The Division Lycopodiophyta (sometimes called Lycophyta or Lycopods) is a tracheophyte Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms. Scientific names for the group include Tracheophyta and Tracheobionta, but neither name is very widely used.[ subdivision of the Kingdom Plantae Plants are living organisms belonging to the kingdom Plantae. They include familiar organisms such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The scientific study of plants, known as botany, has identified about 350,000 extant species of plants, defined as seed plants, bryophytes, ferns and fern allies. As of 2004,. It is the oldest extant (living) vascular plant Vascular plants are those plants that have lignified tissues for conducting water, minerals, and photosynthetic products through the plant. Vascular plants include the ferns, clubmosses, flowering plants, conifers and other gymnosperms. Scientific names for the group include Tracheophyta and Tracheobionta, but neither name is very widely used.[ division at around 410 million years old,[3]:99 and includes some of the most "primitive" extant species. These species reproduce by shedding spores In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoans. A chief difference between spores and seeds as dispersal units is that spores have very little stored and have macroscopic alternation of generations The Alternation of the generations describes the life cycle of plants, fungi and protists. A multicellular diploid phase alternates with a multicellular haploid phase. The term can be confusing for people familiar only with the life cycle of a typical animal. A more understandable name would be "alternation of phases of a single generation&, although some are homosporous while others are heterosporous In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoans. A chief difference between spores and seeds as dispersal units is that spores have very little stored. Members of Lycopodiophyta bear a protostele, and the sporophyte All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants and in some green algae. For common flowering generation is dominant. [4] They differ from all other vascular plants in having microphylls The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based. The traditional definition of microphylls and megaphylls will be employed in this article for simplicity;, leaves that have only a single vascular trace (vein) rather than the much more complex megaphylls found in ferns A fern is any one of a group of about 12,000 species of plants. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants. Ferns do not have either seeds or flowers (they reproduce via spores) and seed plants The spermatophytes (also known as phanerogams) comprise those plants that produce seeds. They are a subset of the embryophytes or land plants. The living spermatophytes form five groups:.
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Classification
There are around 1,200[5]:8 living species divided into three main groups within the Lycopodiophyta, sometimes separated at the level of order and sometimes at the level of class. These are subdivided at the class level here:
- Class Lycopodiopsida Lycopodiopsida is a class of plants often loosely grouped as the fern allies, and includes the clubmosses. Lycopodiopsida traditionally included all the clubmosses, including Selaginella and Isoetes. However, subdivisions within the Division Lycopodiophyta are now considered ancient enough to warrant higher-level separation in accordance with – clubmosses and firmosses
- Class Isoetopsida The Isoetopsida is a class of the Lycopodiophyta. All living plants belong to the genus Selaginella in the Selaginellales or to Isoetes in the order Isoetales. In the past, members of this group have sometimes been placed in the class Isoetopsida, sometimes in the Selaginellopsida or Lycopodiopsida. There are about 700 species of Selaginella and 14 – quillworts, scale trees, and spikemosses. The spikemosses are sometimes classified under Selaginellopsida.[6]
Evolution
The members of this division have a long evolutionary history, and fossils Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record. The study of fossils across geological time, how are abundant worldwide, especially in coal deposits A deposit account is a current account, savings account, or other type of bank account, at a banking institution that allows money to be deposited and withdrawn by the account holder. These transactions are recorded on the bank's books, and the resulting balance is recorded as a liability for the bank, and represent the amount owed by the bank to. In fact, most known genera In biology, a genus is a low-level taxonomic rank (a taxon) used in the classification of living and fossil organisms, which is an example of definition by genus and differentia. The term comes from Latin genus "descent, family, type, gender", cognate with Greek: γένος – genos, "race, stock, kin" are extinct In biology and ecology, extinction is the end of an organism or group of taxa. The moment of extinction is generally considered to be the death of the last individual of that species . Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena. The Silurian The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443.7 ± 1.5 Ma , to the beginning of the Devonian Period, about 416.0 ± 2.8 Ma (ICS, 2004,. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several species Baragwanathia longifolia Baragwanathia is a genus of extinct plants of the division Lycopodiophyta of Late Silurian to Early Devonian age, fossils of which have been found in Australia, Canada and China represents the earliest identifable Lycopodiophyta, while some Cooksonia seem to be related.
Fossils ascribed to the Lycopodiophyta first appear in the Silurian period, along with a number of other vascular plants. Phylogenetic analysis places them at the base of the vascular plants; they are distinguished by their microphylls The terminology of fossil plants is in places a little confusing. In the discipline's 200+ year history, certain concepts have become entrenched, even though improved understanding has threatened the foundations upon which they are based. The traditional definition of microphylls and megaphylls will be employed in this article for simplicity; and by transverse dehiscence of their sporangia (as contrasted with longitudinal in other vascular plants). Sporangia of living species are borne on the upper surfaces of microphylls (called sporophylls A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia (and thus are called megasporophylls), or microsporangia (microsporophylls). The overlap of the prefixes and roots makes these terms a particularly confusing subset of botanical). In some groups, these sporophylls are clustered into strobili A strobilus is a structure present on many plant species consisting of leaf-like, sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but many botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis (anatomically a stem) surrounded.
During the Carboniferous The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Ma , to the beginning of the Permian Period, about 299.0 ± 0.8 Ma (ICS, 2004, period, tree-like Lycopodiophyta (such as Lepidodendron Lepidodendron is an extinct genus of primitive, vascular, arborescent (tree-like) plant related to the Lycopsids (club mosses). It was part of the coal forest flora. They sometimes reached heights of over 30 metres (100 ft), and the trunks were often over 1 m (3.3 ft) in diameter, and thrived during the Carboniferous period. Sometimes called ") formed huge forests and dominated the land. Unlike modern trees, leaves grew out of the entire surface of the trunk and branches, but would fall off as the plant grew, leaving only a small cluster of leaves at the top. Their remains formed many fossil coal Coal is a readily combustible black or brownish-black sedimentary rock normally occurring in rock strata in layers or veins called coal beds. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable deposits. In Fossil Park, Glasgow Glasgow (pronounced /ˈɡlæzɡoʊ/ ; Scots: Glesga Scottish Gaelic: Glaschu) is the largest city in Scotland and third most populous in the United Kingdom. The city is situated on the River Clyde in the country's west central lowlands. A person from Glasgow is known as a Glaswegian, which is also the name of the local dialect, Scotland Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the southwest. In addition to the mainland, Scotland, fossilized Lycopodiophyta trees can be found in sandstone Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, gray and white. Since sandstone beds often form. The trees are marked with diamond-shaped scars where they once had leaves.
Characteristics
Club-mosses are homosporous, but spike-mosses and quillworts are heterosporous, with female spores larger than the male, and gametophytes forming entirely within the spore walls.
The spores of Lycopodiophyta are highly flammable and so have been used in fireworks Fireworks are a class of low explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices. Fireworks competitions are also regularly held at a number of places. Fireworks (devices) take.[7] Currently, huperzine, a chemical isolated from a Chinese clubmoss, is under investigation as a possible treatment for Alzheimer's disease Alzheimer's disease , also called Alzheimer disease, Senile Dementia of the Alzheimer Type (SDAT) or simply Alzheimer's, is the most common form of dementia. This incurable, degenerative, and terminal disease was first described by German psychiatrist and neuropathologist Alois Alzheimer in 1906 and was named after him. Generally, it is diagnosed.
Gallery
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Lycopodites, an early lycopod-like fossil. |
External mold of Lepidodendron from the Upper Carboniferous of Ohio The government of Ohio is composed of the executive branch, led by the Governor; the legislative branch, which comprises the Ohio General Assembly; and the judicial branch, which is led by the Supreme Court. Currently, Ohio occupies 18 seats in the United States House of Representatives. Ohio is known for its status as both a swing state and a. |
Fossil in situ lycopsid, probably Sigillaria, with attached stigmarian roots. |
Base of a fossil lycopsid showing connection with stigmarian roots. |
References
- ^ Cronquist, A.; A. Takhtajan, W. Zimmermann (1966). "On the higher taxa of Embryobionta". Taxon (International Association for Plant Taxonomy (IAPT)) 15 (15): 129–134. doi A digital object identifier is a character string used to uniquely identify an electronic document or other object. Metadata about the object is stored in association with the DOI name and this metadata may include a location, such as a URL, where the object can be found. The DOI for a document is permanent, whereas its location and other metadata:10.2307/1217531. http://jstor.org/stable/1217531.
- ^ Cantino, Philip D.; James A. Doyle, Sean W. Graham, Walter S. Judd, Richard G. Olmstead, Douglas E. Soltis, Pamela S. Soltis, & Michael J. Donoghue (2007). "Towards a phylogenetic nomenclature of Tracheophyta". Taxon 56 (3): E1–E44.
- ^ McElwain, Jenny C.; Willis, K. G.; Willis, Kathy; McElwain, J. C. (2002). The evolution of plants. Oxford [Oxfordshire]: Oxford University Press. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 0-19-850065-3.
- ^ Eichhorn, Evert, and Raven (2005). Biology of Plants, Seventh Edition. 381-388.
- ^ Callow, R. S.; Cook, Laurence Martin (1999). Genetic and evolutionary diversity: the sport of nature. Cheltenham: S. Thornes. ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 0-7487-4336-7.
- ^ "www.ncbi.nlm.nih.gov". http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=3243. Retrieved 2009-03-19.
- ^ Cobb, B (1956) A Field Guide to Ferns and their related families: Northeastern and Central North America with a section on species also found in the British Isles and Western Europe (Peterson Field Guides), 215
External links
| The Wikibook Dichotomous Key has a page on the topic of Lycopodiophyta |
- Introduction to the Lycophyta from the University of California Museum of Paleontology
- Lycophytes
- Fossil Groves
- Paleo Plants
Categories: Living fossils | Lycopodiophyta
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quangtuannhoc
Mon, 27 Apr 2009 14:23:28 GM
L u r ng th c v t co m ch mang bao t la c n nganh i v i th c v t co h t, v i nhom d ng x (Pteridophyta) co quan h h hang g n g i v i th c v t co h t h n la v i thong t (. Lycopodiophyta. ). Th c v t co h t nguyen th y u tien, ...
