1.
Alternation of generations
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In these groups, a multicellular gametophyte, which is haploid with n chromosomes, alternates with a multicellular sporophyte, which is diploid with 2n chromosomes, made up of n pairs. A mature sporophyte produces spores by meiosis, a process which reduces the number of chromosomes to half, the haploid spores germinate and grow into a haploid gametophyte. At maturity, the gametophyte produces gametes by mitosis, which does not alter the number of chromosomes, two gametes fuse to produce a zygote, which develops into a diploid sporophyte. This cycle, from gametophyte to gametophyte, is the way in all land plants. The relationship between the sporophyte and gametophyte varies among different groups of plants, in those algae which have alternation of generations, the sporophyte and gametophyte are separate independent organisms, which may or may not have a similar appearance. In liverworts, mosses and hornworts, the sporophyte is less developed than the gametophyte and is largely dependent on it. In ferns the gametophyte is a small flattened autotrophic prothallus on which the sporophyte is briefly dependent for its nutrition. In flowering plants, the reduction of the gametophyte is much more extreme, a mature animal is diploid and so is, in one sense, equivalent to a sporophyte. However, an animal directly produces haploid gametes by meiosis, no haploid spores capable of dividing are produced, so neither is a haploid gametophyte. There is no alternation between diploid and haploid forms, Life cycles of plants and algae with alternating haploid and diploid multicellular stages are referred to as diplohaplontic. Life cycles, such as those of animals, in there is only a diploid multicellular stage are referred to as diplontic. Life cycles in which there is only a haploid multicellular stage are referred to as haplontic, alternation of generations is defined as the alternation of multicellular diploid and haploid forms in the organisms life cycle, regardless of whether or not these forms are free-living. The free-swimming, haploid gametes form a zygote which germinates into a multicellular diploid sporophyte. The sporophyte produces free-swimming haploid spores by meiosis that germinate into haploid gametophytes, however, in some other groups, either the sporophyte or the gametophyte is very much reduced and is incapable of free living. For example, in all bryophytes the gametophyte generation is dominant, by contrast, in all modern vascular land plants the gametophytes are strongly reduced, although the fossil evidence indicates that they were derived from isomorphic ancestors. In seed plants, the gametophyte develops totally within the sporophyte which protects and nurtures it. The pollen grains, which are the male gametophytes, are reduced to only a few cells, here the notion of two generations is less obvious, as Bateman & Dimichele say porophyte and gametophyte effectively function as a single organism. The alternative term alternation of phases may then be more appropriate, debates about alternation of generations in the early twentieth century can be confusing because various ways of classifying generations co-exist
2.
Plant
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Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. The term is generally limited to the green plants, which form an unranked clade Viridiplantae. This includes the plants, conifers and other gymnosperms, ferns, clubmosses, hornworts, liverworts, mosses and the green algae. Green plants have cell walls containing cellulose and obtain most of their energy from sunlight via photosynthesis by primary chloroplasts and their chloroplasts contain chlorophylls a and b, which gives them their green color. Some plants are parasitic and have lost the ability to produce amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although reproduction is also common. There are about 300–315 thousand species of plants, of which the great majority, green plants provide most of the worlds molecular oxygen and are the basis of most of Earths ecologies, especially on land. Plants that produce grains, fruits and vegetables form humankinds basic foodstuffs, Plants play many roles in culture. They are used as ornaments and, until recently and in variety, they have served as the source of most medicines. The scientific study of plants is known as botany, a branch of biology, Plants are one of the two groups into which all living things were traditionally divided, the other is animals. The division goes back at least as far as Aristotle, who distinguished between plants, which generally do not move, and animals, which often are mobile to catch their food. Much later, when Linnaeus created the basis of the system of scientific classification. Since then, it has become clear that the plant kingdom as originally defined included several unrelated groups, however, these organisms are still often considered plants, particularly in popular contexts. When the name Plantae or plant is applied to a group of organisms or taxon. The evolutionary history of plants is not yet settled. Those which have been called plants are in bold, the way in which the groups of green algae are combined and named varies considerably between authors. Algae comprise several different groups of organisms which produce energy through photosynthesis, most conspicuous among the algae are the seaweeds, multicellular algae that may roughly resemble land plants, but are classified among the brown, red and green algae. Each of these groups also includes various microscopic and single-celled organisms
3.
Algae
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Algae is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as Chlorella and the diatoms, to forms, such as the giant kelp. Most are aquatic and autotrophic and lack many of the cell and tissue types, such as stomata, xylem, and phloem. No definition of algae is generally accepted, one definition is that algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. Some authors exclude all prokaryotes thus do not consider cyanobacteria as algae, Algae constitute a polyphyletic group since they do not include a common ancestor, and 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 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, and the roots, leaves, 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 other heterotrophic organisms, such as the apicomplexans, are derived from cells whose ancestors possessed plastids. Fossilized filamentous algae from the Vindhya basin have been dated back to 1.6 to 1.7 billion years ago, the singular alga is the Latin word for seaweed and retains that meaning in English. Although some speculate that it is related to Latin algēre, be cold, a more likely 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 primarily the cosmetic rouge. It could be any color, black, red, green, 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, most algae contain chloroplasts that are similar in structure to cyanobacteria. Chloroplasts contain circular DNA like that in cyanobacteria and presumably represent 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 groups of algae. Their lineage relationships are shown in the figure in the upper right, many of these groups contain some members that are no longer photosynthetic
4.
Spore
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In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavorable conditions. Spores form part of the cycles of many plants, algae, fungi. Bacterial spores are not part of a sexual cycle but are resistant structures used for survival under unfavourable conditions, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, two gametes fuse to form a zygote which develops into a new sporophyte. This cycle is known as alternation of generations, the term spore derives from the ancient Greek word σπορά spora, meaning seed, sowing, related to σπόρος sporos, sowing, and σπείρειν speirein, to sow. Spores germinate to give rise to haploid gametophytes, while seeds germinate to give rise to diploid sporophytes, vascular plant spores are always haploid. Vascular plants are either homosporous or heterosporous, plants that are homosporous produce spores of the same size and type. Spores can be classified in several ways, In fungi and fungus-like organisms, spores are often classified by the structure in which meiosis, since fungi are often classified according to their spore-producing structures, these spores are often characteristic of a particular taxon of the fungi. Sporangiospores, spores produced by a sporangium in many such as zygomycetes. Zygospores, spores produced by a zygosporangium, characteristic of zygomycetes, ascospores, spores produced by an ascus, characteristic of ascomycetes. Basidiospores, spores produced by a basidium, characteristic of basidiomycetes, aeciospores, spores produced by an aecium in some fungi such as rusts or smuts. Urediniospores, spores produced by a uredinium in some such as rusts or smuts. Teliospores, spores produced by a telium in some such as rusts or smuts. Oospores, spores produced by an oogonium, characteristic of oomycetes, carpospores, spores produced by a carposporophyte, characteristic of red algae. Tetraspores, spores produced by a tetrasporophyte, characteristic of red algae, chlamydospores, thick-walled resting spores of fungi produced to survive unfavorable conditions. Parasitic fungal spores may be classified into internal spores, which germinate within the host, meiospores, spores produced by meiosis, they are thus haploid, and give rise to a haploid daughter cell or a haploid individual. Examples are the cells of gametophytes of seed plants found in flowers or cones. Microspores, meiospores that give rise to a male gametophyte, megaspores, meiospores that give rise to a female gametophyte
5.
Plant reproductive morphology
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Plant reproductive morphology is the study of the physical form and structure of those parts of plants directly or indirectly concerned with sexual reproduction. Among all living organisms, flowers, which are the structures of angiosperms, are the most varied physically. Plants that are not flowering plants also have complex interplays between morphological adaptation and environmental factors in their sexual reproduction, christian Konrad Sprengel studied the reproduction of flowering plants and for the first time it was understood that the pollination process involved both biotic and abiotic interactions. Charles Darwins theories of natural selection utilized this work to build his theory of evolution, Plants have complex lifecycles involving alternation of generations. One generation, the sporophyte, gives rise to the next generation asexually via spores, spores may be identical isospores or come in different sizes, but strictly speaking, spores and sporophytes are neither male nor female because they do not produce gametes. The alternate generation, the gametophyte, produces gametes, eggs and/or sperm, a gametophyte can be be monoicous, producing both eggs and sperm or dioicous, either female or male. In the bryophytes, the gametophyte is the dominant generation. In ferns and seed plants the sporophyte is the dominant generation, the obvious visible plant, whether a small herb or a large tree, is the sporophyte, and the gametophyte is very small. In seed plants, each female gametophyte, and the spore that gives rise to it, is hidden within the sporophyte and is dependent on it for nutrition. Each male gametophyte consists of from two to four cells enclosed within the protective wall of a pollen grain. The sporophyte of a plant is often described using sexual terms based on the sexuality of the gametophyte it gives rise to. For example, a sporophyte that produces spores that give rise only to male gametophytes may be described as male, even though the sporophyte itself is asexual, producing only spores. Similarly, flowers produced by the sporophyte may be described as unisexual or bisexual, the flower is the characteristic structure concerned with sexual reproduction in flowering plants. Flowers vary enormously in their construction, a complete flower, like that of Ranunculus glaberrimus shown in the figure, has a calyx of outer sepals and a corolla of inner petals. The sepals and petals form the perianth. Next inwards there are numerous stamens, which produce pollen grains, stamens may be called the male parts of a flower and collectively form the androecium. Finally in the middle there are carpels, which at maturity one or more ovules. Carpels may be called the parts of a flower and collectively form the gynoecium
6.
Red algae
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The red algae, or Rhodophyta, are one of the oldest groups of eukaryotic algae. The Rhodophyta also contains one of the largest phyla of algae, the majority of species are found in the Florideophyceae, and consist of mostly multicellular, marine algae, including many notable seaweeds. Approximately 5% of the red algae occur in freshwater environments, red algae store sugars as floridean starch, which is a type of starch that consists of highly branched amylopectin without amylose, as food reserves outside their plastids. Most red algae are multicellular, macroscopic, marine. The red algal life history is typically an alternation of generations that may have three rather than two. Chloroplasts evolved following an event between an ancestral, photosynthetic cyanobacterium and an early eukarytoic Phagotroph. This event resulted in the origin of the red and Green algae, and the Glaucophytes, a secondary endosymbiosis event involving an ancestral red alga and a heterotrophic eukaryote resulted in the evolution and diversification of several other photosynthetic lineages. The coralline algae, which secrete calcium carbonate and play a role in building coral reefs. Red algae such as dulse and laver are a part of European and Asian cuisines and are used to make other products such as agar, carrageenans. Unicellular members of the Cyanidiophyceae are thermoacidophiles and are found in hot springs. The remaining taxa are found in marine and freshwater environments, most rhodophytes are marine with a worldwide distribution, and are often found at greater depths compared to other seaweeds because of dominance in certain pigments within their chloroplasts. Some marine species are found on sandy shores, while most others can be attached to rocky substrata. A few freshwater species are found in waters with sandy bottoms. Bangiomorpha pubescens, a fossil from arctic Canada, strongly resembles the modern red alga Bangia despite occurring in rocks dating to 1.2 billion years ago. Two kinds of fossils resembling red algae were found sometime between 2006 and 2011 in well-preserved sedimentary rocks in Chitrakoot, central India, red algae are important builders of limestone reefs. The earliest such coralline algae, the solenopores, are known from the Cambrian period, other algae of different origins filled a similar role in the late Paleozoic, and in more recent reefs. Calcite crusts that have been interpreted as the remains of red algae. Thallophytes resembling coralline red algae are known from the late Proterozoic Doushantuo formation, in the system of Adl et al
7.
Embryophyte
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The Embryophyta are the most familiar group of green plants that form vegetation on earth. Living embryophytes include hornworts, liverworts, mosses, ferns, lycophytes, gymnosperms and flowering plants, the Embryophyta are informally called land plants because they live primarily in terrestrial habitats, while the related green algae are primarily aquatic. All are complex multicellular eukaryotes with specialized reproductive organs, the name derives from their innovative characteristic of nurturing the young embryo sporophyte during the early stages of its multicellular development within the tissues of the parent gametophyte. With very few exceptions, embryophytes obtain their energy by photosynthesis, the evolutionary origins of the embryophytes are discussed further below, but they are believed to have evolved from within a group of complex green algae during the Paleozoic era. Charales or the stoneworts may be the best living illustration of that developmental step, embryophytes are primarily adapted for life on land, although some are secondarily aquatic. Accordingly, they are called land plants or terrestrial plants. On a microscopic level, the cells of embryophytes are broadly similar to those of green algae and they are eukaryotic, with a cell wall composed of cellulose and plastids surrounded by two membranes. Embryophyte cells also generally have a central vacuole enclosed by a vacuolar membrane or tonoplast. In common with all groups of multicellular algae they have a cycle which involves alternation of generations. The mature sporophyte produces spores which grow into a gametophyte. Embryophytes have two related to their reproductive cycles which distinguish them from all other plant lineages. Firstly, their gametophytes produce sperm and eggs in multicellular structures and this second feature is the origin of the term embryophyte – the fertilized egg develops into a protected embryo, rather than dispersing as a single cell. In the bryophytes the sporophyte dependent on the gametophyte, while in all other embryophytes the sporophyte generation is dominant. Embryophytes also differ from algae by having metamers, metamers are repeated units of development, in which each unit derives from a single cell, but the resulting product tissue or part is largely the same for each cell. The whole organism is thus constructed from similar, repeating parts or metamers, accordingly, these plants are sometimes termed metaphytes and classified as the group Metaphyta. All green algae and land plants are now known to form an evolutionary lineage or clade. According to several molecular clock estimates the Viridiplantae split 1,200 million years ago to 725 million years ago into two clades, chlorophytes and streptophytes, the chlorophytes are considerably more diverse and were originally marine, although some groups have since spread into fresh water. The streptophyte algae are less diverse and adapted to fresh very early in their evolutionary history
8.
Bryophyte
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Bryophyte is a traditional name used to refer to all embryophytes that are non-vascular plants, namely the mosses, hornworts, and liverworts, covering around 25,000 species. They are characteristically limited in size and prefer moist habitats although they can survive in drier environments, bryophytes are usually considered to be a paraphyletic group and not a natural group, although some studies have produced contrary results. Regardless of their status, the name is convenient and remains in use as a collective term. Bryophytes produce enclosed reproductive structures, but they produce neither flowers nor seeds, the term bryophyte comes from Greek βρύον, bryon tree-moss, oyster-green + φυτόν – phyton plant. Like all land plants, bryophytes have life cycles with alternation of generations, in each cycle, a haploid gametophyte, each of whose cells contains a fixed number of unpaired chromosomes, alternates with a diploid sporophyte, whose cell contain two sets of paired chromosomes. Gametophytes produce haploid sperm and eggs which fuse to form zygotes that grow into sporophytes. Sporophytes produce haploid spores by meiosis, that grow into gametophytes, bryophytes are gametophyte dominant, meaning that the more prominent, longer-lived plant is the haploid gametophyte. The diploid sporophytes appear only occasionally and remain attached to and nutritionally dependent on the gametophyte, in bryophytes, the sporophytes are always unbranched and produce a single sporangium. Liverworts, mosses and hornworts spend most of their lives as gametophytes, gametangia, archegonia and antheridia, are produced on the gametophytes, sometimes at the tips of shoots, in the axils of leaves or hidden under thalli. Some bryophytes, such as the liverwort Marchantia, create elaborate structures to bear the gametangia that are called gametangiophores, sperm are flagellated and must swim from the antheridia that produce them to archegonia which may be on a different plant. Arthropods can assist in transfer of sperm, fertilized eggs become zygotes, which develop into sporophyte embryos inside the archegonia. Mature sporophytes remain attached to the gametophyte and they consist of a stalk called a seta and a single sporangium or capsule. Inside the sporangium, haploid spores are produced by meiosis and these are dispersed, most commonly by wind, and if they land in a suitable environment can develop into a new gametophyte. Thus bryophytes disperse by a combination of swimming sperm and spores, in a similar to lycophytes, ferns. The arrangement of antheridia and archegonia on an individual plant is usually constant within a species. The main division is between species in which the antheridia and archegonia occur on the plant and those in which they occur on different plants. The term monoicous may be used where antheridia and archegonia occur on the same gametophyte, in seed plants, monoecious is used where flowers with anthers and flowers with ovules occur on the same sporophyte and dioecious where they occur on different sporophytes. These terms occasionally may be used instead of monoicous and dioicous to describe bryophyte gametophytes, monoecious and monoicous are both derived from the Greek for one house, dioecious and dioicous from the Greek for two houses
9.
Moss
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Mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations. Although some species have conducting tissues, these are poorly developed. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores and they are typically 0. 2–10 cm tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm in height, mosses are commonly confused with lichens, hornworts, and liverworts. Lichens may superficially look like mosses, and have names that include the word moss. This contrasts with the pattern in all plants, where the diploid sporophyte generation is dominant. Mosses are now classified on their own as the division Bryophyta, the main commercial significance of mosses is as the main constituent of peat, although they are also used for decorative purposes, such as in gardens and in the florist trade. Traditional uses of mosses included as insulation and for the ability to absorb liquids up to 20 times their weight, botanically, mosses are non-vascular plants in the land plant division Bryophyta. They are small plants that absorb water and nutrients mainly through their leaves and harvest carbon dioxide. They differ from plants in lacking water-bearing xylem tracheids or vessels. As in liverworts and hornworts, the gametophyte generation is the dominant phase of the life cycle. This contrasts with the pattern in all plants, where the diploid sporophyte generation is dominant. Mosses reproduce using spores, not seeds, and have no flowers, Moss gametophytes have stems which may be simple or branched and upright or prostrate. Their leaves are simple, usually only a layer of cells with no internal air spaces. They do not have roots, but have threadlike rhizoids that anchor them to their substrate. Mosses do not absorb water or nutrients from their substrate through their rhizoids and they can be distinguished from liverworts by their multi-cellular rhizoids. Spore-bearing capsules or sporangia of mosses are borne singly on long, unbranched stems, thereby distinguishing them from the polysporangiophytes, the spore-bearing sporophytes are short-lived and dependent on the gametophyte for water supply and nutrition. Also, in most mosses, the capsule enlarges and matures after its stalk elongates
10.
Marchantiophyta
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The Marchantiophyta /mɑːrˌkæntiˈɒfᵻtə/ are 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 and it is estimated that there are about 9000 species of liverworts. Some of the familiar species grow as a flattened leafless thallus. Leafy species can be distinguished from the apparently similar mosses on the basis of a number of features, leafy liverworts also differ from most mosses in that their leaves never have a costa and may bear marginal cilia. Liverworts are typically small, usually from 2–20 mm wide with individual plants less than 10 cm long, 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 habitat, most often in humid locations although there are desert. Some species can be a nuisance in shady greenhouses or a weed in gardens, most liverworts are small, usually from 2–20 millimetres wide with individual plants less than 10 centimetres long, so they are often overlooked. The most familiar liverworts consist of a prostrate, flattened, ribbon-like or branching structure called a thallus, liverworts can most reliably be distinguished from the apparently similar mosses by their single-celled rhizoids. Liverworts have a gametophyte-dominant life cycle, with the dependent on the gametophyte. Cells in a typical liverwort plant each contain only a set of genetic information. This contrasts sharply with the pattern exhibited by all animals. In the more familiar seed plants, the generation is represented only by the tiny pollen. Another unusual feature of the life cycle is that sporophytes are very short-lived. Even in other bryophytes, the sporophyte is persistent and disperses spores over an extended period, the life of a liverwort starts from the germination of a haploid spore to produce a protonema, which is either a mass of thread-like filaments or else a flattened thallus. The protonema is a stage in the life of a liverwort. The male organs are known as antheridia and produce the sperm cells, clusters of antheridia are enclosed by a protective layer of cells called the perigonium. As in other plants, the female organs are known as archegonia and are protected by the thin surrounding perichaetum. Each archegonium has a hollow tube, the neck, down which the sperm swim to reach the egg cell
11.
Antheridium
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An antheridium is a haploid structure or organ producing and containing male gametes. The plural form is antheridia, and a structure containing one or more antheridia is called an androecium, androecium is also used as the collective term for the stamens of flowering plants. Antheridia are present in the phase of cryptogams like bryophytes. Many algae and some fungi, for example ascomycetes and water moulds, in gymnosperms and angiosperms, the male gametophytes have been reduced to pollen grains and in most of these the antheridia have been reduced to a single generative cell within the pollen grain. During pollination, this cell divides and gives rise to sperm cells. The female counterpart to the antheridium in cryptogams is the archegonium, an antheridium typically consists of sterile cells and spermatogenous tissue. The sterile cells may form a support structure or surround the spermatogenous tissue as a protective jacket. The spermatogenous cells give rise to spermatids via mitotic cell division, in some bryophytes, the antheridium is borne on an antheridiophore, a stalk-like structure that carries the antheridium at its apex. Hornworts have antheridia, in some cases arranged within androecia, microsporangia produce spores that give rise to male gametophytes. National council for Science and the Environment
12.
Lycopodiophyta
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The Division Lycopodiophyta is a tracheophyte subgroup of the Kingdom Plantae. It is one of the oldest lineages of extant vascular plants and these species reproduce by shedding spores and have macroscopic alternation of generations, although some are homosporous while others are heterosporous. Most members of Lycopodiophyta bear a protostele, and the generation is dominant. They differ from all other plants in having microphylls, leaves that have only a single vascular trace rather than the much more complex megaphylls found in ferns. There are around 1,290 living species of Lycopodiophyta which are divided into three extant orders, in addition to extinct groups. The extant orders each have a family with a total of 12 genera and 1290 known species. The following phylogram shows a relationship between Lycopodiophyta orders. The following is another phylogram showing the evolution of Lycopodiophytes, note the Cooksonia-like plants and zosterophylls are a paraphyletic grade of stem group Lycopodiophytes. In fact, most known genera are extinct, the Silurian species Baragwanathia longifolia represents the earliest identifiable Lycopodiophyta, while some Cooksonia seem to be related. Lycopodolica is another Silurian genus which appears to be an member of this group. Fossils ascribed to the Lycopodiophyta first appear in the Silurian period, phylogenetic analysis places them at the base of the vascular plants, they are distinguished by their microphylls and by transverse dehiscence of their sporangia. Sporangia of living species are borne on the surfaces of microphylls. In some groups, these sporophylls are clustered into strobili, during the Carboniferous Period, tree-like Lycopodiophyta formed huge forests that dominated the landscape. The complex ecology of tropical rainforests collapsed during the mid Pennsylvanian due to a change in climate. Unlike modern trees, leaves out of the entire surface of the trunk and branches. Their remains formed many coal deposits. In Fossil Park, Glasgow, Scotland, fossilized Lycopodiophyta trees can be found in sandstone, the trees are marked with diamond-shaped scars where they once had leaves. The Lycopodiophyta had their maximum diversity in the Upper Carboniferous, particularly tree-like Lepidodendron and Sigillaria, in Euramerica these became apparently extinct in the Late Pennsylvanian, as a result of a transition to a much drier climate, to give way to conifers, ferns and horsetails
