Thallophyte

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Lichens are some of the organisms included in several definitions of the Thallophyte group. CSIRO ScienceImage 4092 Lichen on tree in Adelaide Hills SA 1992.jpg
Lichens are some of the organisms included in several definitions of the Thallophyte group.

Thallophytes (Thallophyta, Thallophyto or Thallobionta) are a polyphyletic group of non-motile organisms traditionally described as "thalloid plants", "relatively simple plants" or "lower plants". They form a division of kingdom Plantae that include lichens and algae and occasionally bryophytes, bacteria and slime moulds. Thallophytes have a hidden reproductive system and hence they are also incorporated into the similar Cryptogamae category (together with ferns), as opposed to Phanerogamae. Thallophytes are defined by having undifferentiated bodies (thalloid, pseudotissue), as opposed to cormophytes (Cormophyta) with roots and stems. Various groups of thallophytes are major contributors to marine ecosystems.

Contents

Definitions

Several different definitions of the group have been used.

Thallophytes (Thallophyta or Thallobionta) are a polyphyletic group of non-mobile organisms traditionally described as "thalloid plants", "relatively simple plants" or "lower plants". Stephan Endlicher, a 19th-century Austrian botanist, separated the vegetable kingdom into the thallophytes (algae, lichens, fungi) and the cormophytes (including bryophytes and thus being equivalent to Embryophyta in this case) in 1836. [1] [2] This definition of Thallophyta is approximately equivalent to Protophyta, which has always been a loosely defined group. [3]

In the Lindley system (1830–1839), Endlicher's cormophytes were divided into the thallogens (including the bryophytes), and cormogens ("non-flowering" plants with roots), as well as the six other classes. Cormogens were a much smaller group than Endlicher's cormophytes, [4] including just the ferns (and Equisetopsida) and the plants now known as lycopodiophytes.

Thallophyta is a division of the plant kingdom including primitive forms of plant life showing a simple plant body. Including unicellular to large algae, fungi, lichens. [5]

The first ten phyla are referred to as thallophytes. They are simple plants without roots stems or leaves. [6]

They are non-embryophyta. These plants grow mainly in water.

Subdivisions

The Thallophyta have been divided into two subdivisions: [7]

The term Euthallophyta was originally used by Adolf Engler. [8]

See also

Related Research Articles

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An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water or from debris accumulating around it. The plants on which epiphytes grow are called phorophytes. Epiphytes take part in nutrient cycles and add to both the diversity and biomass of the ecosystem in which they occur, like any other organism. They are an important source of food for many species. Typically, the older parts of a plant will have more epiphytes growing on them. Epiphytes differ from parasites in that they grow on other plants for physical support and do not necessarily affect the host negatively. An organism that grows on another organism that is not a plant may be called an epibiont. Epiphytes are usually found in the temperate zone or in the tropics. Epiphyte species make good houseplants due to their minimal water and soil requirements. Epiphytes provide a rich and diverse habitat for other organisms including animals, fungi, bacteria, and myxomycetes.

<span class="mw-page-title-main">Lichenology</span> Branch of mycology that studies lichens

Lichenology is the branch of mycology that studies the lichens, symbiotic organisms made up of an intimate symbiotic association of a microscopic alga with a filamentous fungus.

<span class="mw-page-title-main">Lichen</span> Symbiosis of fungi with algae or cyanobacteria

A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Lichens have properties different from those of their component organisms. They come in many colors, sizes, and forms and are sometimes plant-like, but are not plants. They may have tiny, leafless branches (fruticose); flat leaf-like structures (foliose); grow crust-like, adhering tightly to a surface (substrate) like a thick coat of paint (crustose); have a powder-like appearance (leprose); or other growth forms.

<span class="mw-page-title-main">Thallus</span> Undifferentiated vegetative tissue of certain organisms

Thallus, from Latinized Greek θαλλός, meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic group of distantly related organisms. An organism or structure resembling a thallus is called thalloid, thallodal, thalliform, thalline, or thallose.

<span class="mw-page-title-main">Embryophyte</span> Subclade of green plants, also known as land plants

The Embryophyta, or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sister of the Zygnematophyceae. The Embryophyta consist of the bryophytes plus the polysporangiophytes. Living embryophytes therefore include hornworts, liverworts, mosses, lycophytes, ferns, gymnosperms and flowering plants. The land plants have diplobiontic life cycles and it is accepted now that they emerged from freshwater, multi-celled algae.

<span class="mw-page-title-main">Non-vascular plant</span> Plant without a vascular system

Non-vascular plants are plants without a vascular system consisting of xylem and phloem. Instead, they may possess simpler tissues that have specialized functions for the internal transport of water.

<span class="mw-page-title-main">Stephan Endlicher</span> Austrian botanist and linguist

Stephan Ladislaus Endlicher also known as Endlicher István László was an Austrian botanist, numismatist and Sinologist. He was a director of the Botanical Garden of Vienna.

<span class="mw-page-title-main">Epidendroideae</span> Subfamily of orchids

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<span class="mw-page-title-main">Streptophyta</span> Clade consisting of the charophyte algae and land plants

Streptophyta, informally the streptophytes, is a clade of plants. The composition of the clade varies considerably between authors, but the definition employed here includes land plants and all green algae except the Chlorophyta and the more basal Prasinodermophyta.

Rhizoids are protuberances that extend from the lower epidermal cells of bryophytes and algae. They are similar in structure and function to the root hairs of vascular land plants. Similar structures are formed by some fungi. Rhizoids may be unicellular or multicellular.

<span class="mw-page-title-main">Metzgeriales</span> Order of liverwort plants

Metzgeriales is an order of liverworts. The group is sometimes called the simple thalloid liverworts: "thalloid" because the members lack structures resembling stems or leaves, and "simple" because their tissues are thin and relatively undifferentiated. All species in the order have a small gametophyte stage and a smaller, relatively short-lived, spore-bearing stage. Although these plants are almost entirely restricted to regions with high humidity or readily available moisture, the group as a whole is widely distributed, and occurs on every continent except Antarctica.

<span class="mw-page-title-main">Cryptogam</span> Any plant or plant-like organism that reproduces by spores, without flowers or seeds

A cryptogam is a plant or a plant-like organism that reproduces by spores, without flowers or seeds. The name Cryptogamae means "hidden reproduction", referring to the fact that no seed is produced, thus cryptogams represent the non-seed bearing plants. Other names, such as "thallophytes", "lower plants", and "spore plants" are also occasionally used. As a group, Cryptogamae are the opposite of the Phanerogamae or Spermatophyta, the seed plants. The best-known groups of cryptogams are algae, lichens, mosses, and ferns, but it also includes non-photosynthetic organisms traditionally classified as plants, such as fungi, slime molds, and bacteria. The classification is now deprecated in Linnaean taxonomy.

One of the prime systems of plant taxonomy, the Engler system was devised by Adolf Engler (1844–1930), and is featured in two major taxonomic texts he authored or co-authored. His influence is reflected in the use of the terms "Engler School" and "Engler Era". Engler's starting point was that of Eichler who had been the first to use phylogenetic principles, although Engler himself did not think that he was.

The following outline is provided as an overview of and topical guide to botany:

This article attempts to place key plant innovations in a geological context. It concerns itself only with novel adaptations and events that had a major ecological significance, not those that are of solely anthropological interest. The timeline displays a graphical representation of the adaptations; the text attempts to explain the nature and robustness of the evidence.

In biology, a phylum is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature for algae, fungi, and plants accepts the terms as equivalent. Depending on definitions, the animal kingdom Animalia contains about 31 phyla, the plant kingdom Plantae contains about 14 phyla, and the fungus kingdom Fungi contains about 8 phyla. Current research in phylogenetics is uncovering the relationships between phyla, which are contained in larger clades, like Ecdysozoa and Embryophyta.

<span class="mw-page-title-main">Plant</span> Kingdom of mainly multicellular, predominantly photosynthetic eukaryotes

Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae which is sister of the Glaucophyta, and consists of the green algae and Embryophyta. The latter includes the flowering plants, conifers and other gymnosperms, ferns and their allies, hornworts, liverworts, and mosses.

<span class="mw-page-title-main">Cormophyte</span>

Cormophytes (Cormophyta) are the "plants differentiated into roots, shoots and leaves, and well adapted for life on land, comprising pteridophytes and the Spermatophyta." This group of plants include mosses, ferns and seed plants. These plants differ from thallophytes, whose body is referred to as the thallus, i.e. a simple body not differentiated into leaf and stem, as of lichens, multicellular algae and some liverworts.

An early system of plant taxonomy, the Lindley system, was first published by John Lindley as An Introduction to the Natural System of Botany. This was a minor modification of that of de Candolle (1813). He developed this further over a number of publications, including the Nixus plantarum (1833) and a second edition of Natural History (1836), in which he introduced the concept of a higher order of taxonomic rank, the Alliances, in which he embedded the Tribes (families). He also expanded his ideas on Exogens in his entry of that name in the Penny Cyclopedia (1838). In 1839 he revised his division of the plant kingdom into classes in an article in the Botanical Register. Lindley's system culminated in the three editions of his Vegetable Kingdom.

Fungi – "Fungi" is plural for "fungus". A fungus is any member of the group of eukaryotic organisms that includes unicellular microorganisms such as yeasts and molds, as well as multicellular fungi that produce familiar fruiting forms known as mushrooms. Biologists classify these organisms as a kingdom, Fungi, the second highest taxonomic rank of living organism beneath the Eukaryota domain; other kingdoms include plants, animals, protists, and bacteria. One difference that places fungi in a different kingdom is that their cell walls contain chitin, unlike the cell walls of plants, bacteria and some protists. Similar to animals, fungi are heterotrophs, that is, they acquire their food by absorbing dissolved molecules, typically by secreting digestive enzymes into their environment. Growth is their means of mobility, except for spores, which may travel through air or water. Fungi function as the principal decomposers in ecological systems.

References

  1. Stephan Endlicher (1836–1840). "Genera plantarum secundum ordines naturales disposita". F. Beck; The Biodiversity Heritage Library.
  2. Lindley (1846), page 46
  3. Fritsch, F.E. (1929). "Evolutionary Sequence and Affinities among Protophyta". Biological Reviews. 4 (2): 103–151. doi:10.1111/j.1469-185X.1929.tb00884.x. S2CID   85070857.
  4. Lindley (1846), page 49
  5. Abercrombie, M., Hichman, C.J. and Johnson, M.L. 1966. A Dictionary of Biology. Penguin Books.
  6. Robbins, W.W., Weier, T.E. and Stocking, C.R. 1959. Botany an Introduction to Plant Science. Chapman & Hall, Limited, Limited
  7. Awasthi 2010, p. 226.
  8. Rendle 1903.

Bibliography