122-531: Elizabeth Gertrude Britton (née Knight ) (January 9, 1858 – February 25, 1934) was an American botanist , bryologist , and educator. She and her husband, Nathaniel Lord Britton , played a significant role in the fundraising and creation of the New York Botanical Garden . She was a co-founder of the precursor body to the American Bryological and Lichenological Society . She was an activist for
244-424: A protonema , which is either a mass of thread-like filaments or a flattened thallus. The protonema is a transitory stage in the life of a liverwort, from which will grow the mature gametophore (" gamete -bearer") plant that produces the sex organs. The male organs are known as antheridia ( singular: antheridium) and produce the sperm cells. Clusters of antheridia are enclosed by a protective layer of cells called
366-483: A botanically and pharmacologically important herbal Historia Plantarum in 1544 and a pharmacopoeia of lasting importance, the Dispensatorium in 1546. Naturalist Conrad von Gesner (1516–1565) and herbalist John Gerard (1545– c. 1611 ) published herbals covering the supposed medicinal uses of plants. Naturalist Ulisse Aldrovandi (1522–1605) was considered the father of natural history , which included
488-414: A considerable problem in agriculture, and the biology and control of plant pathogens in agriculture and natural ecosystems . Ethnobotany is the study of the relationships between plants and people. When applied to the investigation of historical plant–people relationships ethnobotany may be referred to as archaeobotany or palaeoethnobotany . Some of the earliest plant-people relationships arose between
610-452: A continuum between the major morphological categories of root, stem (caulome), leaf (phyllome) and trichome . Furthermore, it emphasises structural dynamics. Modern systematics aims to reflect and discover phylogenetic relationships between plants. Modern Molecular phylogenetics largely ignores morphological characters, relying on DNA sequences as data. Molecular analysis of DNA sequences from most families of flowering plants enabled
732-447: A division of non-vascular land plants commonly referred to as hepatics or liverworts . Like mosses and hornworts , they have a gametophyte -dominant life cycle, in which cells of the plant carry only a single set of genetic information. The division name was derived from the genus name Marchantia , named by French botanist Jean Marchant after his father. It is estimated that there are about 9000 species of liverworts. Some of
854-400: A hierarchical classification of plant species that remains the reference point for modern botanical nomenclature . This established a standardised binomial or two-part naming scheme where the first name represented the genus and the second identified the species within the genus. For the purposes of identification, Linnaeus's Systema Sexuale classified plants into 24 groups according to
976-526: A monophyletic clade ("Bryophyta sensu lato " or "Bryophyta Schimp.") alongside mosses and hornworts. Hence, it has been suggested that the liverworts should be de-ranked to a class called Marchantiopsida. In addition, there is strong phylogenetic evidence to suggest that liverworts and mosses form a monophyletic subclade named Setaphyta . vascular plants hornworts mosses liverworts vascular plants hornworts mosses liverworts An important conclusion from these phylogenies
1098-525: A nuisance in shady greenhouses or a weed in gardens. Most liverworts are small, measuring from 2–20 millimetres (0.08–0.8 in) wide with individual plants less than 10 centimetres (4 in) long, so they are often overlooked. The most familiar liverworts consist of a prostrate, flattened, ribbon-like or branching structure called a thallus (plant body); these liverworts are termed thallose liverworts . However, most liverworts produce flattened stems with overlapping scales or leaves in two or more ranks,
1220-404: A plant sucks water through them under water stress. Lignin is also used in other cell types like sclerenchyma fibres that provide structural support for a plant and is a major constituent of wood. Sporopollenin is a chemically resistant polymer found in the outer cell walls of spores and pollen of land plants responsible for the survival of early land plant spores and the pollen of seed plants in
1342-552: A polymer of fructose is used for the same purpose in the sunflower family Asteraceae . Some of the glucose is converted to sucrose (common table sugar) for export to the rest of the plant. Unlike in animals (which lack chloroplasts), plants and their eukaryote relatives have delegated many biochemical roles to their chloroplasts , including synthesising all their fatty acids , and most amino acids . The fatty acids that chloroplasts make are used for many things, such as providing material to build cell membranes out of and making
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#17330927869451464-460: A process that generates molecular oxygen (O 2 ) as a by-product. The light energy captured by chlorophyll a is initially in the form of electrons (and later a proton gradient ) that's used to make molecules of ATP and NADPH which temporarily store and transport energy. Their energy is used in the light-independent reactions of the Calvin cycle by the enzyme rubisco to produce molecules of
1586-505: A pure form of carbon made by pyrolysis of wood, has a long history as a metal- smelting fuel, as a filter material and adsorbent and as an artist's material and is one of the three ingredients of gunpowder . Cellulose , the world's most abundant organic polymer, can be converted into energy, fuels, materials and chemical feedstock. Products made from cellulose include rayon and cellophane , wallpaper paste , biobutanol and gun cotton . Sugarcane , rapeseed and soy are some of
1708-526: A student of Aristotle who invented and described many of its principles and is widely 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 , almost seventeen centuries later. Another work from Ancient Greece that made an early impact on botany
1830-400: A typical liverwort plant each contain only a single set of genetic information, so the plant's cells are haploid for the majority of its life cycle. This contrasts sharply with the pattern exhibited by nearly all animals and by vascular plants. In the more familiar seed plants , the haploid generation is represented only by the tiny pollen and the ovule , while the diploid generation is
1952-454: A useful proxy for temperature in historical climatology , and the biological impact of climate change and global warming . Palynology , the analysis of fossil pollen deposits in sediments from thousands or millions of years ago allows the reconstruction of past climates. Estimates of atmospheric CO 2 concentrations since the Palaeozoic have been obtained from stomatal densities and
2074-1010: A variety of spatial scales in groups, populations and communities that collectively constitute vegetation. Regions with characteristic vegetation types and dominant plants as well as similar abiotic and biotic factors, climate , and geography make up biomes like tundra or tropical rainforest . Herbivores eat plants, but plants can defend themselves and some species are parasitic or even carnivorous . Other organisms form mutually beneficial relationships with plants. For example, mycorrhizal fungi and rhizobia provide plants with nutrients in exchange for food, ants are recruited by ant plants to provide protection, honey bees , bats and other animals pollinate flowers and humans and other animals act as dispersal vectors to spread spores and seeds . Plant responses to climate and other environmental changes can inform our understanding of how these changes affect ecosystem function and productivity. For example, plant phenology can be
2196-628: A way of drug discovery . Plants can synthesise coloured dyes and pigments such as the anthocyanins responsible for the red colour of red wine , yellow weld and blue woad used together to produce Lincoln green , indoxyl , source of the blue dye indigo traditionally used to dye denim and the artist's pigments gamboge and rose madder . Sugar, starch , cotton, linen , hemp , some types of rope , wood and particle boards , papyrus and paper, vegetable oils , wax , and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal ,
2318-452: A wider range of shared characters and were widely followed. The Candollean system reflected his ideas of the progression of morphological complexity and the later Bentham & Hooker system , which was influential until the mid-19th century, was influenced by Candolle's approach. Darwin 's publication of the Origin of Species in 1859 and his concept of common descent required modifications to
2440-406: Is De materia medica , a five-volume encyclopedia about preliminary herbal medicine written in the middle of the first century by Greek physician and pharmacologist Pedanius Dioscorides . De materia medica was widely read for more than 1,500 years. Important contributions from the medieval Muslim world include Ibn Wahshiyya 's Nabatean Agriculture , Abū Ḥanīfa Dīnawarī 's (828–896)
2562-405: Is peppermint , Mentha × piperita , a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata . The many cultivated varieties of wheat are the result of multiple inter- and intra- specific crosses between wild species and their hybrids. Angiosperms with monoecious flowers often have self-incompatibility mechanisms that operate between the pollen and stigma so that
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#17330927869452684-474: Is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word botanē ( βοτάνη ) meaning " pasture ", " herbs " " grass ", or " fodder "; Botanē is in turn derived from boskein ( Greek : βόσκειν ), "to feed" or "to graze ". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with
2806-476: Is a broad, multidisciplinary subject with contributions and insights from most other areas of science and technology. Research topics include the study of plant structure , growth and differentiation, reproduction , biochemistry and primary metabolism , chemical products, development , diseases , evolutionary relationships , systematics , and plant taxonomy . Dominant themes in 21st-century plant science are molecular genetics and epigenetics , which study
2928-762: Is gathered by ethnobotanists. This information can relay a great deal of information on how the land once was thousands of years ago and how it has changed over that time. The goals of plant ecology are to understand the causes of their distribution patterns, productivity, environmental impact, evolution, and responses to environmental change. Plants depend on certain edaphic (soil) and climatic factors in their environment but can modify these factors too. For example, they can change their environment's albedo , increase runoff interception, stabilise mineral soils and develop their organic content, and affect local temperature. Plants compete with other organisms in their ecosystem for resources. They interact with their neighbours at
3050-669: Is now known as the Native Plant Garden, and the boulder as Britton Rock. Today, the Elizabeth Gertrude Knight Britton archive is held by the NYBG Mertz Library . It includes personal papers, manuscripts and published research, artwork and photographs, and printing plates. The archive documents Britton's teaching career at Normal College, as well as her participation in the Torrey Botanical Club and
3172-451: Is still a major foundation of modern botany. Her books Plant Anatomy and Anatomy of Seed Plants have been key plant structural biology texts for more than half a century. The discipline of plant ecology was pioneered in the late 19th century by botanists such as Eugenius Warming , who produced the hypothesis that plants form communities , and his mentor and successor Christen C. Raunkiær whose system for describing plant life forms
3294-400: Is still given to these groups by botanists, and fungi (including lichens) and photosynthetic protists are usually covered in introductory botany courses. Palaeobotanists study ancient plants in the fossil record to provide information about the evolutionary history of plants . Cyanobacteria , the first oxygen-releasing photosynthetic organisms on Earth, are thought to have given rise to
3416-444: Is still in use today. The concept that the composition of plant communities such as temperate broadleaf forest changes by a process of ecological succession was developed by Henry Chandler Cowles , Arthur Tansley and Frederic Clements . Clements is credited with the idea of climax vegetation as the most complex vegetation that an environment can support and Tansley introduced the concept of ecosystems to biology. Building on
3538-623: Is still uncertain, so it may not belong to the Marchantiophyta. In 2007, the oldest fossils assignable at that time to the liverworts were announced, Metzgeriothallus sharonae from the Givetian (Middle Devonian ) of New York , United States. However, in 2010, five different types of fossilized liverwort spores were found in Argentina, dating to the much earlier Middle Ordovician , around 470 million years ago. Bryologists classify liverworts in
3660-516: Is that the ancestral stomata appear to have been lost in the liverwort lineage. Among the earliest fossils believed to be liverworts are compression fossils of Pallaviciniites from the Upper Devonian of New York . These fossils resemble modern species in the Metzgeriales . Another Devonian fossil called Protosalvinia also looks like a liverwort, but its relationship to other plants
3782-498: Is the study of ferns and allied plants. A number of other taxa of ranks varying from family to subgenus have terms for their study, including agrostology (or graminology) for the study of grasses, synantherology for the study of composites, and batology for the study of brambles. Study can also be divided by guild rather than clade or grade . Dendrology is the study of woody plants. Many divisions of biology have botanical subfields. These are commonly denoted by prefixing
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3904-553: The Angiosperm Phylogeny Group to publish in 1998 a phylogeny of flowering plants, answering many of the questions about relationships among angiosperm families and species. The theoretical possibility of a practical method for identification of plant species and commercial varieties by DNA barcoding is the subject of active current research. Botany is divided along several axes. Some subfields of botany relate to particular groups of organisms. Divisions related to
4026-495: The Book of Plants , and Ibn Bassal 's The Classification of Soils . In the early 13th century, Abu al-Abbas al-Nabati , and Ibn al-Baitar (d. 1248) 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 usually considered to be the first which is still in its original location. These gardens continued
4148-417: The C 4 carbon fixation pathway for photosynthesis which avoid the losses resulting from photorespiration in the more common C 3 carbon fixation pathway. These biochemical strategies are unique to land plants. Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism . Some of these compounds are toxins such as
4270-514: The Late Silurian / Early Devonian . When the sporophyte has developed all three regions, the seta elongates, pushing its way out of the archegonium and rupturing it. While the foot remains anchored within the parent plant, the capsule is forced out by the seta and is extended away from the plant and into the air. Within the capsule, cells divide to produce both elater cells and spore-producing cells. The elaters are spring-like, and will push open
4392-504: The alkaloid coniine from hemlock . Others, such as the essential oils peppermint oil and lemon oil are useful for their aroma, as flavourings and spices (e.g., capsaicin ), and in medicine as pharmaceuticals as in opium from opium poppies . Many medicinal and recreational drugs , such as tetrahydrocannabinol (active ingredient in cannabis ), caffeine , morphine and nicotine come directly from plants. Others are simple derivatives of botanical natural products. For example,
4514-565: The auxin plant hormones by Kenneth V. Thimann in 1948 enabled regulation of plant growth by externally applied chemicals. Frederick Campion Steward pioneered techniques of micropropagation and plant tissue culture controlled by plant hormones . The synthetic auxin 2,4-dichlorophenoxyacetic acid or 2,4-D was one of the first commercial synthetic herbicides . 20th century developments in plant biochemistry have been driven by modern techniques of organic chemical analysis , such as spectroscopy , chromatography and electrophoresis . With
4636-626: The cell theory with Theodor Schwann and Rudolf Virchow and was among the first to grasp the significance of the cell nucleus that had been described by Robert Brown in 1831. In 1855, Adolf Fick formulated Fick's laws that enabled the calculation of the rates of molecular diffusion in biological systems. Building upon the gene-chromosome theory of heredity that originated with Gregor Mendel (1822–1884), August Weismann (1834–1914) proved that inheritance only takes place through gametes . No other cells can pass on inherited characters. The work of Katherine Esau (1898–1997) on plant anatomy
4758-444: The cellulose and lignin used to build their bodies, and secondary products like resins and aroma compounds . Plants and various other groups of photosynthetic eukaryotes collectively known as " algae " have unique organelles known as chloroplasts . Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain
4880-427: The indigenous people of Canada in identifying edible plants from inedible plants. This relationship the indigenous people had with plants was recorded by ethnobotanists. Plant biochemistry is the study of the chemical processes used by plants. Some of these processes are used in their primary metabolism like the photosynthetic Calvin cycle and crassulacean acid metabolism . Others make specialised materials like
5002-515: The perigonium ( plural: perigonia). As in other land plants, the female organs are known as archegonia ( singular: archegonium) and are protected by the thin surrounding perichaetum ( plural: perichaeta). Each archegonium has a slender hollow tube, the "neck", down which the sperm swim to reach the egg cell. Liverwort species may be either dioicous or monoicous . In dioicous liverworts, female and male sex organs are borne on different and separate gametophyte plants. In monoicous liverworts,
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5124-426: The pines , and flowering plants ) and the free-sporing cryptogams including ferns , clubmosses , liverworts , hornworts and mosses . Embryophytes are multicellular eukaryotes descended from an ancestor that obtained its energy from sunlight by photosynthesis . They have life cycles with alternating haploid and diploid phases. The sexual haploid phase of embryophytes, known as the gametophyte , nurtures
5246-408: The 3-carbon sugar glyceraldehyde 3-phosphate (G3P). Glyceraldehyde 3-phosphate is the first product of photosynthesis and the raw material from which glucose and almost all other organic molecules of biological origin are synthesised. Some of the glucose is converted to starch which is stored in the chloroplast. Starch is the characteristic energy store of most land plants and algae, while inulin ,
5368-592: The Brittons. In 1940, a memorial plaque in honor of Britton was installed in the new Wild Flower Garden of the New York Botanical Garden. A gift of the New York Bird and Tree Club, it is mounted on a ten-ton boulder of Bronx schist, and its text reads, "Let those who find pleasure in this garden remember Elizabeth Gertrude Knight Britton, lover of wildflowers and ardent advocate of their protection". The garden
5490-506: The Candollean system to reflect evolutionary relationships as distinct from mere morphological similarity. Botany was greatly stimulated by the appearance of the first "modern" textbook, Matthias Schleiden 's Grundzüge der Wissenschaftlichen Botanik , published in English in 1849 as Principles of Scientific Botany . Schleiden was a microscopist and an early plant anatomist who co-founded
5612-582: The Mosses for a popular magazine was published in 1894. These papers "sufficed to place Mrs. Britton in command of the bryological field in America." She worked with her husband to acquire for Columbia the moss herbarium of August Jaeger of Switzerland; Britton persuaded wealthy friends to contribute the necessary $ 6,000. Britton, along with her husband, was one of the Torrey Botanical Club members who spurred
5734-709: The NYBG spurred the creation of the Wild Flower Preservation Society of America . The first meeting was held on April 23, 1902, where Frederick Vernon Coville was elected president, Charles Louis Pollard was elected secretary, and Britton was elected to the Board of Managers. Other members of the board included Charles Edwin Bessey , Liberty Hyde Bailey , William Trelease , Charles Frederick Millspaugh and Alice Eastwood . Britton went on to serve as secretary and treasurer of
5856-534: The NYBG's Journal under the series title of Wild Plants Needing Protection . The series of articles gives evidence of Britton writing in an accessible, non-technical register, such as the introduction of "Wild Pink" ( Silene caroliniana ): Before the trees cast much shade, while their greens are still so exquisitely fresh and varied, a bright flash of color will attract the eye to the Wild Pink, growing in hilly places on rocks or often in their cracks and crevices with
5978-578: The NYBG. Her field notebooks can be found in the New York Botanical Garden Collectors' Field Notebook collection. The character of Alma Whittaker in the 2013 novel The Signature of All Things , by Elizabeth Gilbert , is modeled in part on Britton. Elizabeth Britton died at her home at 2965 Decatur Avenue in The Bronx on February 25, 1934, following an apoplectic stroke ; her husband Nathaniel survived her for four months. Although she
6100-478: The New York Botanical Garden's Flora of America . Marshall Avery Howe described Britton as "a woman of extraordinary physical and mental energy—the possessor of a remarkably quick and brilliant intellect. She has left an enduring record in the literature of science, and her well-directed activities have had an outstanding influence in the conservation of the native flora of the United States." In 1893, Britton
6222-552: The North American Species of Ophioglossum, the adder's-tongue ferns , in 1897. With Delia West Marble, she collected the type specimen of Thelypteris brittonae , a species of maiden fern , in 1906. Britton collected the type specimen for the orchid now named Britton's shadow witch ( Ponthieva brittoniae ). In the first decade of the 20th century, Britton began to devote her time to the conservation of wildflowers . A gift of $ 3,000 by Olivia and Caroline Phelps Stokes to
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#17330927869456344-628: The Saxifrage. In 1925, as chair of the conservation committee of the Federated Garden Clubs of New York State, Britton successfully led a boycott campaign against the common practice of harvesting wild American holly for use as a Christmas decoration. As a substitute, she promoted the propagation of the plant by cuttings for commercial use. All told, during the period 1881 to 1930, Britton published 346 papers, of which 170 dealt with mosses. She wrote descriptions of six families of mosses for
6466-714: The United States to collect botanical specimens, including the Great Dismal Swamp , the Adirondack Mountains , and the mountains of North Carolina . She accompanied Nathaniel on 23 of the 25 trips he made to the islands of the Caribbean and West Indies . Under her own name, she published her findings in the Bulletin in 1913–1915. Britton wrote the chapters concerning mosses for Nathaniel's Flora of Bermuda and The Bahama Flora . Britton worked with organizations to promote
6588-474: The Vegetable Kingdom at the start of chapter XII noted "The first and most important of the conclusions which may be drawn from the observations given in this volume, is that generally cross-fertilisation is beneficial and self-fertilisation often injurious, at least with the plants on which I experimented." An important adaptive benefit of outcrossing is that it allows the masking of deleterious mutations in
6710-412: The above pair of categories gives rise to fields such as bryogeography (the study of the distribution of mosses). Different parts of plants also give rise to their own subfields, including xylology , carpology (or fructology) and palynology , these been the study of wood, fruit and pollen/spores respectively. Botany also overlaps on the one hand with agriculture, horticulture and silviculture, and on
6832-439: The ancestor of plants by entering into an endosymbiotic relationship with an early eukaryote, ultimately becoming the chloroplasts in plant cells. The new photosynthetic plants (along with their algal relatives) accelerated the rise in atmospheric oxygen started by the cyanobacteria , changing the ancient oxygen-free, reducing , atmosphere to one in which free oxygen has been abundant for more than 2 billion years. Among
6954-475: The archegonium develops three distinct regions: (1) a foot , which both anchors the sporophyte in place and receives nutrients from its "mother" plant, (2) a spherical or ellipsoidal capsule , inside which the spores will be produced for dispersing to new locations, and (3) a seta (stalk) which lies between the other two regions and connects them. The sporophyte lacks an apical meristem , an auxin -sensitive point of divergence with other land plants some time in
7076-447: The base of most food chains because they use the energy from the sun and nutrients from the soil and atmosphere, converting them into a form that can be used by animals. This is what ecologists call the first trophic level . The modern forms of the major staple foods , such as hemp , teff , maize, rice, wheat and other cereal grasses, pulses , bananas and plantains, as well as hemp , flax and cotton grown for their fibres, are
7198-500: The blue-green pigment chlorophyll a . Chlorophyll a (as well as its plant and green algal-specific cousin chlorophyll b ) absorbs light in the blue-violet and orange/red parts of the spectrum while reflecting and transmitting the green light that we see as the characteristic colour of these organisms. The energy in the red and blue light that these pigments absorb is used by chloroplasts to make energy-rich carbon compounds from carbon dioxide and water by oxygenic photosynthesis ,
7320-446: The broader historical sense of botany include bacteriology , mycology (or fungology) and phycology - the study of bacteria, fungi and algae respectively - with lichenology as a subfield of mycology. The narrower sense of botany in the sense of the study of embryophytes (land plants) is disambiguated as phytology. Bryology is the study of mosses (and in the broader sense also liverworts and hornworts). Pteridology (or filicology)
7442-504: The characters may be artificial in keys designed purely for identification ( diagnostic keys ) or more closely related to the natural or phyletic order of the taxa in synoptic keys. By the 18th century, new plants for study were arriving in Europe in increasing numbers from newly discovered countries and the European colonies worldwide. In 1753, Carl Linnaeus published his Species Plantarum ,
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#17330927869457564-567: The couple set about organizing an institution of comparable stature for New York. A Club meeting was held in October 1888 where rich and prominent citizens were recruited as incorporators. The Botanical Garden was established by act of the state legislature in 1891. Britton was important in the efforts to raise funds for the organization in the 1890s. Her husband became the first director of the Botanical Garden in 1896, whilst she volunteered there. It
7686-550: The cytoplasm of all other plants being unenclosed. The overall physical similarity of some mosses and leafy liverworts means that confirmation of the identification of some groups can be performed with certainty only with the aid of microscopy or an experienced bryologist . Liverworts, like other bryophytes, have a gametophyte -dominant life cycle, with the sporophyte dependent on the gametophyte. The sporophyte of many liverworts are non-photosynthetic, but there are also several that are photosynthetic to various degrees. Cells in
7808-461: The developing diploid embryo sporophyte within its tissues for at least part of its life, even in the seed plants, where the gametophyte itself is nurtured by its parent sporophyte. Other groups of organisms that were previously studied by botanists include bacteria (now studied in bacteriology ), fungi ( mycology ) – including lichen -forming fungi ( lichenology ), non- chlorophyte algae ( phycology ), and viruses ( virology ). However, attention
7930-436: The division Marchantiophyta . This divisional name is based on the name of the most universally recognized liverwort genus Marchantia . In addition to this taxon -based name, the liverworts are often called Hepaticophyta . This name is derived from their common Latin name as Latin was the language in which botanists published their descriptions of species. This name has led to some confusion, partly because it appears to be
8052-459: 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 and led in 1753 to the binomial system of nomenclature of Carl Linnaeus that remains in use to this day for the naming of all biological species. In the 19th and 20th centuries, new techniques were developed for
8174-419: The efforts of early humans to identify – and later cultivate – plants that were edible, poisonous, and possibly medicinal, making it one of the first endeavours of human investigation. Medieval physic gardens , often attached to monasteries , contained plants possibly having medicinal benefit. They were forerunners of the first botanical gardens attached to universities , founded from the 1540s onwards. One of
8296-547: The entire surface of containers; gemma dispersal is the "primary mechanism by which liverwort spreads throughout a nursery or greenhouse." Thalloid liverworts typically harbor symbiotic glomeromycete fungi which have arbuscular (cilia-bearing) rootlets resembling those in vascular plants. Species in the Aneuraceae , however, associate with basidiomycete fungi belonging to the genus Tulasnella , while leafy liverworts typically harbor symbiotic basidiomycete fungi belonging to
8418-615: The establishment of the New York Botanical Garden (NYBG). The couple also travelled to England in 1888 where Nathaniel was performing research at the Royal Botanic Gardens, Kew . At Kew Nathaniel worked on the Bolivian botanical collections of Henry Hurd Rusby , a gift to Columbia; meanwhile, Elizabeth worked on mosses at the Linnean Society of London . Inspired by the quality and quantity of Kew's herbarium , library, and gardens,
8540-453: The extensive earlier work of Alphonse de Candolle , Nikolai Vavilov (1887–1943) produced accounts of the biogeography , centres of origin , and evolutionary history of economic plants. Particularly since the mid-1960s there have been advances in understanding of the physics of plant physiological processes such as transpiration (the transport of water within plant tissues), the temperature dependence of rates of water evaporation from
8662-411: The familiar tree or other plant. Another unusual feature of the liverwort life cycle is that sporophytes (i.e. the diploid body) are very short-lived, withering away not long after releasing spores. In mosses, the sporophyte is more persistent and in hornworts, the sporophyte disperses spores over an extended period. The life of a liverwort starts from the germination of a haploid spore to produce
8784-563: The fossil record. It is widely regarded as a marker for the start of land plant evolution during the Ordovician period. The concentration of carbon dioxide in the atmosphere today is much lower than it was when plants emerged onto land during the Ordovician and Silurian periods. Many monocots like maize and the pineapple and some dicots like the Asteraceae have since independently evolved pathways like Crassulacean acid metabolism and
8906-451: The functional relationships between plants and their habitats – the environments where they complete their life cycles . Plant ecologists study the composition of local and regional floras , their biodiversity , genetic diversity and fitness , the adaptation of plants to their environment, and their competitive or mutualistic interactions with other species. Some ecologists even rely on empirical data from indigenous people that
9028-458: The genome of progeny. This beneficial effect is also known as hybrid vigor or heterosis. Once outcrossing is established, subsequent switching to inbreeding becomes disadvantageous since it allows expression of the previously masked deleterious recessive mutations, commonly referred to as inbreeding depression. Marchantiophyta The Marchantiophyta ( / m ɑːr ˌ k æ n t i ˈ ɒ f ə t ə , - oʊ ˈ f aɪ t ə / ) are
9150-485: The genus Serendipita . Today, liverworts can be found in many ecosystems across the planet except the sea and excessively dry environments, or those exposed to high levels of direct solar radiation. As with most groups of living plants, they are most common (both in numbers and species) in moist tropical areas. Liverworts are more commonly found in moderate to deep shade, though desert species may tolerate direct sunlight and periods of total desiccation. Traditionally,
9272-444: The global carbon and water cycles and plant roots bind and stabilise soils, preventing soil erosion . Plants are crucial to the future of human society as they provide food, oxygen, biochemicals , and products for people, as well as creating and preserving soil. Historically, all living things were classified as either animals or plants and botany covered the study of all organisms not considered animals. Botanists examine both
9394-621: The important botanical questions of the 21st century are the role of plants as primary producers in the global cycling of life's basic ingredients: energy, carbon, oxygen, nitrogen and water, and ways that our plant stewardship can help address the global environmental issues of resource management , conservation , human food security , biologically invasive organisms , carbon sequestration , climate change , and sustainability . Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them. Plants and other photosynthetic organisms are at
9516-478: The internal functions and processes within plant organelles , cells, tissues, whole plants, plant populations and plant communities. At each of these levels, a botanist may be concerned with the classification ( taxonomy ), phylogeny and evolution , structure ( anatomy and morphology ), or function ( physiology ) of plant life. The strictest definition of "plant" includes only the "land plants" or embryophytes , which include seed plants (gymnosperms, including
9638-403: The leaf shapes and sizes of ancient land plants . Ozone depletion can expose plants to higher levels of ultraviolet radiation-B (UV-B), resulting in lower growth rates. Moreover, information from studies of community ecology , plant systematics , and taxonomy is essential to understanding vegetation change , habitat destruction and species extinction . Inheritance in plants follows
9760-576: The leaf surface and the molecular diffusion of water vapour and carbon dioxide through stomatal apertures. These developments, coupled with new methods for measuring the size of stomatal apertures, and the rate of photosynthesis have enabled precise description of the rates of gas exchange between plants and the atmosphere. Innovations in statistical analysis by Ronald Fisher , Frank Yates and others at Rothamsted Experimental Station facilitated rational experimental design and data analysis in botanical research. The discovery and identification of
9882-509: The liverworts were grouped together with other bryophytes ( mosses and hornworts ) in the Division Bryophyta, within which the liverworts made up the class Hepaticae (also called Marchantiopsida). Somewhat more recently, the liverworts were given their own division (Marchantiophyta), as bryophytes became considered to be paraphyletic . However, the most recent phylogenetic evidence indicates that liverworts are indeed likely part of
10004-576: The maintenance of biodiversity . Botany originated as herbalism , the study and use of plants for their possible medicinal properties . 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 BCE, Ancient Egypt , in archaic Avestan writings, and in works from China purportedly from before 221 BCE. Modern botany traces its roots back to Ancient Greece specifically to Theophrastus ( c. 371 –287 BCE),
10126-493: The major groups of organisms that carry out photosynthesis , a process that uses the energy of sunlight to convert water and carbon dioxide into sugars that can be used both as a source of chemical energy and of organic molecules that are used in the structural components of cells. As a by-product of photosynthesis, plants release oxygen into the atmosphere, a gas that is required by nearly all living things to carry out cellular respiration. In addition, they are influential in
10248-474: 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 , oil , rubber, fibre and drugs, in modern horticulture , agriculture and forestry , plant propagation , breeding and genetic modification , in the synthesis of chemicals and raw materials for construction and energy production, in environmental management , and
10370-465: The middle rank is often conspicuously different from the outer ranks; these are called leafy liverworts or scale liverworts . ( See the gallery below for examples. ) Liverworts can most reliably be distinguished from the apparently similar mosses by their single-celled rhizoids . Other differences are not universal for all mosses and all liverworts; but the lack of clearly differentiated stem and leaves in thallose species, or in leafy species
10492-540: The more familiar species grow as a flattened leafless thallus , but most species are leafy with a form very much like a flattened moss . Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, including their single-celled rhizoids . Leafy liverworts also differ from most (but not all) mosses in that their leaves never have a costa (present in many mosses) and may bear marginal cilia (very rare in mosses). Other differences are not universal for all mosses and liverworts, but
10614-401: The moss collections at Columbia in an unofficial, unpaid capacity. She served as editor of the Bulletin of the Torrey Botanical Club from 1886 to 1888; in 1889, she published the first of an eleven-part series of papers titled Contributions to American Bryology in that journal. Her catalogue of the mosses of West Virginia appeared in 1892, and the first of eight articles titled How to Study
10736-596: The number of their male sexual organs. The 24th group, Cryptogamia , included all plants with concealed reproductive parts, mosses , liverworts , ferns , algae and fungi . Botany was originally a hobby for upper-class women. These women would collect and paint flowers and plants from around the world with scientific accuracy. The paintings were used to record many species that could not be transported or maintained in other environments. Marianne North illustrated over 900 species in extreme detail with watercolor and oil paintings. Her work and many other women's botany work
10858-785: The occurrence of leaves arranged in three ranks, the presence of deep lobes or segmented leaves, or a lack of clearly differentiated stem and leaves all point to the plant being a liverwort. Liverworts are distinguished from mosses in having unique complex oil bodies of high refractive index. Liverworts are typically small, usually from 2–20 mm (0.079–0.787 in) wide with individual plants less than 10 cm (3.9 in) long, and are therefore often overlooked. However, certain species may cover large patches of ground, rocks, trees or any other reasonably firm substrate on which they occur. They are distributed globally in almost every available habitat, most often in humid locations although there are desert and Arctic species as well. Some species can be
10980-441: The older parts of the forked thalli die, the younger tips become separate individuals. Some thallose liverworts such as Marchantia polymorpha and Lunularia cruciata produce small disc-shaped gemmae in shallow cups. Marchantia gemmae can be dispersed up to 120 cm by rain splashing into the cups. In Metzgeria , gemmae grow at thallus margins. Marchantia polymorpha is a common weed in greenhouses, often covering
11102-410: The organization. The Society established numerous local chapters, with a membership largely of women. It was incorporated in the state of New York in 1915. Soon, tensions between field botanists (many of them women) and those with academic affiliations (many of them men), as well as disagreements over centralizing leadership on policy questions (specifically, addressing the growing number of automobiles on
11224-447: The other hand with medicine and pharmacology, giving rise to fields such as agronomy , horticultural botany, phytopathology and phytopharmacology . The study of plants is vital because they underpin almost all animal life on Earth by generating a large proportion of the oxygen and food that provide humans and other organisms with aerobic respiration with the chemical energy they need to exist. Plants, algae and cyanobacteria are
11346-404: The outcome of prehistoric selection over thousands of years from among wild ancestral plants with the most desirable characteristics. Botanists study how plants produce food and how to increase yields, for example through plant breeding , making their work important to humanity's ability to feed the world and provide food security for future generations. Botanists also study weeds, which are
11468-791: The pain killer aspirin is the acetyl ester of salicylic acid , originally isolated from the bark of willow trees, and a wide range of opiate painkillers like heroin are obtained by chemical modification of morphine obtained from the opium poppy . Popular stimulants come from plants, such as caffeine from coffee, tea and chocolate, and nicotine from tobacco. Most alcoholic beverages come from fermentation of carbohydrate -rich plant products such as barley (beer), rice ( sake ) and grapes (wine). Native Americans have used various plants as ways of treating illness or disease for thousands of years. This knowledge Native Americans have on plants has been recorded by enthnobotanists and then in turn has been used by pharmaceutical companies as
11590-479: The plants with a highly fermentable sugar or oil content that are used as sources of biofuels , important alternatives to fossil fuels , such as biodiesel . Sweetgrass was used by Native Americans to ward off bugs like mosquitoes . These bug repelling properties of sweetgrass were later found by the American Chemical Society in the molecules phytol and coumarin . Plant ecology is the science of
11712-486: The pollen either fails to reach the stigma or fails to germinate and produce male gametes . This is one of several methods used by plants to promote outcrossing . In many land plants the male and female gametes are produced by separate individuals. These species are said to be dioecious when referring to vascular plant sporophytes and dioicous when referring to bryophyte gametophytes . Charles Darwin in his 1878 book The Effects of Cross and Self-Fertilization in
11834-442: The polymer cutin which is found in the plant cuticle that protects land plants from drying out. Plants synthesise a number of unique polymers like the polysaccharide molecules cellulose , pectin and xyloglucan from which the land plant cell wall is constructed. Vascular land plants make lignin , a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when
11956-545: The practical value of earlier "physic gardens", often associated with monasteries, in which plants were cultivated for suspected medicinal uses. They supported the growth of botany as an academic subject. Lectures were given about the plants grown in the gardens. Botanical gardens came much later to northern Europe; the first in England was the University of Oxford Botanic Garden in 1621. German physician Leonhart Fuchs (1501–1566)
12078-491: The presence of deeply lobed or segmented leaves and the presence of leaves arranged in three ranks, as well as frequent dichotomous branching, all point to the plant being a liverwort. With a few exceptions, all liverworts undergo polyplastidic meiosis, in contrast to mosses and hornworts which have monoplastidic meiosis. Unlike any other embryophytes, most liverworts contain unique membrane-bound oil bodies containing isoprenoids in at least some of their cells, lipid droplets in
12200-472: The protection of wildflowers, inspiring local chapter activities and the passage of legislation. Elizabeth Britton made major contributions to the literature of mosses, publishing 170 papers in that field. Elizabeth Gertrude Knight was born on January 9, 1858, in New York City , one of five daughters, to James and Sophie Anne (née Compton) Knight. Her family operated a furniture factory and sugar plantation in
12322-461: The rise of the related molecular-scale biological approaches of molecular biology , genomics , proteomics and metabolomics , the relationship between the plant genome and most aspects of the biochemistry, physiology, morphology and behaviour of plants can be subjected to detailed experimental analysis. The concept originally stated by Gottlieb Haberlandt in 1902 that all plant cells are totipotent and can be grown in vitro ultimately enabled
12444-433: The road) led to its reorganization as the Wild Flower Preservation Society in 1925, with Percy L. Ricker as its head. Nevertheless, Britton continued to promote the cause for nearly 35 years, by publishing, lecturing, and conducting correspondence; her efforts led to adoption of legislation in various states, as well as local conservation activities in garden clubs and public schools. She published fourteen short articles in
12566-676: The same fundamental principles of genetics as in other multicellular organisms. Gregor Mendel discovered the genetic laws of inheritance by studying inherited traits such as shape in Pisum sativum ( peas ). What Mendel learned from studying plants has had far-reaching benefits outside of botany. Similarly, " jumping genes " were discovered by Barbara McClintock while she was studying maize. Nevertheless, there are some distinctive genetic differences between plants and other organisms. Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example
12688-413: The splashing of raindrops. In 2008, Japanese researchers discovered that some liverworts are able to fire sperm-containing water up to 15 cm in the air, enabling them to fertilize female plants growing more than a metre from the nearest male. When sperm reach the archegonia, fertilisation occurs, leading to the production of a diploid sporophyte. After fertilisation, the immature sporophyte within
12810-460: The staff of Normal College as a critic teacher. She joined the Torrey Botanical Club in 1879, and in 1881 she published her first scientific paper in that organization's Bulletin , reporting observations of unexpected white flowers in two species of plants. She also observed the presence of a curlygrass fern, Schizaea pusilla , in Nova Scotia . In 1883, she became a tutor in natural science. It
12932-594: The study of mosses, especially by women scientists, and she chaired the division of Bryophyta for the (Women's) National Science Club (NWSC) in 1897. As part of her unofficial position at Columbia, Britton acted as advisor to doctoral students, including James Franklin Collins and Abel Joel Grout . Together, in 1898 Grout and Britton founded the Sullivant Moss Chapter of the Agassiz Association . By 1908, it
13054-450: 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
13176-471: The study of plants. In 1665, using an early microscope, Polymath Robert Hooke discovered cells (a term he coined) in cork , and a short time later in living plant tissue. During the 18th century, systems of plant identification were developed comparable to dichotomous keys , where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters . The choice and sequence of
13298-502: The study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress . Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants , including some 391,000 species of vascular plants (of which approximately 369,000 are flowering plants ) and approximately 20,000 bryophytes . Botany originated in prehistory as herbalism with
13420-435: The two kinds of reproductive structures are borne on different branches of the same plant. In either case, the sperm must move from the antheridia where they are produced to the archegonium where the eggs are held. The sperm of liverworts is biflagellate , i.e. they have two tail-like flagellae that enable them to swim short distances, provided that at least a thin film of water is present. Their journey may be assisted by
13542-526: The use of genetic engineering experimentally to knock out a gene or genes responsible for a specific trait, or to add genes such as GFP that report when a gene of interest is being expressed. These technologies enable the biotechnological use of whole plants or plant cell cultures grown in bioreactors to synthesise pesticides , antibiotics or other pharmaceuticals , as well as the practical application of genetically modified crops designed for traits such as improved yield. Modern morphology recognises
13664-549: The vicinity of Matanzas, Cuba , and she spent much of her childhood there. In later childhood, she attended a private school in New York before attending Normal College (later, Hunter College). She graduated from Normal College in 1875, at the early age of seventeen. On August 27, 1885, she married Nathaniel Lord Britton , an assistant in geology at Columbia College who shared her growing interest in botany. The couple had no children. After graduation in 1875, Elizabeth Knight joined
13786-467: The wall of the capsule to scatter themselves when the capsule bursts. The spore-producing cells will undergo meiosis to form haploid spores to disperse, upon which point the life cycle can start again. Some liverworts are capable of asexual reproduction ; in bryophytes in general "it would almost be true to say that vegetative reproduction is the rule and not the exception." For example, in Riccia , when
13908-485: The word plant (e.g. plant taxonomy, plant ecology, plant anatomy, plant morphology, plant systematics, plant ecology), or prefixing or substituting the prefix phyto- (e.g. phytochemistry , phytogeography ). The study of fossil plants is palaeobotany . Other fields are denoted by adding or substituting the word botany (e.g. systematic botany ). Phytosociology is a subfield of plant ecology that classifies and studies communities of plants. The intersection of fields from
14030-631: Was at this time that she began to specialize in bryology and her first paper concerning mosses appeared. Britton collected fertile specimens of Eustichium norvegicum in Wisconsin and wrote the first description of its fruits. Although known since 1827, the plant had hitherto been known only in a sterile condition. Her Observer articles were models of popular scientific writings on plants which had "fanciful" titles like "The Humpbacked Elves" and "The Brownies". After her marriage in 1885, Britton resigned her teaching position at Normal College, and took charge of
14152-597: Was known as the Sullivant Moss Society (and after 1949, as the American Bryological and Lichenological Society). Although relations between the two researchers later became chilly, Britton continued to participate in the Society, contributing articles to The Bryologist , its journal, and serving as its president from 1916 to 1919. Britton continued to study plants other than mosses. She published A Revision of
14274-479: Was largely through her interest that the collection of liverworts and mosses of William Mitten was acquired for the NYBG in 1906. In recognition of her service, Britton was named Honorary Curator of the Mosses in 1912, a post which she held until her death. Britton enumerated the ferns in the Rusby collection in 1888 and she published her examination of the Rusby mosses in 1896. Britton traveled to various locations in
14396-560: Was marked with an asterisk: this "starred" listing was limited to the top 1,000 scientists in the book, as determined by the editors. Britton was starred in the five editions of the book that appeared through 1933. The moss genus Bryobrittonia is named for Elizabeth Britton, as well as fifteen species of plants and one of animals. Mount Britton , a double peak in El Yunque National Forest in Puerto Rico , honors both of
14518-523: Was nominally a member of the Episcopalian faith, she was buried in the Moravian Cemetery on Staten Island , where her husband's ancestors had been early settlers and he held property. Botanist Botany , also called plant science (or plant sciences ), plant biology or phytology , is the science of plant life and a branch of biology . A botanist , plant scientist or phytologist
14640-399: Was one of "the three German fathers of botany", along with theologian Otto Brunfels (1489–1534) and physician Hieronymus Bock (1498–1554) (also called Hieronymus Tragus). 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 (1515–1544) authored
14762-412: Was the beginning of popularizing botany to a wider audience. Increasing knowledge of plant anatomy , morphology and life cycles led to the realisation that there were more natural affinities between plants than the artificial sexual system of Linnaeus. Adanson (1763), de Jussieu (1789), and Candolle (1819) all proposed various alternative natural systems of classification that grouped plants using
14884-518: Was the only woman among the 25 scientists nominated for charter membership in the Botanical Society of America . In 1905, she was one of three bryologists appointed to the nomenclature committee that would report to the 1910 meeting of the International Botanical Congress in Brussels . In 1906, Britton was one of only nineteen women listed in the first edition of American Men of Science . Her entry
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