Ethnobotany is the study of a region's plants and their practical uses through the traditional knowledge of a local culture and people. An ethnobotanist thus strives to document the local customs involving the practical uses of local flora for many aspects of life, such as plants as medicines and clothing. Richard Evans Schultes referred to as the "father of ethnobotany", explained the discipline in this way: Ethnobotany means... investigating plants used by societies in various parts of the world. Since the time of Schultes, the field of ethnobotany has grown from acquiring ethnobotanical knowledge to that of applying it to a modern society in the form of pharmaceuticals. Intellectual property rights and benefit-sharing arrangements are important issues in ethnobotany; the idea of ethnobotany was first proposed by the early 20th century botanist John William Harshberger. While Harshberger did perform ethnobotanical research extensively, including in areas such as North Africa, Mexico and Pennsylvania, it was not until Richard Evans Schultes began his trips into the Amazon that ethnobotany become a more well known science.
However, the practice of ethnobotany is thought to have much earlier origins in the first century AD when a Greek physician by the name of Pedanius Dioscorides wrote an extensive botanical text detailing the medical and culinary properties of "over 600 mediterranean plants" named De Materia Medica. Historians note that Dioscorides wrote about traveling throughout the Roman empire, including regions such as "Greece, Crete and Petra", in doing so obtained substantial knowledge about the local plants and their useful properties. European botanical knowledge drastically expanded once the New World was discovered due to ethnobotany; this expansion in knowledge can be attributed to the substantial influx of new plants from the Americas, including crops such as potatoes, peanuts and tomatoes. One French explorer in the 16th century, Jacques Cartier, learned a cure for scurvy from a local Iroquois tribe. During the medieval period, ethnobotanical studies were found connected with monasticism. Notable at this time was Hildegard von Bingen.
However, most botanical knowledge was kept in gardens such as physic gardens attached to hospitals and religious buildings. It was thought of in practical use terms for culinary and medical purposes and the ethnographic element was not studied as a modern anthropologist might approach ethnobotany today. Carl Linnaeus carried out in 1732 a research expedition in Scandinavia asking the Sami people about their ethnological usage of plants; the age of enlightenment saw a rise in economic botanical exploration. Alexander von Humboldt collected data from the New World, James Cook's voyages brought back collections and information on plants from the South Pacific. At this time major botanical gardens were started, for instance the Royal Botanic Gardens, Kew in 1759; the directors of the gardens sent out gardener-botanist explorers to care for and collect plants to add to their collections. As the 18th century became the 19th, ethnobotany saw expeditions undertaken with more colonial aims rather than trade economics such as that of Lewis and Clarke which recorded both plants and the peoples encountered use of them.
Edward Palmer collected material culture artifacts and botanical specimens from people in the North American West and Mexico from the 1860s to the 1890s. Through all of this research, the field of "aboriginal botany" was established—the study of all forms of the vegetable world which aboriginal peoples use for food, textiles and more; the first individual to study the emic perspective of the plant world was a German physician working in Sarajevo at the end of the 19th century: Leopold Glück. His published work on traditional medical uses of plants done by rural people in Bosnia has to be considered the first modern ethnobotanical work. Other scholars analyzed uses of plants under an indigenous/local perspective in the 20th century: Matilda Coxe Stevenson, Zuni plants. In the beginning, ethonobotanical specimens and studies were not reliable and sometimes not helpful; this is because the anthropologists did not always collaborate in their work. The botanists focused on identifying species and how the plants were used instead of concentrating upon how plants fit into people's lives.
On the other hand, anthropologists were interested in the cultural role of plants and treated other scientific aspects superficially. In the early 20th century and anthropologists better collaborated and the collection of reliable, detailed cross-disciplinary data began. Beginning in the 20th century, the field of ethnobotany experienced a shift from the raw compilation of data to a greater methodological and conceptual reorientation; this is the beginning of academic ethnobotany. The so-called "father" of this discipline is Richard Evans Schultes though he did not coin the term "ethnobotany". Today the field of ethnobotany requires a variety of skills: botanical training for the identification and preservation of plant specimens. Mark Plotkin, who studied at Harvard University, the Yale School of Forestry and Tufts University, has contributed a number of books on ethnobotany, he completed a
The egg cell, or ovum, is the female reproductive cell in oogamous organisms. The egg cell is not capable of active movement, it is much larger than the motile sperm cells; when egg and sperm fuse, a diploid cell is formed, which grows into a new organism. While the non-mammalian animal egg was obvious, the doctrine ex ovo omne vivum, associated with William Harvey, was a rejection of spontaneous generation and preformationism as well as a bold assumption that mammals reproduced via eggs. Karl Ernst von Baer discovered the mammalian ovum in 1827, Edgar Allen discovered the human ovum in 1928; the fusion of spermatozoa with ova was observed by Oskar Hertwig in 1876. In animals, egg cells are known as ova; the term ovule in animals is used for the young ovum of an animal. In vertebrates, ova are produced by female gonads called ovaries. A number of ova mature via oogenesis. White et al. disproved the longstanding dogma. The team from the Vincent Center for Reproductive Biology, Boston showed that oocyte formation takes place in ovaries of reproductive-age women.
This report challenged a fundamental belief, held since the 1950s, that female mammals are born with a finite supply of eggs, depleted throughout life and exhausted at menopause. In all mammals the ovum is fertilized inside the female body; the human ova grow from primitive germ cells. Each of them divides to give secretions of the uterine glands forming a blastocyst; the ovum is one of the largest cells in the human body visible to the naked eye without the aid of a microscope or other magnification device. The human ovum measures 0.1 mm in diameter. Ooplasm is the yolk of the ovum, a cell substance at its center, which contains its nucleus, named the germinal vesicle, the nucleolus, called the germinal spot; the ooplasm consists of the cytoplasm of the ordinary animal cell with its spongioplasm and hyaloplasm called the formative yolk. Mammalian ova contain only a tiny amount of the nutritive yolk, for nourishing the embryo in the early stages of its development only. In contrast, bird eggs contain enough to supply the chick with nutriment throughout the whole period of incubation.
In the oviparous animals the ova develop protective layers and pass through the oviduct to the outside of the body. They are fertilized inside the female body, or outside. After fertilization, an embryo develops, it hatches from the egg, outside the mother's body. See egg for a discussion of eggs of oviparous animals; the egg cell's cytoplasm and mitochondria are the sole means the egg is able to reproduce by mitosis and form a blastocyst after fertilization. There is an intermediate form, the ovoviviparous animals: the embryo develops within and is nourished by an egg as in the oviparous case, but it hatches inside the mother's body shortly before birth, or just after the egg leaves the mother's body; some fish and many invertebrates use this technique. Nearly all land plants have alternating haploid generations. Gametes are produced by the gametophyte, the haploid generation; the female gametophyte produces structures called archegonia, the egg cells form within them via mitosis. The typical bryophyte archegonium consists of a long neck with a wider base containing the egg cell.
Upon maturation, the neck opens to allow sperm cells to swim into the archegonium and fertilize the egg. The resulting zygote gives rise to an embryo, which will grow into a new diploid individual. In seed plants, a structure called ovule; the gametophyte produces an egg cell. After fertilization, the ovule develops into a seed containing the embryo. In flowering plants, the female gametophyte has been reduced to just eight cells inside the ovule; the gametophyte cell closest to the micropyle opening of the ovule develops into the egg cell. Upon pollination, a pollen tube delivers sperm into the gametophyte and one sperm nucleus fuses with the egg nucleus; the resulting zygote develops into an embryo inside the ovule. The ovule in turn develops into a seed and in many cases the plant ovary develops into a fruit to facilitate the dispersal of the seeds. Upon germination, the embryo grows into a seedling. In the moss Physcomitrella patens, the Polycomb protein FIE is expressed in the unfertilised egg cell as the blue colour after GUS staining reveals.
Soon after fertilisation the FIE gene is inactivated in the young embryo. In algae, the egg cell is called oosphere. Drosophila oocytes develop in individual egg chambers that are supported by nurse cells and surrounded by somatic follicle cells; the nurse cells are large polyploid cells that synthesize and transfer RNA, proteins and organelles to the oocytes. This transfer is followed by the programmed cell death of the nurse cells. During the course of oogenesis, 15 nurse cells die for every oocyte, produced. In addition to this developmentally regulated cell death, egg cells may undergo apoptosis in response to starvation and other insults; the Ova
The order Salviniales is an order of ferns in the class Polypodiopsida. Salviniales are all aquatic and differ from all other ferns in being heterosporous, meaning that they produce two different types of spores that develop into two different types of gametophytes, in that their gametophytes are endosporic, meaning that they never grow outside the spore wall and cannot become larger than the spores that produced them; the megasporangia each produce a single megaspore. In being heterosporus with endosporic gametophytes they are more similar to seed plants than to other ferns; the fertile and sterile leaves are dimorphic, taking on a different shape, leaves bear anastomosing veins. Aerenchyma is present in roots and petioles; the ferns of this order vary radically in form from one another and do not look fern-like. Species of the family Salviniaceae are natant. However, the natant species may temporarily grow on wet mud during times of low water, the Marsileaceae may grow as emergent species, depending on species and location.
The group has the smallest known genomes of all ferns. One genus, Azolla, is amongst the fastest growing plants on earth and caused a cooling of the climate in the Azolla event about 50 million years ago. There is a well-known fossil member of the Marsileales, Hydropteris. In the molecular phylogenetic classification of Smith et al. in 2006, the Salviniales were placed in the leptosporangiate ferns, class Polypodiopsida. Two families and Salviniaceae, were recognized; the linear sequence of Christenhusz et al. intended for compatibility with the classification of Chase and Reveal which placed all land plants in Equisetopsida, reclassified Smith's Polypodiopsida as subclass Polypodiidae and placed the Salviniales there. The circumscription of the order and its families was not changed, that circumscription and placement in Polypodiidae has subsequently been followed in the classifications of Christenhusz and Chase and PPG I; the phylogenic relationships between the two families and five genera of the Salviniales are shown in the following diagram.
C. Michael Hogan. 2010. Fern. Encyclopedia of Earth. National council for Science and the Environment. Washington, DC
Glossary of plant morphology
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens; this page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, organized by plant anatomy and function in plant physiology; this glossary includes terms that deal with vascular plants flowering plants. Non-vascular plants, with their different evolutionary background, tend to have separate terminology. Although plant morphology is integrated with plant anatomy, the former became the basis of the taxonomic description of plants that exists today, due to the few tools required to observe.
Many of these terms date back including Theophrastus. Thus, they have Greek or Latin roots; these terms have been modified and added to over the years, different authorities may not always use them the same way. This page has two parts: The first deals with general plant terms, the second with specific plant structures or parts. Abaxial – located on the side facing away from the axis. Adaxial – located on the side facing towards the axis. Dehiscent – opening at maturity Gall – outgrowth on the surface caused by invasion by other lifeforms, such as parasites Indehiscent – not opening at maturity Reticulate – web-like or network-like Striated – marked by a series of lines, grooves, or ridges Tesselate – marked by a pattern of polygons rectangles Wing – any flat surfaced structure emerging from the side or summit of an organ. Plant habit refers to the overall shape of a plant, it describes a number of components such as stem length and development, branching pattern, texture. While many plants fit neatly into some main categories, such as grasses, shrubs, or trees, others can be more difficult to categorise.
The habit of a plant provides important information about its ecology: that is, how it has adapted to its environment. Each habit indicates a different adaptive strategy. Habit is associated with the development of the plant; as such, it may change as the plant is more properly called its growth habit. In addition to shape, habit indicates plant structure; each plant commences its growth as a herbaceous plant. Plants that remain herbaceous are shorter and seasonal, dying back at the end of their growth season. Woody plants (such as trees and woody vines will acquire woody tissues, which provide strength and protection for the vascular system, they tend to be tall and long lived; the formation of woody tissue is an example of secondary growth, a change in existing tissues, in contrast to primary growth that creates new tissues, such as the elongating tip of a plant shoot. The process of wood formation is commonest in the Spermatophytes and has evolved independently a number of times; the roots may lignify, aiding in the role of supporting and anchoring tall plants, may be part of a descriptor of the plant's habit.
Plant habit can refer to whether the plant possesses any specialised systems for the storage of carbohydrates or water, allowing the plant to renew its growth after an unfavourable period. Where the amount of water stored is high, the plant is referred to as a succulent; such specialised plant parts may arise from the roots. Examples include plants growing in unfavourable climates dry climates where storage is intermittent depending on climatic conditions, those adapted to surviving fires and regrowing from the soil afterwards; some types of plant habit include: Herbaceous plants: A plant whose structures above the surface of the soil, vegetative or reproductive, die back at the end of the annual growing season, never become woody. While these structures are annual in nature, the plant itself may be biannual, or perennial. Herbaceous plants that survive for more than one season possess underground storage organs, thus are referred to as geophytes. Terms used in describing plant habit, include: Acaulescent – the leaves and inflorescence rise from the ground, appear to have no stem.
They are known as rosette forms, some of the many conditions that result from short internodes (i.e. close distances between nodes on the plant stem. See radical, where leaves arise without stems. Acid plant – plants with acid saps due to the production of ammonium salts Acme – the time when the plant or population has its maximum vigor. Actinomorphic – parts of plants that are radially symmetrical in arrangement. Arborescent – growing into a tree-like habit with a single woody stem. Ascending – growing uprightly, in an upward direction. Assurgent – growth ascending. Branching – dividing into multiple smaller segments. Caducous – falling away early. Caulescent – with a well-developed stem above ground. Cespitose – forming dense tufts applied to small plants growing into mats, tufts, or clumps. Creeping – growing along the ground and producing roots at intervals along the surface. Deciduous – falling away after its function is completed. Decumbent – growth starts off prostrate and the ends turn upr
Phytogeography or botanical geography is the branch of biogeography, concerned with the geographic distribution of plant species and their influence on the earth's surface. Phytogeography is concerned with all aspects of plant distribution, from the controls on the distribution of individual species ranges to the factors that govern the composition of entire communities and floras. Geobotany, by contrast, focuses on the geographic space's influence on plants. Phytogeography is part of a more general science known as biogeography. Phytogeographers are concerned with patterns and process in plant distribution. Most of the major questions and kinds of approaches taken to answer such questions are held in common between phyto- and zoogeographers. Phytogeography in wider sense encompasses four fields, according with the focused aspect, flora and origin, respectively: plant ecology. Historical plant geography Phytogeography is divided into two main branches: ecological phytogeography and historical phytogeography.
The former investigates the role of current day biotic and abiotic interactions in influencing plant distributions. The basic data elements of phytogeography are occurrence records with operational geographic units such as political units or geographical coordinates; these data are used to construct phytogeographic provinces and elements. The questions and approaches in phytogeography are shared with zoogeography, except zoogeography is concerned with animal distribution rather than plant distribution; the term phytogeography. How the term is applied by practicing scientists is apparent in the way periodicals use the term; the American Journal of Botany, a monthly primary research journal publishes a section titled "Systematics and Evolution." Topics covered in the American Journal of Botany's "Systematics and Phytogeography" section include phylogeography, distribution of genetic variation and, historical biogeography, general plant species distribution patterns. Biodiversity patterns are not covered.
Phytogeography has a long history. One of the subjects earliest proponents was Prussian naturalist Alexander von Humboldt, referred to as the "father of phytogeography". Von Humboldt advocated a quantitative approach to phytogeography that has characterized modern plant geography. Gross patterns of the distribution of plants became apparent early on in the study of plant geography. For example, Alfred Russel Wallace, co-discoverer of the principle of natural selection, discussed the Latitudinal gradients in species diversity, a pattern observed in other organisms as well. Much research effort in plant geography has since been devoted to understanding this pattern and describing it in more detail. In 1890, the United States Congress passed an act that appropriated funds to send expeditions to discover the geographic distributions of plants in the United States; the first of these was The Death Valley Expedition, including Frederick Vernon Coville, Frederick Funston, Clinton Hart Merriam, others.
Research in plant geography has been directed to understanding the patterns of adaptation of species to the environment. This is done chiefly by describing geographical patterns of trait/environment relationships; these patterns termed ecogeographical rules when applied to plants represent another area of phytogeography. A new field termed macroecology has developed, which focuses on broad-scale patterns and phenomena in ecology. Macroecology focuses as much on other organisms as plants. Floristics is a study of the flora of some area. Traditional phytogeography concerns itself with floristics and floristic classification, see floristic province. Biogeography Botany Geobotanical prospecting Macroecology Species distribution Zoogeography Association Brown, James H.. "Chapter 1". Biogeography. Sunderland, Massachusetts: Sinauer Associates. ISBN 0878930736. Humbodlt, Alexander von. Essai sur la geographie des plantes. Accompagné d'un tableau physique des régions équinoxiales fondé sur des mesures exécutées, depuis le dixiéme degré de latitude boréale jusqu'au dixiéme degré de latitude australe, pendant les années 1799, 1800, 1801, 1802 et 1803.
Paris: Schöll. Polunin, Nicholas. Introduction to Plant Geography and Some Related Sciences. McGraw-Hill. Wallace, Alfred R.. Tropical Nature, Other Essays. London: Macmillan. Clements, Frederic E.. "Plant Geography". Encyclopedia Americana. "Distribution of Plants". New International Encyclopedia. 1905
Bryology is the branch of botany concerned with the scientific study of bryophytes. Bryologists are people who have an active interest in observing, classifying or researching bryophytes; the field is studied along with lichenology due to the similar appearance and ecological niche of the two organisms though bryophytes and lichens are not classified in the same kingdom. Bryophytes were first studied in detail in the 18th century; the German botanist Johann Jacob Dillenius was a professor at Oxford and in 1717 produced the work "Reproduction of the ferns and mosses." The beginning of bryology belongs to the work of Johannes Hedwig, who clarified the reproductive system of mosses and arranged a taxonomy. Areas of research include bryophyte taxonomy, bryophytes as bioindicators, DNA sequencing, the interdependency of bryophytes and other plant and animal species. Among other things, scientists have discovered parasitic bryophytes such as Cryptothallus and carnivorous liverworts such as Colura zoophaga and Pleurozia.
Centers of research in bryology include the University of Bonn in Germany, the University of Helsinki in Finland and the New York Botanical Garden. Miles Joseph Berkeley Elizabeth Gertrude Britton Margaret Sibella Brown Heinrich Christian Funck Robert Kaye Greville Wilhelm Theodor Gümbel Inez M. Haring Hiroshi Inoue Mary S. Taylor Carl Friedrich Warnstorf Meylania, Zeitschrift für Bryologie und Lichenologie Limprichtia, Zeitschrift der Bryologischen Arbeitsgemeinschaft Deutschlands Bryologie at the University of Bonn A Short History of Bryology International Association of Bryologists American Bryological and Lichenological Society British Bryological Society
Algae is an informal term for a large, diverse group of photosynthetic eukaryotic organisms that are not closely related, is thus polyphyletic. Including organisms ranging from unicellular microalgae genera, such as Chlorella and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata and phloem, which are found in land plants; the largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example and the stoneworts. No definition of algae is accepted. One definition is that algae "have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells". Although cyanobacteria are referred to as "blue-green algae", most authorities exclude all prokaryotes from the definition of algae.
Algae constitute a polyphyletic group since they do not include a common ancestor, although their plastids seem to have a single origin, from cyanobacteria, they were acquired in different ways. Green algae are examples of algae that have primary chloroplasts derived from endosymbiotic cyanobacteria. Diatoms and brown algae are examples of algae with secondary chloroplasts derived from an endosymbiotic red alga. Algae exhibit a wide range of reproductive strategies, from simple asexual cell division to complex forms of sexual reproduction. Algae lack the various structures that characterize land plants, such as the phyllids of bryophytes, rhizoids in nonvascular plants, the roots and other organs found in tracheophytes. Most are phototrophic, although some are mixotrophic, deriving energy both from photosynthesis and uptake of organic carbon either by osmotrophy, myzotrophy, or phagotrophy; some unicellular species of green algae, many golden algae, euglenids and other algae have become heterotrophs, sometimes parasitic, relying on external energy sources and have limited or no photosynthetic apparatus.
Some other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids, but are not traditionally considered as algae. Algae have photosynthetic machinery derived from cyanobacteria that produce oxygen as a by-product of photosynthesis, unlike other photosynthetic bacteria such as purple and green sulfur bacteria. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago. The singular alga retains that meaning in English; the etymology is obscure. Although some speculate that it is related to Latin algēre, "be cold", no reason is known to associate seaweed with temperature. A more source is alliga, "binding, entwining"; the Ancient Greek word for seaweed was φῦκος, which could mean either the seaweed or a red dye derived from it. The Latinization, fūcus, meant the cosmetic rouge; the etymology is uncertain, but a strong candidate has long been some word related to the Biblical פוך, "paint", a cosmetic eye-shadow used by the ancient Egyptians and other inhabitants of the eastern Mediterranean.
It could be any color: black, green, or blue. Accordingly, the modern study of marine and freshwater algae is called either phycology or algology, depending on whether the Greek or Latin root is used; the name Fucus appears in a number of taxa. The algae contain chloroplasts. Chloroplasts contain circular DNA like that in cyanobacteria and are interpreted as representing reduced endosymbiotic cyanobacteria. However, the exact origin of the chloroplasts is different among separate lineages of algae, reflecting their acquisition during different endosymbiotic events; the table below describes the composition of the three major groups of algae. Their lineage relationships are shown in the figure in the upper right. Many of these groups contain some members; some retain plastids, but not chloroplasts. Phylogeny based on plastid not nucleocytoplasmic genealogy: Linnaeus, in Species Plantarum, the starting point for modern botanical nomenclature, recognized 14 genera of algae, of which only four are considered among algae.
In Systema Naturae, Linnaeus described the genera Volvox and Corallina, a species of Acetabularia, among the animals. In 1768, Samuel Gottlieb Gmelin published the Historia Fucorum, the first work dedicated to marine algae and the first book on marine biology to use the new binomial nomenclature of Linnaeus, it included elaborate illustrations of seaweed and marine algae on folded leaves. W. H. Harvey and Lamouroux were the first to divide macroscopic algae into four divisions based on their pigmentation; this is the first use of a biochemical criterion in plant systematics. Harvey's four divisions are: red algae, brown algae, green algae, Diatomaceae. At this time, microscopic algae were discovered and reported by a different group of workers studying the Infusoria. Unlike macroalgae, which were viewed as plants, microalgae were considered animals because they are motile; the nonmotile microalgae were sometimes seen as stages of the lifecycle of plants, macroalgae, or animals. Although used as a taxonomic category in some pre-D