Paleobotany
Paleobotany spelled as palaeobotany, is the branch of paleontology or paleobiology dealing with the recovery and identification of plant remains from geological contexts, their use for the biological reconstruction of past environments, both the evolutionary history of plants, with a bearing upon the evolution of life in general. A synonym is paleophytology. Paleobotany includes the study of terrestrial plant fossils, as well as the study of prehistoric marine photoautotrophs, such as photosynthetic algae, seaweeds or kelp. A related field is palynology, the study of fossilized and extant spores and pollen. Paleobotany is important in the reconstruction of ancient ecological systems and climate, known as paleoecology and paleoclimatology respectively. Paleobotany has become important to the field of archaeology for the use of phytoliths in relative dating and in paleoethnobotany; the emergence of paleobotany as a scientific discipline can be seen in the early 19th century in the works of the German palaeontologist Ernst Friedrich von Schlotheim, the Czech nobleman and scholar Kaspar Maria von Sternberg, the French botanist Adolphe-Théodore Brongniart.
Macroscopic remains of true vascular plants are first found in the fossil record during the Silurian Period of the Paleozoic era. Some dispersed, fragmentary fossils of disputed affinity spores and cuticles, have been found in rocks from the Ordovician Period in Oman, are thought to derive from liverwort- or moss-grade fossil plants. An important early land plant fossil locality is the Rhynie Chert, found outside the village of Rhynie in Scotland; the Rhynie chert is an Early Devonian sinter deposit composed of silica. It is exceptional due to its preservation of several different clades of plants, from mosses and lycopods to more unusual, problematic forms. Many fossil animals, including arthropods and arachnids, are found in the Rhynie Chert, it offers a unique window on the history of early terrestrial life. Plant-derived macrofossils become abundant in the Late Devonian and include tree trunks and roots; the earliest tree was thought to be Archaeopteris, which bears simple, fern-like leaves spirally arranged on branches atop a conifer-like trunk, though it is now known to be the discovered Wattieza.
Widespread coal swamp deposits across North America and Europe during the Carboniferous Period contain a wealth of fossils containing arborescent lycopods up to 30 meters tall, abundant seed plants, such as conifers and seed ferns, countless smaller, herbaceous plants. Angiosperms evolved during the Mesozoic, flowering plant pollen and leaves first appear during the Early Cretaceous 130 million years ago. A plant fossil is any preserved part of a plant; such fossils may be prehistoric impressions that are many millions of years old, or bits of charcoal that are only a few hundred years old. Prehistoric plants are various groups of plants. Plant fossils can be preserved in a variety of ways, each of which can give different types of information about the original parent plant; these modes of preservation are discussed in the general pages on fossils but may be summarised in a palaeobotanical context as follows. Adpressions; these are the most found type of plant fossil. They provide good morphological detail of dorsiventral plant parts such as leaves.
If the cuticle is preserved, they can yield fine anatomical detail of the epidermis. Little other detail of cellular anatomy is preserved. Petrifactions; these provide fine detail of the cell anatomy of the plant tissue. Morphological detail can be determined by serial sectioning, but this is both time consuming and difficult. Moulds and casts; these only tend to preserve the more robust plant parts such as seeds or woody stems. They can provide information about the three-dimensional form of the plant, in the case of casts of tree stumps can provide evidence of the density of the original vegetation. However, they preserve any fine morphological detail or cell anatomy. A subset of such fossils are pith casts, where the centre of a stem is either hollow or has delicate pith. After death, sediment forms a cast of the central cavity of the stem; the best known examples of pith casts are in cordaites. Authigenic mineralisations; these can provide fine, three-dimensional morphological detail, have proved important in the study of reproductive structures that can be distorted in adpressions.
However, as they are formed in mineral nodules, such fossils can be of large size. Fusain. Fire destroys plant tissue but sometimes charcoalified remains can preserve fine morphological detail, lost in other modes of preservation. Fusain fossils are delicate and small, but because of their buoyancy can drift for long distances and can thus provide evidence of vegetation away from areas of sedimentation. Plant fossils always represent disarticulated parts of plants; those few examples of plant fossils that appear to be the remains of whole plants in fact are incomplete as the internal cellular tis
Botany
Botany called plant science, plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist; the term "botany" comes from the Ancient Greek word βοτάνη meaning "pasture", "grass", or "fodder". Traditionally, botany has included the study of fungi and algae by mycologists and phycologists with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists study 410,000 species of land plants of which some 391,000 species are vascular plants, 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and cultivate – edible and poisonous plants, making it one of the oldest branches of science. Medieval physic gardens attached to monasteries, contained plants of medical importance, they were forerunners of the first botanical gardens attached to universities, founded from the 1540s onwards.
One of the earliest was the Padua botanical garden. These gardens facilitated the academic study of plants. Efforts to catalogue and describe their collections were the beginnings of plant taxonomy, led in 1753 to the binomial system of Carl Linnaeus that remains in use to this day. In the 19th and 20th centuries, new techniques were developed for the study of plants, including methods of optical microscopy and live cell imaging, electron microscopy, analysis of chromosome number, plant chemistry and the structure and function of enzymes and other proteins. In the last two decades of the 20th century, botanists exploited the techniques of molecular genetic analysis, including genomics and proteomics and DNA sequences to classify plants more accurately. Modern botany is a broad, multidisciplinary subject with inputs from most other areas of science and technology. Research topics include the study of plant structure and differentiation, reproduction and primary metabolism, chemical products, diseases, evolutionary relationships and plant taxonomy.
Dominant themes in 21st century plant science are molecular genetics and epigenetics, which are the mechanisms and control of gene expression during differentiation of plant cells and tissues. Botanical research has diverse applications in providing staple foods, materials such as timber, rubber and drugs, in modern horticulture and forestry, plant propagation and genetic modification, in the synthesis of chemicals and raw materials for construction and energy production, in environmental management, the maintenance of biodiversity. Botany originated as the study and use of plants for their medicinal properties. Many records of the Holocene period date early botanical knowledge as far back as 10,000 years ago; this early unrecorded knowledge of plants was discovered in ancient sites of human occupation within Tennessee, which make up much of the Cherokee land today. The early recorded history of botany includes many ancient writings and plant classifications. Examples of early botanical works have been found in ancient texts from India dating back to before 1100 BC, in archaic Avestan writings, in works from China before it was unified in 221 BC.
Modern botany traces its roots back to Ancient Greece to Theophrastus, a student of Aristotle who invented and described many of its principles and is regarded in the scientific community as the "Father of Botany". His major works, Enquiry into Plants and On the Causes of Plants, constitute the most important contributions to botanical science until the Middle Ages seventeen centuries later. Another work from Ancient Greece that made an early impact on botany is De Materia Medica, a five-volume encyclopedia about herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides. De Materia Medica was read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya's Nabatean Agriculture, Abū Ḥanīfa Dīnawarī's the Book of Plants, Ibn Bassal's The Classification of Soils. In the early 13th century, Abu al-Abbas al-Nabati, Ibn al-Baitar wrote on botany in a systematic and scientific manner. In the mid-16th century, "botanical gardens" were founded in a number of Italian universities – the Padua botanical garden in 1545 is considered to be the first, still in its original location.
These gardens continued the practical value of earlier "physic gardens" associated with monasteries, in which plants were cultivated for medical use. They supported the growth of botany as an academic subject. Lectures were given about the plants grown in the gardens and their medical uses demonstrated. Botanical gardens came much to northern Europe. Throughout this period, botany remained subordinate to medicine. German physician Leonhart Fuchs was one of "the three German fathers of botany", along with theologian Otto Brunfels and physician Hieronymus Bock. Fuchs and Brunfels broke away from the tradition of copying earlier works to make original observations of their own. Bock created his own system of plant classification. Physician Valerius Cordus authored a botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium
Analogy
Analogy is a cognitive process of transferring information or meaning from a particular subject to another, or a linguistic expression corresponding to such a process. In a narrower sense, analogy is an inference or an argument from one particular to another particular, as opposed to deduction and abduction, in which at least one of the premises, or the conclusion, is general rather than particular in nature; the term analogy can refer to the relation between the source and the target themselves, a similarity, as in the biological notion of analogy. Analogy plays a significant role in problem solving, as well as decision making, perception, memory, invention, emotion, conceptualization and communication, it lies behind basic tasks such as the identification of places and people, for example, in face perception and facial recognition systems. It has been argued that analogy is "the core of cognition". Specific analogical language comprises exemplification, metaphors, similes and parables, but not metonymy.
Phrases like and so on, the like, as if, the word like rely on an analogical understanding by the receiver of a message including them. Analogy is important not only in ordinary language and common sense but in science, philosophy and the humanities; the concepts of association, correspondence and morphological homology, iconicity, metaphor and similarity are related to analogy. In cognitive linguistics, the notion of conceptual metaphor may be equivalent to that of analogy. Analogy is a basis for any comparative arguments as well as experiments whose results are transmitted to objects that have been not under examination. Analogy has been studied and discussed since classical antiquity by philosophers, scientists and lawyers; the last few decades have shown a renewed interest in analogy, most notably in cognitive science. With respect to the terms source and target there are two distinct traditions of usage: The logical and cultures and economics tradition speaks of an arrow, mapping, or morphism from what is the more complex domain or source to what is the less complex codomain or target, using all of these words in the sense of mathematical category theory.
The tradition in cognitive psychology, in literary theory, in specializations within philosophy outside of logic, speaks of a mapping from what is the more familiar area of experience, the source, to what is the more problematic area of experience, the target. In ancient Greek the word αναλογια meant proportionality, in the mathematical sense, it was indeed sometimes translated to Latin as proportio. From there analogy was understood as identity of relation between any two ordered pairs, whether of mathematical nature or not. Kant's Critique of Judgment held to this notion. Kant argued that there can be the same relation between two different objects; the same notion of analogy was used in the US-based SAT tests, that included "analogy questions" in the form "A is to B as C is to what?" For example, "Hand is to palm as foot is to ____?" These questions were given in the Aristotelian format: HAND: PALM:: FOOT: ____ While most competent English speakers will give the right answer to the analogy question, it is more difficult to identify and describe the exact relation that holds both between pairs such as hand and palm, between foot and sole.
This relation is not apparent in some lexical definitions of palm and sole, where the former is defined as the inner surface of the hand, the latter as the underside of the foot. Analogy and abstraction are different cognitive processes, analogy is an easier one; this analogy is not comparing all the properties between a hand and a foot, but rather comparing the relationship between a hand and its palm to a foot and its sole. While a hand and a foot have many dissimilarities, the analogy focuses on their similarity in having an inner surface. A computer algorithm has achieved human-level performance on multiple-choice analogy questions from the SAT test; the algorithm measures the similarity of relations between pairs of words by statistical analysis of a large collection of text. It answers SAT questions by selecting the choice with the highest relational similarity. Greek philosophers such as Plato and Aristotle used a wider notion of analogy, they saw analogy as a shared abstraction. Analogous objects did not share a relation, but an idea, a pattern, a regularity, an attribute, an effect or a philosophy.
These authors accepted that comparisons, metaphors and "images" could be used as arguments, sometimes they called them analogies. Analogies should make those abstractions easier to understand and give confidence to the ones using them; the Middle Age saw theorization of analogy. Roman lawyers had used analogical reasoning and the Greek word analogia. Medieval lawyers distinguished analogia legis and analogia iuris. In Islamic logic, analogical reasoning was used for the process of qiyas in Islamic sharia law and fiqh jurisprudence. In Christian theology, analogical arguments were accepted in order to explain the
History of botany
The history of botany examines the human effort to understand life on Earth by tracing the historical development of the discipline of botany—that part of natural science dealing with organisms traditionally treated as plants. Rudimentary botanical science began with empirically-based plant lore passed from generation to generation in the oral traditions of paleolithic hunter-gatherers; the first written records of plants were made in the Neolithic Revolution about 10,000 years ago as writing was developed in the settled agricultural communities where plants and animals were first domesticated. The first writings that show human curiosity about plants themselves, rather than the uses that could be made of them, appears in the teachings of Aristotle's student Theophrastus at the Lyceum in ancient Athens in about 350 BC. In Europe, this early botanical science was soon overshadowed by a medieval preoccupation with the medicinal properties of plants that lasted more than 1000 years. During this time, the medicinal works of classical antiquity were reproduced in manuscripts and books called herbals.
In China and the Arab world, the Greco-Roman work on medicinal plants was extended. In Europe the Renaissance of the 14th–17th centuries heralded a scientific revival during which botany emerged from natural history as an independent science, distinct from medicine and agriculture. Herbals were replaced by floras: books; the invention of the microscope stimulated the study of plant anatomy, the first designed experiments in plant physiology were performed. With the expansion of trade and exploration beyond Europe, the many new plants being discovered were subjected to an rigorous process of naming and classification. Progressively more sophisticated scientific technology has aided the development of contemporary botanical offshoots in the plant sciences, ranging from the applied fields of economic botany, to the detailed examination of the structure and function of plants and their interaction with the environment over many scales from the large-scale global significance of vegetation and plant communities through to the small scale of subjects like cell theory, molecular biology and plant biochemistry.
Botany and zoology are the core disciplines of biology whose history is associated with the natural sciences chemistry and geology. A distinction can be made between botanical science in a pure sense, as the study of plants themselves, botany as applied science, which studies the human use of plants. Early natural history divided pure botany into three main streams morphology-classification and physiology – that is, external form, internal structure, functional operation; the most obvious topics in applied botany are horticulture and agriculture although there are many others like weed science, plant pathology, pharmacognosy, economic botany and ethnobotany which lie outside modern courses in botany. Since the origin of botanical science there has been a progressive increase in the scope of the subject as technology has opened up new techniques and areas of study. Modern molecular systematics, for example, entails the principles and techniques of taxonomy, molecular biology, computer science and more.
Within botany there are a number of sub-disciplines that focus on particular plant groups, each with their own range of related studies. Included here are: phycology, pteridology and palaeobotany and their histories are treated elsewhere. To this list can be added mycology, the study of fungi, which were once treated as plants, but are now ranked as a unique kingdom. Nomadic hunter-gatherer societies passed on, by oral tradition, what they knew about the different kinds of plants that they used for food, poisons, for ceremonies and rituals etc; the uses of plants by these pre-literate societies influenced the way the plants were named and classified—their uses were embedded in folk-taxonomies, the way they were grouped according to use in everyday communication. The nomadic life-style was drastically changed when settled communities were established in about twelve centres around the world during the Neolithic Revolution which extended from about 10,000 to 2500 years ago depending on the region.
With these communities came the development of the technology and skills needed for the domestication of plants and animals and the emergence of the written word provided evidence for the passing of systematic knowledge and culture from one generation to the next. During the Neolithic Revolution plant knowledge increased most through the use of plants for food and medicine. All of today's staple foods were domesticated in prehistoric times as a gradual process of selection of higher-yielding varieties took place unknowingly, over hundreds to thousands of years. Legumes were cultivated on all continents but cereals made up most of the regular diet: rice in East Asia and barley in the Middle east, maize in Central and South America. By Greco-Roman times popular food plants of today, including grapes, apples and olives, were being listed as named varieties in early manuscripts. Botanical authority William Stearn has observed that "cultivated plants are mankind's most vital and precious heritage from remote antiquity".
It is from the Neolithic, in about 3000 BC, that we glimpse the first known illustrations of plants and read descript
Lilium
Lilium is a genus of herbaceous flowering plants growing from bulbs, all with large prominent flowers. Lilies are a group of flowering plants which are important in culture and literature in much of the world. Most species are native to the temperate northern hemisphere, though their range extends into the northern subtropics. Many other plants are not related to true lilies. Lilies are tall perennials ranging in height from 2–6 ft, they form naked or tunicless scaly underground bulbs which are their organs of perennation. In some North American species the base of the bulb develops into rhizomes, on which numerous small bulbs are found; some species develop stolons. Most bulbs are buried deep in the ground. Many species form stem-roots. With these, the bulb grows at some depth in the soil, each year the new stem puts out adventitious roots above the bulb as it emerges from the soil; these roots are in addition to the basal roots. The flowers are large fragrant, come in a wide range of colors including whites, oranges, pinks and purples.
Markings include spots and brush strokes. The plants are late spring- or summer-flowering. Flowers are borne in racemes or umbels at the tip of the stem, with six tepals spreading or reflexed, to give flowers varying from funnel shape to a "Turk's cap"; the tepals are free from each other, bear a nectary at the base of each flower. The ovary borne above the point of attachment of the anthers; the fruit is a three-celled capsule. Seeds ripen in late summer, they exhibit varying and sometimes complex germination patterns, many adapted to cool temperate climates. Most cool temperate species are deciduous and dormant in winter in their native environment, but a few species which distribute in hot summer and mild winter area lose leaves and remain short dormant in Summer or Autumn, sprout from Autumn to winter, forming dwarf stem bearing a basal rosette of leaves until, after they have received sufficient chilling, the stem begins to elongate in warming weather. The basic chromosome number is twelve.
Taxonomical division in sections follows the classical division of Comber, species acceptance follows the World Checklist of Selected Plant Families, the taxonomy of section Pseudolirium is from the Flora of North America, the taxonomy of Section Liriotypus is given in consideration of Resetnik et al. 2007, the taxonomy of Chinese species follows the Flora of China and the taxonomy of Section Sinomartagon follows Nishikawa et al. as does the taxonomy of Section Archelirion. The World Checklist of Selected Plant Families, as of January 2014, considers Nomocharis a separate genus in its own right, however some authorities consider Nomocharis to be embedded within Lilium, rather than treat it as a separate genus. There are seven sections: Martagon Pseudolirium Liriotypus Archelirion Sinomartagon Leucolirion DaurolirionFor a full list of accepted species with their native ranges, see List of Lilium species Some species included within this genus have now been placed in other genera; these genera include Cardiocrinum, Notholirion and Fritillaria.
The botanic name Lilium is a Linnaean name. The Latin name is derived from the Greek λείριον, leírion assumed to refer to true, white lilies as exemplified by the Madonna lily; the word was borrowed from Coptic hleri, from standard hreri, from Demotic hrry, from Egyptian hrṛt "flower". Meillet maintains that both the Egyptian and the Greek word are possible loans from an extinct, substratum language of the Eastern Mediterranean; the Greeks used the word κρῖνον, krīnon, albeit for non-white lilies. The term "lily" has in the past been applied to numerous flowering plants with only superficial resemblance to the true lily, including water lily, fire lily, lily of the Nile, calla lily, trout lily, kaffir lily, cobra lily, lily of the valley, ginger lily, Amazon lily, leek lily, Peruvian lily, others. All English translations of the Bible render the Hebrew shūshan, shōshan, shōshannā as "lily", but the "lily among the thorns" of Song of Solomon, for instance, may be the honeysuckle. For a list of other species described as lilies, see Lily.
The range of lilies in the Old World extends across much of Europe, across most of Asia to Japan, south to India, east to Indochina and the Philippines. In the New World they extend from southern Canada through much of the United States, they are adapted to either woodland habitats montane, or sometimes to grassland habitats. A few can survive in marshland and epiphytes are known in tropical southeast Asia. In general they prefer moderately lime-free soils. Lilies are used as food plants by the larvae of some Lepidoptera species including the Dun-bar. Many species are grown in the garden in temperate and sub-tropical regions, they may be grown as potted plants. Numerous ornamental hybrids have been developed, they can be used in herbaceous borders and shrub plantings, as patio plants. Some lilies Lilium longiflorum, form important cut flower crops; these may be forced for particular markets. Lilies are planted as bulbs in the dormant season, they are best planted in a south-facing sloping aspect, in sun or part shade, at a depth 2½ times the height of the bulb.
Most prefer a porous, loamy soil
Plant ecology
Plant ecology is a subdiscipline of ecology which studies the distribution and abundance of plants, the effects of environmental factors upon the abundance of plants, the interactions among and between plants and other organisms. Examples of these are the distribution of temperate deciduous forests in North America, the effects of drought or flooding upon plant survival, competition among desert plants for water, or effects of herds of grazing animals upon the composition of grasslands. A global overview of the Earth's major vegetation types is provided by O. W. Archibold, he recognizes 11 major vegetation types: tropical forests, tropical savannas, arid regions, Mediterranean ecosystems, temperate forest ecosystems, temperate grasslands, coniferous forests, terrestrial wetlands, freshwater ecosystems and coastal/marine systems. This breadth of topics shows the complexity of plant ecology, since it includes plants from floating single-celled algae up to large canopy forming trees. One feature that defines plants is photosynthesis.
Photosynthesis is the process of a chemical reactions to create glucose and oxgyen, vital for plant life. One of the most important aspects of plant ecology is the role plants have played in creating the oxygenated atmosphere of earth, an event that occurred some 2 billion years ago, it can be dated by the deposition of banded iron formations, distinctive sedimentary rocks with large amounts of iron oxide. At the same time, plants began removing carbon dioxide from the atmosphere, thereby initiating the process of controlling Earth's climate. A long term trend of the Earth has been toward increasing oxygen and decreasing carbon dioxide, many other events in the Earth's history, like the first movement of life onto land, are tied to this sequence of events. One of the early classic books on plant ecology was written by J. E. Weaver and F. E. Clements, it talks broadly about plant communities, the importance of forces like competition and processes like succession. Plant ecology can be divided by levels of organization including plant ecophysiology, plant population ecology, community ecology, ecosystem ecology, landscape ecology and biosphere ecology.
The study of plants and vegetation is complicated by their form. First, most plants are rooted in the soil, which makes it difficult to observe and measure nutrient uptake and species interactions. Second, plants reproduce vegetatively, asexually, in a way that makes it difficult to distinguish individual plants. Indeed, the concept of an individual is doubtful, since a tree may be regarded as a large collection of linked meristems. Hence, plant ecology and animal ecology have different styles of approach to problems that involve processes like reproduction and mutualism; some plant ecologists have placed considerable emphasis upon trying to treat plant populations as if they were animal populations, focusing on population ecology. Many other ecologists believe that while it is useful to draw upon population ecology to solve certain scientific problems, plants demand that ecologists work with multiple perspectives, appropriate to the problem, the scale and the situation. Plant ecology has its origin in the application of plant physiology to the questions raised by plant geographers.
Carl Ludwig Willdenow was one of the first to note that similar climates produced similar types of vegetation when they were located in different parts of the world. Willdenow's student, Alexander von Humboldt, used physiognomy to describe vegetation types and observed that the distribution vegetation types was based on environmental factors. Plant geographers who built upon Humboldt's work included Joakim Frederik Schouw, A. P. de Candolle, August Grisebach and Anton Kerner von Marilaun. Schouw's work, published in 1822, linked plant distributions to environmental factors and established the practice of naming plant associations by adding the suffix -etum to the name of the dominant species. Working from herbarium collections, De Candolle searched for general rules of plant distribution and settled on using temperature as well. Grisebach's two-volume work, Die Vegetation der Erde nach Ihrer Klimatischen Anordnung, published in 1872, saw plant geography reach its "ultimate form" as a descriptive field.
Starting in the 1870s, Swiss botanist Simon Schwendener, together with his students and colleagues, established the link between plant morphology and physiological adaptations, laying the groundwork for the first ecology textbooks, Eugenius Warming's Plantesamfund and Andreas Schimper's 1898 Pflanzengeographie auf Physiologischer Grundlage. Warming incorporated plant morphology, physiology taxonomy and biogeography into plant geography to create the field of plant ecology. Although more morphological than physiological, Schimper's has been considered the beginning of plant physiological ecology. Plant ecology was built around static ideas of plant distribution. Henry Chandler Cowles' studies of plant succession on the Lake Michigan sand dunes and Frederic Clements' 1916 monograph on the subject established it as a key element of plant ecology. Plant ecology developed within the wider discipline of ecology over the twentieth century. Inspired by Warming's Plantesamfund, Arthur Tansley set out to map British plant communities.
In 1904 he teamed up with William Gardner Smith and others involved in vegetation mapping to establish the Central Committee for the Survey and Study of British Vegetation shortened to British Vegetation Committee. In 1913, the British Vegetation Committee organised the British Ecological
Perianth
The perianth is the non-reproductive part of the flower, structure that forms an envelope surrounding the sexual organs, consisting of the calyx and the corolla. The term perianth is derived from the Greek περί, meaning around, άνθος, meaning flower, while perigonium is derived from gonos, meaning seed, i.e. sexual organs. In the mosses and liverworts, the perianth is the sterile tubelike tissue that surrounds the female reproductive structure. In flowering plants, the perianth may be described as being either dichlamydeous/heterochlamydeous in which the calyx and corolla are separate, or homochlamydeous, in which they are indistinguishable; when the perianth is in two whorls, it is described as biseriate. While the calyx may be green, known as sepaloid, it may be brightly coloured, is described as petaloid; when the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots.
The corolla and petals have a role in attracting pollinators, but this may be augmented by more specialised structures like the corona. When the corolla consists of separate tepals the term apotepalous is used, or syntepalous if the tepals are fused to one another; the petals may be united to form a tubular corolla. If either the petals or sepals are absent, the perianth can be described as being monochlamydeous. Both sepals and petals may have stomata and veins if vestigial. In some taxa, for instance some magnolias and water lilies the perianth is arranged in a spiral on nodes, rather than whorls. Flowers with spiral perianths tend to be those with undifferentiated perianths. An additional structure in some plants is the corona, a ring or set of appendages of adaxial tissue arising from the corolla or the outer edge of the stamens, it is positioned where the corolla lobes arise from the corolla tube. The pappus of Asteraceae, considered to be a modified calyx, is called a corona if it is shaped like a crown.
Simpson, Michael G.. Plant Systematics. Academic Press. ISBN 0-08-051404-9. Retrieved 12 February 2014; the dictionary definition of perianth at Wiktionary
