Antoine Laurent de Jussieu
Antoine Laurent de Jussieu was a French botanist, notable as the first to publish a natural classification of flowering plants. His classification was based on an extended unpublished work by his uncle, the botanist Bernard de Jussieu. Jussieu was born in Lyon, he went to Paris to study medicine, graduating in 1770. He was professor of botany at the Jardin des Plantes from 1770 to 1826, his son Adrien-Henri became a botanist. In his study of flowering plants, Genera plantarum, Jussieu adopted a methodology based on the use of multiple characters to define groups, an idea derived from naturalist Michel Adanson; this was a significant improvement over the "artificial" system of Linnaeus, whose most popular work classified plants into classes and orders based on the number of stamens and pistils. Jussieu did keep Linnaeus' binomial nomenclature, resulting in a work, far-reaching in its impact. Morton's 1981 History of botanical science counts 76 of Jussieu's families conserved in the ICBN, versus just 11 for Linnaeus, for instance.
Writing of the natural system, Sydney Howard Vines remarked "The glory of this crowning achievement belongs to Jussieu: he was the capable man who appeared at the psychological moment, it is the men that so appear who have made, will continue to make, all the great generalisations of science." In 1788, he was elected a foreign member of the Royal Swedish Academy of Sciences. He was a member of Les Neuf Sœurs; the system of suprageneric nomenclature in botany is dated to 4 Aug 1789 with the publication of the Genera Plantarum. De Jussieu system
A shrub or bush is a small- to medium-sized woody plant. Unlike herbaceous plants, shrubs have persistent woody, they are distinguished from trees by their multiple stems and shorter height, are under 6 m tall. Plants of many species may grow either depending on their growing conditions. Small, low shrubs less than 2 m tall, such as lavender and most small garden varieties of rose, are termed "subshrubs". An area of cultivated shrubs in a park or a garden is known as a shrubbery; when clipped as topiary, suitable species or varieties of shrubs develop dense foliage and many small leafy branches growing close together. Many shrubs respond well to renewal pruning, in which hard cutting back to a "stool" results in long new stems known as "canes". Other shrubs respond better to selective pruning to reveal their character. Shrubs in common garden practice are considered broad-leaved plants, though some smaller conifers such as mountain pine and common juniper are shrubby in structure. Species that grow into a shrubby habit may be either evergreen.
In botany and ecology, a shrub is more used to describe the particular physical structural or plant life-form of woody plants which are less than 8 metres high and have many stems arising at or near the base. For example, a descriptive system adopted in Australia is based on structural characteristics based on life-form, plus the height and amount of foliage cover of the tallest layer or dominant species. For shrubs 2–8 metres high the following structural forms are categorized: dense foliage cover — closed-shrub mid-dense foliage cover — open-shrub sparse foliage cover — tall shrubland sparse foliage cover — tall open shrublandFor shrubs less than 2 metres high the following structural forms are categorized: dense foliage cover — closed-heath or closed low shrubland— mid-dense foliage cover — open-heath or mid-dense low shrubland— sparse foliage cover — low shrubland sparse foliage cover — low open shrubland Those marked with * can develop into tree form
Boronia is a genus of about 160 species of flowering plants in the citrus family Rutaceae, most are endemic in Australia with a few species in New Caledonia, which were placed in the genus Boronella. They occur in all Australian states but the genus is under review and a number of species are yet to be described or the description published. Boronias are similar to familiar plants in the genera Zieria and Correa but can be distinguished from them by the number of petals or stamens; some species are popular garden plants. Plants in the genus Boronia are nearly always shrubs although a small number occur as herbs or as small trees; the leaves are arranged in opposite pairs and may be simple leaves or compound leaves with up to nineteen or more leaflets, in either a pinnate or bipinnate arrangement. The flowers are arranged in groups in the leaf axils or on the ends of the branches and have both male and female parts. There are four separate sepals four separate petals and eight stamens. There are four carpels with their styles fused and there are two ovules in each carpel.
The genus Boronia was first formally described in 1798 by James Edward Smith and the description was published in Tracts Relating to Natural History. The name Boronia honours Francesco Borone, Italian naturalist and plant collector, who assisted John Sibthorp in Greece and Turkey, Adam Afzelius in Sierra Leone and James Edward Smith during his European tour in 1787. Boronia, an outer suburb of Melbourne in Australia was named after a boronia found growing in the area. Boronias are found in all states and mainland territories of Australia and grow in open forests or woodlands, only in rainforests or arid areas. Boronias B. megastigma, are known for their perfumed flowers. Most are regarded as desirable specimens in the garden, many are difficult to grow in cultivation. All species require excellent part shade. List of Boronia species
A lime is a citrus fruit, round, green in color, 3–6 centimetres in diameter, contains acidic juice vesicles. There are several species of citrus trees whose fruits are called limes, including the Key lime, Persian lime, kaffir lime, desert lime. Limes are a rich source of vitamin C, sour and are used to accent the flavours of foods and beverages, they are grown year-round. Plants with fruit called; the difficulty in identifying which species of fruit are called lime in different parts of the English-speaking world is increased by the botanical complexity of the citrus genus itself, to which the majority of limes belong. Species of this genus hybridise and it is only that genetic studies have started to throw light on the structure of the genus; the majority of cultivated species are in reality hybrids, produced from the citron, the mandarin orange, the pomelo and in particular with many lime varieties, the micrantha. Australian limes Australian desert lime Australian finger lime Australian lime Blood lime Kaffir lime.
Key lime is one of three most produced limes globally. Musk lime, a kumquat × mandarin hybrid Persian lime a key lime × lemon hybrid, is the single most produced lime globally, with Mexico being the largest producer. Rangpur lime, a mandarin orange × citron hybrid Spanish lime. Although the precise origin is uncertain, wild limes are believed to have first grown in Indonesia or Southeast Asia, were transported to the Mediterranean region and north Africa around 1000 CE. To prevent scurvy during the 19th century, British sailors were issued a daily allowance of citrus, such as lemon, switched to lime; the use of citrus was a guarded military secret, as scurvy was a common scourge of various national navies, the ability to remain at sea for lengthy periods without contracting the disorder was a huge benefit for the military. The British sailor thus acquired the nickname, "Limey" because of their usage of limes. In 2016, global production of lemons and limes was 17.3 million tonnes, led by India with 17% of the world total.
Mexico and China were other major producers. Limes have higher contents of acids than lemons do. Lime juice may be squeezed from fresh limes, or purchased in bottles in both unsweetened and sweetened varieties. Lime juice is used to make limeade, as an ingredient in many cocktails. Lime pickles are an integral part of Indian cuisine. South Indian cuisine is based on lime. In cooking, lime is valued both for the floral aroma of its zest, it is a common ingredient in authentic Mexican and Thai dishes. Lime soup is a traditional dish from the Mexican state of Yucatan, it is used for its pickling properties in ceviche. Some guacamole recipes call for lime juice; the use of dried limes as a flavouring is typical of Persian cuisine and Iraqi cuisine, as well as in Persian Gulf-style baharat. Lime is an ingredient of many cuisines from India, many varieties of pickles are made, e.g. sweetened lime pickle, salted pickle, lime chutney. Key lime gives the character flavoring to the American dessert known as Key lime pie.
In Australia, desert lime is used for making marmalade. Lime is an ingredient in several highball cocktails based on gin, such as gin and tonic, the gimlet and the Rickey. Freshly squeezed lime juice is considered a key ingredient in margaritas, although sometimes lemon juice is substituted. Lime extracts and lime essential oils are used in perfumes, cleaning products, aromatherapy. Raw limes are 10 % carbohydrates and less than 1 % each of fat and protein. Only vitamin C content at 35% of the Daily Value per 100 g serving is significant for nutrition, with other nutrients present in low DV amounts. Lime juice contains less citric acid than lemon juice, nearly twice the citric acid of grapefruit juice, about five times the amount of citric acid found in orange juice. Lime pulp and peel contain diverse phytochemicals, including polyphenols and terpenes, many of which are under basic research for their potential properties in humans. Contact with lime peel or lime juice followed by exposure to ultraviolet light may lead to phytophotodermatitis, sometimes called margarita photodermatitis or lime disease.
Bartenders handling limes and other citrus fruits while preparing cocktails may develop phytophotodermatitis. A class of organic chemical compounds ca
Plants are multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Plants were treated as one of two kingdoms including all living things that were not animals, all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants and other gymnosperms and their allies, liverworts and the green algae, but excludes the red and brown algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria, their chloroplasts contain b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is common.
There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants. Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecosystems on land. Plants that produce grain and vegetables form humankind's basic foods, have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs; the scientific study of plants is known as a branch of biology. All living things were traditionally placed into one of two groups and animals; this classification may date from Aristotle, who made the distincton between plants, which do not move, animals, which are mobile to catch their food. Much when Linnaeus created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia and Animalia. Since it has become clear that the plant kingdom as defined included several unrelated groups, the fungi and several groups of algae were removed to new kingdoms.
However, these organisms are still considered plants in popular contexts. The term "plant" implies the possession of the following traits multicellularity, possession of cell walls containing cellulose and the ability to carry out photosynthesis with primary chloroplasts; when the name Plantae or plant is applied to a specific group of organisms or taxon, it refers to one of four concepts. From least to most inclusive, these four groupings are: Another way of looking at the relationships between the different groups that have been called "plants" is through a cladogram, which shows their evolutionary relationships; these are not yet settled, but one accepted relationship between the three groups described above is shown below. Those which have been called "plants" are in bold; the way in which the groups of green algae are combined and named varies between authors. Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom.
The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the green algae, red algae and brown algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, they are no longer classified as plants as defined here; the Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions, the green plants have the following features in common, they undergo closed mitosis without centrioles, have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria. Two additional groups, the Rhodophyta and Glaucophyta have primary chloroplasts that appear to be derived directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in the pigments which are used in photosynthesis and so are different in colour.
These groups differ from green plants in that the storage polysaccharide is floridean starch and is stored in the cytoplasm rather than in the plastids. They appear to have had a common origin with Viridiplantae and the three groups form the clade Archaeplastida, whose name implies that their chloroplasts were derived from a single ancient endosymbiotic event; this is the broadest modern definition of the term'plant'. In contrast, most other algae not only have different pigments but have chloroplasts with three or four surrounding membranes, they are not close relatives of the Archaeplastida having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in the broadest modern definition of the plant kingdom, although they were in the past; the green plants or Viridiplantae were traditionally divided into the green algae (including
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants. The biological function of a flower is to effect reproduction by providing a mechanism for the union of sperm with eggs. Flowers may allow selfing; some flowers produce diaspores without fertilization. Flowers are the site where gametophytes develop. Many flowers have evolved to be attractive to animals, so as to cause them to be vectors for the transfer of pollen. After fertilization, the ovary of the flower develops into fruit containing seeds. In addition to facilitating the reproduction of flowering plants, flowers have long been admired and used by humans to bring beauty to their environment, as objects of romance, religion, medicine and as a source of food; the essential parts of a flower can be considered in two parts: the vegetative part, consisting of petals and associated structures in the perianth, the reproductive or sexual parts. A stereotypical flower consists of four kinds of structures attached to the tip of a short stalk.
Each of these kinds of parts is arranged in a whorl on the receptacle. The four main whorls are as follows: Collectively the calyx and corolla form the perianth. Calyx: the outermost whorl consisting of units called sepals. Corolla: the next whorl toward the apex, composed of units called petals, which are thin and colored to attract animals that help the process of pollination. Androecium: the next whorl, consisting of units called stamens. Stamens consist of two parts: a stalk called a filament, topped by an anther where pollen is produced by meiosis and dispersed. Gynoecium: the innermost whorl of a flower, consisting of one or more units called carpels; the carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. Ovules are megasporangia and they in turn produce megaspores by meiosis which develop into female gametophytes; these give rise to egg cells. The gynoecium of a flower is described using an alternative terminology wherein the structure one sees in the innermost whorl is called a pistil.
A pistil may consist of a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen; the supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma. The relationship to the gynoecium on the receptacle is described as hypogynous, perigynous, or epigynous. Although the arrangement described above is considered "typical", plant species show a wide variation in floral structure; these modifications have significance in the evolution of flowering plants and are used extensively by botanists to establish relationships among plant species. The four main parts of a flower are defined by their positions on the receptacle and not by their function. Many flowers lack some parts or parts may be modified into other functions and/or look like what is another part. In some families, like Ranunculaceae, the petals are reduced and in many species the sepals are colorful and petal-like. Other flowers have modified stamens.
Flowers show great variation and plant scientists describe this variation in a systematic way to identify and distinguish species. Specific terminology is used to describe their parts. Many flower parts are fused together; when petals are fused into a tube or ring that falls away as a single unit, they are sympetalous. Connate petals may have distinctive regions: the cylindrical base is the tube, the expanding region is the throat and the flaring outer region is the limb. A sympetalous flower, with bilateral symmetry with an upper and lower lip, is bilabiate. Flowers with connate petals or sepals may have various shaped corolla or calyx, including campanulate, tubular, salverform or rotate. Referring to "fusion," as it is done, appears questionable because at least some of the processes involved may be non-fusion processes. For example, the addition of intercalary growth at or below the base of the primordia of floral appendages such as sepals, petals and carpels may lead to a common base, not the result of fusion.
Many flowers have a symmetry. When the perianth is bisected through the central axis from any point and symmetrical halves are produced, the flower is said to be actinomorphic or regular, e.g. rose or trillium. This is an example of radial symmetry; when flowers are bisected and produce only one line that produces symmetrical halves, the flower is said to be irregular or zygomorphic, e.g. snapdragon or most orchids. Flowers may be directly attached to the plant at their base; the stem or stalk subtending a flower is called a peduncle. If a peduncle supports more than o
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". A leaf is a thin, dorsiventrally flattened organ borne above ground and specialized for photosynthesis. In most leaves, the primary photosynthetic tissue, the palisade mesophyll, is located on the upper side of the blade or lamina of the leaf but in some species, including the mature foliage of Eucalyptus, palisade mesophyll is present on both sides and the leaves are said to be isobilateral. Most leaves have distinct upper surface and lower surface that differ in colour, the number of stomata, the amount and structure of epicuticular wax and other features. Leaves can have many different shapes and textures; the broad, flat leaves with complex venation of flowering plants are known as megaphylls and the species that bear them, the majority, as broad-leaved or megaphyllous plants. In the clubmosses, with different evolutionary origins, the leaves are simple and are known as microphylls.
Some leaves, such as bulb scales, are not above ground. In many aquatic species the leaves are submerged in water. Succulent plants have thick juicy leaves, but some leaves are without major photosynthetic function and may be dead at maturity, as in some cataphylls and spines. Furthermore, several kinds of leaf-like structures found in vascular plants are not homologous with them. Examples include flattened plant stems called phylloclades and cladodes, flattened leaf stems called phyllodes which differ from leaves both in their structure and origin; some structures of non-vascular plants function much like leaves. Examples include the phyllids of liverworts. Leaves are the most important organs of most vascular plants. Green plants are autotrophic, meaning that they do not obtain food from other living things but instead create their own food by photosynthesis, they capture the energy in sunlight and use it to make simple sugars, such as glucose and sucrose, from carbon dioxide and water. The sugars are stored as starch, further processed by chemical synthesis into more complex organic molecules such as proteins or cellulose, the basic structural material in plant cell walls, or metabolised by cellular respiration to provide chemical energy to run cellular processes.
The leaves draw water from the ground in the transpiration stream through a vascular conducting system known as xylem and obtain carbon dioxide from the atmosphere by diffusion through openings called stomata in the outer covering layer of the leaf, while leaves are orientated to maximise their exposure to sunlight. Once sugar has been synthesized, it needs to be transported to areas of active growth such as the plant shoots and roots. Vascular plants transport sucrose in a special tissue called the phloem; the phloem and xylem are parallel to each other but the transport of materials is in opposite directions. Within the leaf these vascular systems branch to form veins which supply as much of the leaf as possible, ensuring that cells carrying out photosynthesis are close to the transportation system. Leaves are broad and thin, thereby maximising the surface area directly exposed to light and enabling the light to penetrate the tissues and reach the chloroplasts, thus promoting photosynthesis.
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 and eucalyptss; the flat, or laminar, shape maximises thermal contact with the surrounding air, promoting cooling. Functionally, in addition to carrying out photosynthesis, the leaf is the principal site of transpiration, providing the energy required to draw the transpiration stream up from the roots, guttation. Many gymnosperms have thin needle-like or scale-like leaves that can be advantageous in cold climates with frequent snow and frost; these are interpreted as reduced from megaphyllous leaves of their Devonian ancestors. Some leaf forms are adapted to modulate the amount of light they absorb to avoid or mitigate excessive heat, ultraviolet damage, or desiccation, or to sacrifice light-absorption efficiency in favour of protection from herbivory.
For xerophytes the major constraint drought. 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. Leaves function to store chemical energy and water and may become specialised organs serving other functions, such as tendrils of peas and other legumes, the protective spines of cacti and the insect traps in carnivorous plants such as Nepenthes and Sarracenia. Leaves are the fundamental structural units from which cones are constructed in gymnosperms and from which flowers are constructed in flowering plants; the internal organisation of most kinds of leaves has evolved to maximise exposure of the photosynthetic organelles, the chloroplasts, to light and to increase the absorption of carbon dioxide while at the same time controlling water loss. Their surfaces are waterproofed by the plant cuticle and gas exchange between the mesophyll cells and the atmosphere is controlled by minute openings called stomata which open or close to regulate the rate exchange of carbon dioxide and water vapour into