Carl Linnaeus
Carl Linnaeus known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, his name is rendered in Latin as Carolus Linnæus. Linnaeus was born in the countryside of Småland in southern Sweden, he received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and published the first edition of his Systema Naturae in the Netherlands, he returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals and minerals, while publishing several volumes, he was one of the most acclaimed scientists in Europe at the time of his death. Philosopher Jean-Jacques Rousseau sent him the message: "Tell him I know no greater man on earth."
Johann Wolfgang von Goethe wrote: "With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly." Swedish author August Strindberg wrote: "Linnaeus was in reality a poet who happened to become a naturalist." Linnaeus has been called Princeps botanicorum and "The Pliny of the North". He is considered as one of the founders of modern ecology. In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains comprise the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself. Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707, he was the first child of Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, Emerentia Linnæa, his father taught him Latin as a small child.
One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Samuel Brodersonius. A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, his father Nils became the rector of Stenbrohult; the family moved into the rectory from the curate's house. In his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth. Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson; when Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree, lind in Swedish, that grew on the family homestead.
This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name; the son always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus. Linnaeus's father began teaching him basic Latin and geography at an early age; when Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them". Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus studied going to the countryside to look for plants, he reached the last year of the Lower School when he was fifteen, taught by the headmaster, Daniel Lannerus, interested in botany. Lannerus gave him the run of his garden, he introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan in Växjö.
A botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature, he remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii Chloros Gothica and Rudbeckii Hortus Upsaliensis...."Linnaeus entered the Växjö Katedralskola in 1724, where he studied Greek, Hebrew and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing. Rothman believed otherwise; the doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer. Rothman showed Linnaeus that botany was a serious sub
Vascular plant
Vascular plants known as tracheophytes, form a large group of plants that are defined as those land plants that have lignified tissues for conducting water and minerals throughout the plant. They have a specialized non-lignified tissue to conduct products of photosynthesis. Vascular plants include the clubmosses, ferns and angiosperms. Scientific names for the group include Tracheophyta and Equisetopsida sensu lato; the term higher plants should be avoided as a synonym for vascular plants as it is a remnant of the abandoned concept of the great chain of being. Vascular plants are defined by three primary characteristics: Vascular plants have vascular tissues which distribute resources through the plant; this feature allows vascular plants to evolve to a larger size than non-vascular plants, which lack these specialized conducting tissues and are thereby restricted to small sizes. In vascular plants, the principal generation phase is the sporophyte, which produce spores and is diploid. By contrast, the principal generation phase in non-vascular plants is the gametophyte, which produces gametes and is haploid.
They have true roots and stems if one or more of these traits are secondarily lost in some groups. The formal definition of the division Tracheophyta encompasses both these characteristics in the Latin phrase "facies diploida xylem et phloem instructa". One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spores, enabled the development of the ability to release them higher and to broadcast them farther; such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, more branching. A proposed phylogeny of the vascular plants after Kenrick and Crane is as follows, with modification to the gymnosperms from Christenhusz et al. Pteridophyta from Smith et al. and lycophytes and ferns by Christenhusz et al.
This phylogeny is supported by several molecular studies. Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns are not monophyletic. Water and nutrients in the form of inorganic solutes are drawn up from the soil by the roots and transported throughout the plant by the xylem. Organic compounds such as sucrose produced by photosynthesis in leaves are distributed by the phloem sieve tube elements; the xylem consists of vessels in flowering plants and tracheids in other vascular plants, which are dead hard-walled hollow cells arranged to form files of tubes that function in water transport. A tracheid cell wall contains the polymer lignin; the phloem however consists of living cells called sieve-tube members. Between the sieve-tube members are sieve plates, which have pores to allow molecules to pass through. Sieve-tube members lack such organs as nuclei or ribosomes, but cells next to them, the companion cells, function to keep the sieve-tube members alive.
The most abundant compound in all plants, as in all cellular organisms, is water which serves an important structural role and a vital role in plant metabolism. Transpiration is the main process of water movement within plant tissues. Water is transpired from the plant through its stomata to the atmosphere and replaced by soil water taken up by the roots; the movement of water out of the leaf stomata creates a transpiration pull or tension in the water column in the xylem vessels or tracheids. The pull is the result of water surface tension within the cell walls of the mesophyll cells, from the surfaces of which evaporation takes place when the stomata are open. Hydrogen bonds exist between water molecules; the draw of water upwards may be passive and can be assisted by the movement of water into the roots via osmosis. Transpiration requires little energy to be used by the plant. Transpiration assists the plant in absorbing nutrients from the soil as soluble salts. Living root cells passively absorb water in the absence of transpiration pull via osmosis creating root pressure.
It is possible for there to be no evapotranspiration and therefore no pull of water towards the shoots and leaves. This is due to high temperatures, high humidity, darkness or drought. Xylem and phloem tissues are involved in the conduction processes within plants. Sugars are conducted throughout the plant in the phloem and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves by photosynthesis and transported to the growing shoots and roots for use in growth, cellular respiration or storage. Minerals are transported to the shoots to allow cell division and growth. Fern allies Non-vascular plant “Higher plants” or “vascular plants”
Herbaceous plant
Herbaceous plants are plants that have no persistent woody stem above ground. The term is applied to perennials, but in botany it may refer to annuals or biennials, include both forbs and graminoids. Annual herbaceous plants die at the end of the growing season or when they have flowered and fruited, they grow again from seed. Herbaceous perennial and biennial plants may have stems that die at the end of the growing season, but parts of the plant survive under or close to the ground from season to season. New growth develops from living tissues remaining on or under the ground, including roots, a caudex or various types of underground stems, such as bulbs, stolons and tubers. Examples of herbaceous biennials include carrot and common ragwort. By contrast, non-herbaceous perennial plants are woody plants which have stems above ground that remain alive during the dormant season and grow shoots the next year from the above-ground parts – these include trees and vines; some fast-growing herbaceous plants are pioneers, or early-successional species.
Others form the main vegetation of many stable habitats, occurring for example in the ground layer of forests, or in open habitats such as meadow, salt marsh or desert. Some herbaceous plants can grow rather large, such as the genus Musa; the age of some herbaceous perennial plants can be determined by herbchronology, the analysis of annual growth rings in the secondary root xylem
Flowering plant
The flowering plants known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 64 orders, 416 families 13,164 known genera and c. 369,000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, the production of fruits that contain the seeds. Etymologically, angiosperm means a plant; the term comes from the Greek words sperma. The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago, the first flowering plants are known from 160 mya, they diversified extensively during the Early Cretaceous, became widespread by 120 mya, replaced conifers as the dominant trees from 100 to 60 mya. Angiosperms differ from other seed plants in several ways, described in the table below; these distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants and the most commercially important group to humans.
Angiosperm stems are made up of seven layers. The amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms; the vascular bundles of the stem are arranged such that the phloem form concentric rings. In the dicotyledons, the bundles in the young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles, a complete ring is formed, a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside; the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.
Among the monocotyledons, the bundles are more numerous in the young stem and are scattered through the ground tissue. They once formed the stem increases in diameter only in exceptional cases; the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, provide the most trustworthy external characteristics for establishing relationships among angiosperm species; the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally from the axil of a leaf; as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More the flower-bearing portion of the plant is distinguished from the foliage-bearing or vegetative portion, forms a more or less elaborate branch-system called an inflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to become pollen grains, are the "male" cells and are borne in the stamens.
The "female" cells called megaspores, which will divide to become the egg cell, are contained in the ovule and enclosed in the carpel. The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators; the individual members of these surrounding structures are known as petals. The outer series is green and leaf-like, functions to protect the rest of the flower the bud; the inner series is, in general, white or brightly colored, is more delicate in structure. It functions to attract bird pollinators. Attraction is effected by color and nectar, which may be secreted in some part of the flower; the characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans. While the majority of flowers are perfect or hermaphrodite, flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization.
Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot transfer pollen to the pistil. Homomorphic flowers may employ a biochemical mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers; the botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon and σπέρμα, was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked; the term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any
Gynoecium
Gynoecium is most used as a collective term for the parts of a flower that produce ovules and develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; the gynoecium is referred to as the "female" portion of the flower, although rather than directly producing female gametes, the gynoecium produces megaspores, each of which develops into a female gametophyte which produces egg cells. The term gynoecium is used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses and hornworts; the corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are called carpellate. Flowers lacking a gynoecium are called staminate; the gynoecium is referred to as female because it gives rise to female gametophytes. Gynoecium development and arrangement is important in systematic research and identification of angiosperms, but can be the most challenging of the floral parts to interpret.
The gynoecium may consist of one or more separate pistils. A pistil consists of an expanded basal portion called the ovary, an elongated section called a style and an apical structure that receives pollen called a stigma; the ovary, is the enlarged basal portion which contains placentas, ridges of tissue bearing one or more ovules. The placentas and/or ovule may be born on the gynoecial appendages or less on the floral apex; the chamber in which the ovules develop is called a locule. The style, is a pillar-like stalk; some flowers such as Tulipa do not have a distinct style, the stigma sits directly on the ovary. The style is a hollow tube in some plants such as lilies, or has transmitting tissue through which the pollen tubes grow; the stigma, is found at the tip of the style, the portion of the carpel that receives pollen. It is sticky or feathery to capture pollen; the word "pistil" comes from Latin pistillum meaning pestle. A sterile pistil in a male flower is referred to as a pistillode; the pistils of a flower are considered to be composed of carpels.
A carpel is the female reproductive part of the flower, interpreted as modified leaves bearing structures called ovules, inside which the egg cells form. A pistil may consist of one carpel, with its ovary and stigma, or several carpels may be joined together with a single ovary, the whole unit called a pistil; the gynoecium may consist of one multi-carpellate pistil. The number of carpels is described by terms such as tricarpellate. Carpels are thought to be phylogenetically derived from ovule-bearing leaves or leaf homologues, which evolved to form a closed structure containing the ovules; this structure is rolled and fused along the margin. Although many flowers satisfy the above definition of a carpel, there are flowers that do not have carpels according to this definition because in these flowers the ovule, although enclosed, are borne directly on the shoot apex, only become enclosed by the carpel. Different remedies have been suggested for this problem. An easy remedy that applies to most cases is to redefine the carpel as an appendage that encloses ovule and may or may not bear them.
If a gynoecium has a single carpel, it is called monocarpous. If a gynoecium has multiple, distinct carpels, it is apocarpous. If a gynoecium has multiple carpels "fused" into a single structure, it is syncarpous. A syncarpous gynoecium can sometimes appear much like a monocarpous gynoecium; the degree of connation in a syncarpous gynoecium can vary. The carpels retain separate styles and stigmas; the carpels may be "fused" except for retaining separate stigmas. Sometimes carpels possess distinct ovaries. In a syncarpous gynoecium, the "fused" ovaries of the constituent carpels may be referred to collectively as a single compound ovary, it can be a challenge to determine. If the styles and stigmas are distinct, they can be counted to determine the number of carpels. Within the compound ovary, the carpels may have distinct locules divided by walls called septa. If a syncarpous gynoecium has a single style and stigma and a single locule in the ovary, it may be necessary to examine how the ovules are attached.
Each carpel will have a distinct line of placentation where the ovules are attached. Pistils begin as small primordia on a floral apical meristem, forming than, closer to the apex than sepal and stamen primordia. Morphological and molecular studies of pistil ontogeny reveal that carpels are most homologous to leaves. A carpel has a similar function to a megasporophyll, but includes a stigma, is fused, with ovules enclosed in the enlarged lower portion, the ovary. In some basal angiosperm lineages and Winteraceae, a carpel begins as a shallow cup where the ovules de
Erica
Erica is a genus of 860 species of flowering plants in the family Ericaceae. The English common names heath and heather are shared by some related genera of similar appearance; the genus Calluna was included in Erica – it differs in having smaller scale-leaves, the flower corolla consisting of separate petals. Erica is sometimes referred to as "winter heather" to distinguish it from Calluna "summer heather"; the Latin word erica means "heath" or "broom". It is believed that Pliny adapted erica from Ancient Greek ἐρείκη; the expected Anglo-Latin pronunciation, may be given in dictionaries, but is more heard. Most of the species of Erica are small shrubs from 20 -- 150 cm high. All are evergreen, with needle-like leaves 2 -- 15 millimetres long. Flowers are sometimes axillary, sometimes borne in terminal umbels or spikes, are outward or downward facing; the seeds are small, in some species may survive in the soil for decades. Dulfer published the last revision of the genus Erica in the 1960s. Many new species have subsequently been described and a further 83 have been included in Erica from former “minor genera”, such as Phillipia Klotzsch and Blaeria L.
A more recent overview of Erica species is provided in an electronic identification aid, but a modern taxonomic revision of the genus as a whole is still lacking. A number of detailed phylogenetic hypotheses for Erica have been published based on nuclear ribosomal and plastid DNA sequences; the closest relatives of Erica are Daboecia and Calluna, representing the oldest surviving lineages of a, by inference, ancestrally Palearctic tribe Ericeae. The small number of European Erica species represent the oldest lineages of the genus, within which a single, order-of-magnitude more species-rich, African clade is nested. Within the African clade and Madagascan/Mascarene species represent monophyletic groups. Selected species include: Around 690 of the species are endemic to South Africa, these are called the Cape heaths, forming the largest genus in the fynbos; the remaining species are native to other parts of Africa, the Mediterranean, Europe. Like most Ericaceae, Erica species are calcifuges, being limited to acidic or acidic soils.
In fact, the term "ericaceous" is applied to all calcifuges, to the compost used in their cultivation. Soils range from dry, sandy soils to wet ones such as bog, they dominate dwarf-shrub habitats, or the ground vegetation of open acidic woodland. Plants of this genus are eaten by the larvae of many Lepidoptera species, including emperor moth, garden tiger moth, true lover's knot, wormwood pug, the silver-studded blue, the Coleophora case-bearers C. juncicolella and C. pyrrhulipennella. Some species of sunbirds are known to pollinate Erica. Two such species are the orange-breasted sunbird. Erica species are grown as garden plants for their floral effect, they associate well with conifers and are seen in planting schemes as massed groundcover beneath varieties of dwarf conifers. They are capable of producing flower colour throughout the year, they can be grown in tubs or window boxes to provide interest through autumn and into winter
Sepal
A sepal is a part of the flower of angiosperms. Green, sepals function as protection for the flower in bud, as support for the petals when in bloom; the term sepalum was coined by Noël Martin Joseph de Necker in 1790, derived from the Greek σκεπη, a covering. Collectively the sepals are called the outermost whorl of parts that form a flower; the word calyx was adopted from the Latin calyx, not to be confused with a cup or goblet. Calyx derived from the Greek κάλυξ, a bud, a calyx, a husk or wrapping, while calix derived from the Greek κυλιξ, a cup or goblet, the words have been used interchangeably in botanical Latin. After flowering, most plants have no more use for the calyx which becomes vestigial; some plants retain a thorny calyx, either dried or live, as protection for seeds. Examples include species of Acaena, some of the Solanaceae, the water caltrop, Trapa natans. In some species the calyx not only persists after flowering, but instead of withering, begins to grow until it forms a bladder-like enclosure around the fruit.
This is an effective protection against some kinds of birds and insects, for example in Hibiscus trionum and the Cape gooseberry. Morphologically, both sepals and petals are modified leaves; the calyx and the corolla are the outer sterile whorls of the flower, which together form what is known as the perianth. The term tepal is applied when the parts of the perianth are difficult to distinguish, e.g. the petals and sepals share the same color, or the petals are absent and the sepals are colorful. When the undifferentiated tepals resemble petals, they are referred to as "petaloid", as in petaloid monocots, orders of monocots with brightly coloured tepals. Since they include Liliales, an alternative name is lilioid monocots. Examples of plants in which the term tepal is appropriate include genera such as Tulipa. In contrast, genera such as Rosa and Phaseolus have well-distinguished petals; the number of sepals in a flower is its merosity. Flower merosity is indicative of a plant's classification.
The merosity of a eudicot flower is four or five. The merosity of a monocot or palaeodicot flower is a multiple of three; the development and form of the sepals vary among flowering plants. They may be fused together; the sepals are much reduced, appearing somewhat awn-like, or as scales, teeth, or ridges. Most such structures protrude until the fruit is mature and falls off. Examples of flowers with much reduced perianths are found among the grasses. In some flowers, the sepals are fused towards the base. In other flowers a hypanthium includes the bases of sepals and the attachment points of the stamens. Plant morphology
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