts is referred to as bracteate or bracteolate, some bracts are brightly colored and serve the function of attracting pollinators, either together with the perianth or instead of it. Examples of this type of bract include Euphorbia pulcherrima and Bougainvillea, in grasses, each floret is enclosed in a pair of papery bracts, called the lemma and palea, while each spikelet has a further pair of bracts at its base called glumes. These bracts form the chaff removed from cereal grain during threshing and winnowing, bats may detect acoustic signals from dish-shaped bracts such as those of Marcgravia evenia. A prophyll is a structure, such as a bracteole. The term can mean the lower bract on a peduncle. The frequently showy pair of bracts of Euphorbia species in subgenus Lacanthis are the cyathophylls, bracts subtend the cone scales in the seed cones of many conifers, and in some cases, such as Pseudotsuga, they extend beyond the cone scales. A small bract is called a bracteole or bractlet, technically this is any bract that arises on a pedicel instead of subtending it. Bracts that appear in a whorl subtending an inflorescence are called an involucre. An involucre is a common feature beneath the inflorescences of many Apiaceae, Asteraceae, Dipsacaceae and Polygonaceae, each flower in an inflorescence may have its own whorl of bracts, in this case called an involucel. In this case they may be called chaff, paleas, or receptacular bracts and are usually minute scales or bristles, many asteraceous plants have bracts at the base of each inflorescence. The term involucre is also used for a highly conspicuous bract or bract pair at the base of an inflorescence, in the family Betulaceae, notably in the genera Carpinus and Corylus, the involucre is a leafy structure that protects the developing nuts. Beggar-tick has narrow involucral bracts surrounding each inflorescence, each of which also has a bract below it. There is then a pair of bracts on the main stem. It is a calyx-like extra whorl of floral appendages, each individual segment of the epicalyx is called an episepal because they resemble the sepals. They are present in family Malvaceae, the Hibiscus family, fragaria may or may not have an epicalyx
Spathe
–
Papery (upper) and leafy bracts on hay rattle (
Rhinanthus minor). All the "leaves" in this image are bracts.
Spathe
–
Bracts of
Bougainvillea glabra, differ in colour from the non-bract leaves, and attract pollinators
Spathe
–
Bracts along a
banana flower stalk surround the rows of flowers
Spathe
–
Euphorbia milii var. vulcanii cyathia bearing a pair of pinkish cyathophylls
22.
Floral cup
–
In angiosperms, a hypanthium or floral cup is a structure where basal portions of the calyx, the corolla, and the stamens form a cup-shaped tube. It is sometimes called a tube, a term that is also used for corolla tube. It often contains the nectaries of the plant and it is present in most flowering species, although varies in structural dimensions and appearance. This differentiation between the hypanthium in particular species is useful with identification, some geometric forms are obconic shapes as in toyon, whereas some are saucer-shaped as in Mitella caulescens. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, in some cases, it can be so deep, with such a narrow top, that the flower can appear to have an inferior ovary - the ovary is below the other attached floral parts. The hypanthium is known by different common names in differing species, in the eucalypts, it is referred to as the gum nut, in roses it is called the hip. In myrtles the hypanthium can either surround the ovary loosely or tightly, the rims around the outside of the hypanthium contain the calyx lobes or free sepals, petals and either the stamen or multiple stamen that are attached at one or two points. The flowers of the Rosaceae family always have some type of hypanthium or at least a floral cup from which the sepals, petals, in the Rosaceae family, or the rose family, the hypanthium is lined with nectar-producing tissue known as nectaries. The stamens borne on the hypanthium are the reproductive organs of the flower. The hypanthium helps in many ways with the reproduction and cross pollination pathways of most plants and it provides weather protection and a medium to sustain the lost pollen, increasing the probability of fertility and cross-pollination. The retained pollen can then attach to such as birds, bees, moths, beetles, bats, butterflies. Wind can act as an instigator for fertilisation, the hypanthium is also an adaptive feature for structural support. It helps the stem fuse together with the flower, in turn strengthening the bond, hypanthium images on MorphBank, a biological image database
Floral cup
–
In a pomegranate flower,
Punica granatum, the
petals, except for their fused bases, soon fall. The hypanthium with
sepal lobes and
stamens still attached develops to form the outer layer of the fruit.
Floral cup
Floral cup
–
Narcissus pseudonarcissus, showing from the upper bend to the tip of the flower:
spathe, ovary, hypanthium,
tepals,
corona
23.
Merosity
–
Merosity is the number of component parts in each whorl of a plant structure. The term may also be used to refer to the number of leaves in leaf whorls, P. Ronse, Smets, E. F. Merosity in flowers, Definition, origin, and taxonomic significance
Merosity
–
Trimerous flower of
Tulipa clusiana (the three sepals resemble petals)
Merosity
–
Tetramerous flower of
Correa alba
Merosity
–
Pentamerous flower of
Crassula ovata
24.
Eudicots
–
The eudicots, Eudicotidae or eudicotyledons are a monophyletic clade of flowering plants that had been called tricolpates or non-magnoliid dicots by previous authors. The close relationships among flowering plants with tricolpate pollen grains was initially seen in studies of shared derived characters. These plants have a trait in their pollen grains of exhibiting three colpi or grooves paralleling the polar axis. Later molecular evidence confirmed the basis for the evolutionary relationships among flowering plants with tricolpate pollen grains. The term means true dicotyledons, as it contains the majority of plants that have been considered dicots and have characteristics of the dicots, the term eudicots has subsequently been widely adopted in botany to refer to one of the two largest clades of angiosperms, monocots being the other. The remaining angiosperms are sometimes referred to as basal angiosperms or paleodicots, the other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen, or forms derived from it and these pollens have three or more pores set in furrows called colpi. In contrast, most of the seed plants produce monosulcate pollen. The name tricolpates is preferred by some botanists to avoid confusion with the dicots, numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Most leafy trees of midlatitudes also belong to eudicots, with exceptions being magnolias and tulip trees which belong to magnoliids, and Ginkgo biloba. The name eudicots is used in the APG system, of 1998 and it is applied to a clade, a monophyletic group, which includes most of the dicots. The eudicots can be divided into two groups, the basal eudicots and the core eudicots, basal eudicot is an informal name for a paraphyletic group. The core eudicots are a monophyletic group, a 2010 study suggested the core eudicots can be divided into two clades, Gunnerales and a clade called Pentapetalae, comprising all the remaining core eudicots
Eudicots
–
Eudicots Temporal range:
Early Cretaceous - recent
Eudicots
–
Arabis pollen has three colpi.
25.
Dicotyledon
–
The dicotyledons, also known as dicots, were one of the two groups into which all the flowering plants or angiosperms were formerly divided. The name refers to one of the characteristics of the group. There are around 200,000 species within this group, the other group of flowering plants were called monocotyledons or monocots, typically having one cotyledon. Historically, these two formed the two divisions of the flowering plants. Rather, a number of lineages, such as the magnoliids and groups now known as the basal angiosperms. The traditional dicots are thus a paraphyletic group, the largest clade of the dicotyledons are known as the eudicots. They are distinguished from all other flowering plants by the structure of their pollen, aside from cotyledon number, other broad differences have been noted between monocots and dicots, although these have proven to be differences primarily between monocots and eudicots. Many early-diverging dicot groups have monocot characteristics such as scattered vascular bundles, trimerous flowers, in addition, some monocots have dicot characteristics such as reticulated leaf veins. Traditionally the dicots have been called the Dicotyledones, at any rank, if treated as a class, as in the Cronquist system, they could be called the Magnoliopsida after the type genus Magnolia. In some schemes, the eudicots were treated as a separate class, the remaining dicots may be kept in a single paraphyletic class, called Magnoliopsida, or further divided. Some botanists prefer to retain the dicotyledons as a class, arguing its practicality. The following lists show the orders in the APG III system traditionally called dicots, together with the older Cronquist system
Dicotyledon
–
Lamium album (white dead nettle)
Dicotyledon
–
Young
castor oil plant showing its prominent two embryonic leaves (
cotyledons), that differ from the adult leaves.
26.
Monocotyledon
–
Monocotyledons, commonly referred to as monocots, are flowering plants whose seeds typically contain only one embryonic leaf, or cotyledon. However, molecular research has shown that while the monocots form a monophyletic group or clade. Monocots have almost always recognized as a group, but with various taxonomic ranks. The APG III system of 2009 recognises a clade called monocots, the monocots include about 60,000 species. The largest family in this group by number of species are the orchids, about half as many species belong to the true grasses, which are economically the most important family of monocots. In agriculture the majority of the biomass produced comes from monocots and these include not only major grains, but also forage grasses, sugar cane, and the bamboos. Other economically important monocot crops include various palms, bananas, gingers and their relatives, turmeric and cardamom, asparagus and the onions and garlic family. Additionally most of the bulbs, plants cultivated for their blooms, such as lilies, daffodils, irises, amaryllis, cannas, bluebells. The monocots or monocotyledons have, as the name implies, a single cotyledon, or embryonic leaf, from a diagnostic point of view the number of cotyledons is neither a particularly useful characteristic, nor is it completely reliable. Nevertheless, monocots are sufficiently distinctive that there has rarely been disagreement as to membership of this group, however, morphological features that reliably characterise major clades are rare. Thus monocots are distinguishable from other angiosperms both in terms of their uniformity and diversity, although largely herbaceous, some arboraceous monocots reach great height, length and mass. The latter include agaves, palms, pandans, and bamboos and this creates challenges in water transport that monocots deal with in various ways. Some such as species of Yucca develop anomalous secondary growth, while palm trees, the axis undergoes primary thickening, that progresses from internode to internode, resulting in a typical inverted conical shape of the basal primary axis. The limited conductivity also contributes to limited branching of the stems, despite these limitations a wide variety of adaptive growth forms has resulted from epiphytic orchids and bromeliads to submarine Alismatales and mycotrophic Burmanniaceae and Triuridaceae. Other monocots, particularly Poales have adopted a life form. Leaves The cotyledon, the primordial Angiosperm leaf consists of a proximal leaf base or hypophyll, in moncots the hypophyll tends to be the dominant part in contrast to other angiosperms. Mature monocot leaves are narrow and linear, forming a sheathing around the stem at its base. There is usually only one leaf per node because the leaf base encompasses more than half the circumference, the evolution of this monocot characteristic has been attributed to developmental differences in early zonal differentiation rather than meristem activity
Monocotyledon
Monocotyledon
–
Comparison of a monocot and dicot sprouting. Note that the visible part of the monocot plant (left) is actually the first true leaf produced from the
meristem; the cotyledon itself remains within the seed.
Monocotyledon
–
Allium crenulatum, an onion, with a typical monocot
perianth and parallel leaf venation
Monocotyledon
–
Slice of onion, showing parallel veins in cross section
27.
Symmetry in biology
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Symmetry in biology is the balanced distribution of duplicate body parts or shapes within the body of an organism. In nature and biology, symmetry is always approximate, for example plant leaves, while considered symmetrical, symmetry creates a class of patterns in nature, where the near-repetition of the pattern element is by reflection or rotation. The body plans of most multicellular organisms exhibit some form of symmetry, whether radial, bilateral, a small minority, notably among the sponges, exhibit no symmetry. Radially symmetric organisms resemble a pie where several cutting planes produce roughly identical pieces, such an organism exhibits no left or right sides. They have a top and a surface only. Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish. Animals in the phyla cnidaria and echinodermata are radially symmetric, although many sea anemones and some corals have bilateral symmetry defined by a single structure, many flowers are radially symmetric or actinomorphic. Roughly identical flower parts – petals, sepals, and stamens occur at intervals around the axis of the flower. Many viruses have radial symmetries, their coats being composed of a small number of protein molecules arranged in a regular pattern to form polyhedrons, spheres. Tetramerism is a variant of radial symmetry found in jellyfish, which have four canals in an otherwise radial body plan, pentamerism, another variant of radial symmetry, means the organism is in five parts around a central axis, 72° apart. Among animals, only the echinoderms such as sea stars, sea urchins, being bilaterian animals, however, they initially develop with mirror symmetry as larvae, then gain pentaradial symmetry later. Flowering plants show fivefold symmetry in many flowers and in various fruits and this is well seen in the arrangement of the five carpels in an apple cut transversely. Hexamerism is found in the corals and sea anemones which are divided into two based on their symmetry. The most common corals in the subclass Hexacorallia have a body plan, their polyps have sixfold internal symmetry. Octamerism is found in corals of the subclass Octocorallia and these have polyps with eight tentacles and octameric radial symmetry. The octopus, however, has symmetry, despite its eight arms. Spherical symmetry occurs in an if it is able to be cut into two identical halves through any cut that runs through the organisms center. Organisms which show approximate spherical symmetry include the green alga Volvox
Symmetry in biology
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A selection of animals showing the range of possible symmetries, including both radial and bilateral
body plans.
Symmetry in biology
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These sea anemones have been painted to emphasize their radial symmetry. (
Plate from
Ernst Haeckel 's
Kunstformen der Natur).
Symmetry in biology
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Lilium bulbiferum displays typical
floral symmetry with repeated parts arranged around the axis of the flower.
Symmetry in biology
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Gastroenteritis viruses have radial symmetry, being
icosahedral: A
rotavirus, B
adenovirus, C
norovirus, D
astrovirus.
28.
Floral symmetry
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Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts. Uncommonly, flowers may have no axis of symmetry at all, most flowers are actinomorphic, meaning they can be divided into 3 or more identical sectors which are related to each other by rotation about the centre of the flower. Typically, each sector might contain one tepal or one petal and one sepal, actinomorphic flowers are also called radially symmetrical or regular flowers. Other examples of flowers are the lily and the buttercup. Zygomorphic flowers can be divided by only a plane into two mirror-image halves, much like a yoke or a persons face. Examples are orchids and the flowers of most members of the Lamiales, some authors prefer the term monosymmetry or bilateral symmetry. A few plant species have flowers lacking any symmetry, and therefore having a handedness, examples are Valeriana officinalis and Canna indica. Actinomorphic flowers are a basal angiosperm character, zygomorphic flowers are a character that has evolved many times. Peloria or a peloric flower refers to an aberration in which a plant that normally produces zygomorphic flowers produces actinomorphic flowers instead and this aberration can be developmental, or it can have a genetic basis, the CYCLOIDEA gene controls floral symmetry. Peloric Antirrhinum plants have produced by knocking out this gene. Many modern cultivars of Sinningia speciosa have been bred to have peloric flowers as they are larger and showier than the normally zygomorphic flowers of this species, charles Darwin explored peloria in Antirrhinum while researching the inheritance of floral characteristics for his The Variation of Animals and Plants under Domestication. Later research, using Digitalis purpurea, showed that his results were largely in line with Mendelian theory. If we consider only those flowers which consist in a flower, rather than a flower head or inflorescence. Monocots are identifiable by their trimerous petals, thus often have rotational symmetry of order 3. If the flower also has 3 lines of symmetry the group it belongs to is the dihedral group D3. If not, then it belongs to the cyclic group C3, eudicots with tetramerous or pentamerous petals may have rotational symmetry of order 4 or 5. Again, whether they also have mirror planes decides whether they belong to dihedral or cyclic groups and it must be remembered however, that flower symmetry is rarely perfect in the way that geometric symmetry is. The general layout of a flower belongs to the symmetry groups
Floral symmetry
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[Left] Normal
Streptocarpus flower (
zygomorphic or mirror-symmetric), and [right]
peloric (radially symmetric) flower on the same plant
Floral symmetry
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Wurmbea stricta, its
tepals in actinomorphic arrangement
Floral symmetry
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Satyrium carneum. Ground orchid with typical zygomorphic floral anatomy
Floral symmetry
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Digitalis purpurea (common foxglove) displaying an aberrant peloric terminal flower and normal zygomorphic flowers
29.
Orchid
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The Orchidaceae are a diverse and widespread family of flowering plants, with blooms that are often colourful and often fragrant, commonly known as the orchid family. Along with the Asteraceae, they are one of the two largest families of flowering plants, the Orchidaceae have about 28,000 currently accepted species, distributed in about 763 genera. The determination of which family is larger is still under debate, regardless, the number of orchid species nearly equals the number of bony fishes and is more than twice the number of bird species, and about four times the number of mammal species. The family also encompasses about 6–11% of all seed plants, the largest genera are Bulbophyllum, Epidendrum, Dendrobium and Pleurothallis. The family also includes Vanilla, Orchis, and many cultivated plants such as Phalaenopsis. Moreover, since the introduction of species into cultivation in the 19th century, horticulturists have produced more than 100,000 hybrids. Orchids are easily distinguished from plants, as they share some very evident, shared derived characteristics. Among these are, bilateral symmetry of the flower, many flowers, a nearly always highly modified petal, fused stamens and carpels. All orchids are perennial herbs that lack any permanent woody structure and they can grow according to two patterns, Monopodial, The stem grows from a single bud, leaves are added from the apex each year and the stem grows longer accordingly. The stem of orchids with a monopodial growth can reach several metres in length, as in Vanda, Sympodial, Sympodial orchids have a front and a back. The plant produces a series of adjacent shoots which grow to a size, bloom. Sympodial orchids grow laterally rather than vertically, following the surface of their support, the growth continues by development of new leads, with their own leaves and roots, sprouting from or next to those of the previous year, as in Cattleya. While a new lead is developing, the rhizome may start its growth again from a so-called eye, Sympodial orchids may have visible pseudobulbs joined by a rhizome, which creeps along the top or just beneath the soil. Terrestrial orchids may be rhizomatous or form corms or tubers, the root caps of terrestrial orchids are smooth and white. Some sympodial terrestrial orchids, such as Orchis and Ophrys, have two subterranean tuberous roots, one is used as a food reserve for wintry periods, and provides for the development of the other one, from which visible growth develops. In warm and constantly humid climates, many terrestrial orchids do not need pseudobulbs, epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis and it is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, the cells of the root epidermis grow at a right angle to the axis of the root to allow them to get a firm grasp on their support
Orchid
Orchid
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"Orchid" redirects here. For other uses, see
Orchid (disambiguation).
Orchid
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Anacamptis lactea showing the two tubers
Orchid
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The pseudobulb of Prosthechea fragrans
30.
Fabaceae
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The Fabaceae, Leguminosae or Papilionaceae, commonly known as the legume, pea, or bean family, are a large and economically important family of flowering plants. It includes trees, shrubs, and perennial or annual herbaceous plants, the five largest of the genera are Astragalus, Acacia, Indigofera, Crotalaria and Mimosa, which constitute about a quarter of all legume species. The ca.19,000 known legume species amount to about 7% of flowering plant species, Fabaceae is the most common family found in tropical rainforests and in dry forests in the Americas and Africa. Recent molecular and morphological evidence supports the fact that the Fabaceae is a monophyletic family. These studies confirm that the Fabaceae are a group that is closely related to the Polygalaceae, Surianaceae and Quillajaceae families. Along with the cereals, some fruits and tropical roots a number of Leguminosae have been a human food for millennia. A number of species are also weedy pests in different parts of the world, including, Cytisus scoparius, Robinia pseudoacacia, Ulex europaeus, Pueraria lobata, the name Fabaceae comes from the defunct genus Faba, now included in Vicia. The term faba comes from Latin, and appears to simply mean bean, Leguminosae is an older name still considered valid, and refers to the fruit of these plants, which are called legumes. Fabaceae range in habit from giant trees to small annual herbs, plants have indeterminate inflorescences, which are sometimes reduced to a single flower. The flowers have a short hypanthium and a single carpel with a short gynophore, the Leguminosae have a wide variety of growth forms including trees, shrubs or herbaceous plants or even vines or lianas. The herbaceous plants can be annuals, biennials or perennials, without basal or terminal leaf aggregations and they are upright plants, epiphytes or vines. The latter support themselves by means of shoots that twist around a support or through cauline or foliar tendrils, plants can be heliophytes, mesophytes or xerophytes. The leaves are alternate and compound. Most often they are even- or odd-pinnately compound, often trifoliate and rarely palmately compound, in the Mimosoideae and they always have stipules, which can be leaf-like, thorn-like or be rather inconspicuous. Leaf margins are entire or, occasionally, serrate, both the leaves and the leaflets often have wrinkled pulvini to permit nastic movements. In some species, leaflets have evolved into tendrils, many species have leaves with structures that attract ants that protect the plant from herbivore insects. Extrafloral nectaries are common among the Mimosoideae and the Caesalpinioideae, and are found in some Faboideae. In some Acacia, the modified hollow stipules are inhabited by ants and are known as domatia, many Fabaceae host bacteria in their roots within structures called root nodules
Fabaceae
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Fabaceae Temporal range:
Palaeocene –
Recent
Fabaceae
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The fruit of
Gymnocladus dioicus
Fabaceae
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A flower of
Wisteria sinensis, Faboideae. Two petals have been removed to show stamens and pistil
Fabaceae
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Legume of
Vicia angustifolia
Chisholm, Hugh, ed. (1911). "Flower". Encyclopædia Britannica. 10: Evangelical Church – Francis Joseph I. (11th ed.). Cambridge University Press.
Chisholm, Hugh, ed. (1911). 
