? Plants
Fern Leaf
Scientific classification
Domain: Eukaryota Kingdom: Plantae Haeckel Subkingdom: Embryophyta
Divisions
Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - "true" ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants

The embryophytes are the most familiar group of plants, including trees, flowers, ferns, mosses, and various others. All are complex multicellular organisms with specialized reproductive organs and, with very few exceptions, they obtain their energy through photosynthesis, i.e. by absorbing light, and synthesize food from carbon dioxide. They may be distinguished from multicellular algae by having sterile tissue within the reproductive organs. Further, embryophytes are primarily adapted for life on land, although some are secondarily aquatic. Accordingly they are often called land plants. Image File history File links Download high resolution version (1600x880, 248 KB) Ferns (Blechnum nudum) in Nunniong, Australia File links The following pages link to this file: Plant Fern Embryophyte Wikipedia talk:WikiProject Tree of Life User talk:Tannin User:Fir0002/Fir0002 gallery Wikipedia:Reference desk archive/July 2005 ... Jump to: navigation, search Scientific classification or biological classification is how biologists group and categorize extinct and living species of organisms. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Divisions Green algae land plants (embryophytes) non-vascular embryophytes Hepatophyta - liverworts Anthocerophyta - hornworts Bryophyta - mosses vascular plants (tracheophytes) seedless vascular plants Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongue ferns seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering... Ernst Haeckel Ernst Heinrich Philipp August Haeckel (February 16, 1834 - August 8, 1919), also written von Haeckel, was a German biologist and philosopher who popularized Charles Darwins work in Germany. ... Jump to: navigation, search Bryophytes are embryophyte plants (land plants) that are nevertheless non-vascular: they have tissues and enclosed reproductive systems, but they lack vascular tissue that circulates liquids. ... Orders Haplomitriales Sphaerocarpales Marchantiales Metzgeriales Monocleales Jungermanniales Takakiales Liverworts are non-vascular plants, also called hepatics (scientific name Hepaticophyta). ... Hornworts (or horned liverworts) are a group of non-vascular plants comprising the class Anthocerotae. ... Jump to: navigation, search Subclasses Andreaeidae Sphagnidae Tetraphidae Polytrichidae Buxbaumiidae Bryidae Archidiidae Moss on a rock Mosses belong to the non-vascular plants. ... Jump to: navigation, search Divisions Non-seed-bearing plants Equisetophyta Lycopodiophyta Psilotophyta Pteridophyta Superdivision Spermatophyta Pinophyta Cycadophyta Ginkgophyta Gnetophyta Magnoliophyta The vascular plants are a plant group including the ferns, clubmosses, horsetails, flowering plants, conifers and other gymnosperms. ... Classes Lycopodiopsida - clubmosses Selaginellopsida - spikemosses Isoetopsida - quillworts The division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae that includes some of the most primitive of extant (living) vascular plants. ... Classes Equisetopsida The division Equisetophyta is a taxon in the kingdom Plantae containing primitive land plants. ... Jump to: navigation, search Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... Species Psilotum nudum (L.) Beauvois - Whisk Fern Psilotum complanatum Sw. ... Families and Genera Family Ophioglossaceae Ophioglossum Cheiroglossa Family Botrychiaceae Botrychium Botrypus Sceptridium Family Helminthostachiaceae Helminthostachys zeylanica The Ophioglossophyta are a small group of plants. ... The spermatophytes comprise those plants that produce seeds. ... Pteridospermatophyta, also called seed ferns, is an extinct gymnosperm division of the Plantae kingdom. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... Families Cycadaceae cycas family Stangeriaceae stangeria family Zamiaceae zamia family Cycads are an ancient group of seed plants characterized by a large crown of compound leaves and a stout trunk. ... Jump to: navigation, search Binomial name Ginkgo biloba L. The Ginkgo (Ginkgo biloba), sometimes also known as the Maidenhair Tree, is a unique tree with no close living relatives. ... taxa: Gnetales Welwitschiales Ephedrales The plant division Gnetophyta or gnetophytes comprise three related families of woody plants grouped in the gymnosperms, a paraphyletic group of seed plant divisions. ... Jump to: navigation, search Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms) are a major group of land plants. ... Jump to: navigation, search Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants... Jump to: navigation, search Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... Jump to: navigation, search Subclasses Andreaeidae Sphagnidae Tetraphidae Polytrichidae Buxbaumiidae Bryidae Archidiidae Moss on a rock Mosses belong to the non-vascular plants. ... Multicellular organisms are those organisms containing more than one cell, and having differentiated cells that perform specialized functions. ... Jump to: navigation, search Leaf. ... Jump to: navigation, search Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ...

Embryophytes developed from complex green algae during the Palaeozoic era. Their closest living relatives are the Charales or stoneworts. These algae undergo an alternation between haploid and diploid generations, respectively called gametophytes and sporophytes. In the first embryophytes, however, the sporophytes became very different in structure and function, remaining small and dependent on the parent for their entire brief life. Such plants are called bryophytes; they include three surviving groups: Divisions Chlorophyta Charophyta Streptophytina (Subdivision) The green algae are the large group of algae from which the embryophytes (higher plants) emerged. ... The Palaeozoic is a major division of the geologic timescale, one of four geologic eras. ... Jump to: navigation, search Genera Chara Lamprothamnium Nitella Tolypella The Charales are an order of green algae, and are believed to be the closest relatives of the embryophyte plants. ... Jump to: navigation, search Sporic or diplohaplontic life cycle. ... Haploid (meaning simple in Greek) cells have only one copy of each chromosome. ... Diploid (meaning double in Greek) cells have two copies (homologs) of each chromosome (both sex- and non-sex determining chromosomes), usually one from the mother and one from the father. ... A gametophyte is the haploid structure or phase of life of a sexually reproducing plant. ... A sporophyte is the diploid structure or phase of life of a sexually reproducing plant. ... Bryophyte is a botanical term which refers to any member of the following divisions of the Plantae kingdom: Bryophyta (mosses) Anthocerophyta (hornworts) Hepatophyta (liverworts) Despite the similarity in name, a bryophyte does not exclusively imply a species of the division bryophyta. ...

• Bryophyta (mosses)
• Anthocerotophyta (hornworts)
• Marchantiophyta (liverworts)

All bryophytes are relatively small and are usually confined to moist environments, relying on water to disperse their spores. Other plants better adapted to terrestrial conditions appeared during the Silurian, and during the Devonian they diversified and spread to many different land environments. These are called vascular plants or tracheophytes. They have vascular tissues or tracheids, which transport water throughout the body, and an outer layer or cuticle that resists desiccation. In most the sporophyte is the dominant individual, and develops true leaves, stems, and roots, while the gametophyte remains very small. Jump to: navigation, search Subclasses Andreaeidae Sphagnidae Tetraphidae Polytrichidae Buxbaumiidae Bryidae Archidiidae Moss on a rock Mosses belong to the non-vascular plants. ... Hornworts (or horned liverworts) are a group of non-vascular plants comprising the class Anthocerotae. ... Orders Haplomitriales Sphaerocarpales Marchantiales Metzgeriales Monocleales Jungermanniales Takakiales Liverworts are non-vascular plants, also called hepatics (scientific name Hepaticophyta). ... The term spore have several different meanings in biology. ... Jump to: navigation, search The Silurian is a major division of the geologic timescale that extends from the end of the Ordovician period, about 443. ... Jump to: navigation, search Disambiguation: Devonian is also an adjective relating to the English county of Devon or the people there. ... Jump to: navigation, search Divisions Non-seed-bearing plants Equisetophyta Lycopodiophyta Psilotophyta Pteridophyta Superdivision Spermatophyta Pinophyta Cycadophyta Ginkgophyta Gnetophyta Magnoliophyta The vascular plants are a plant group including the ferns, clubmosses, horsetails, flowering plants, conifers and other gymnosperms. ... Tracheids are long tubular cells in the wooden parts of plants. ... Jump to: navigation, search In botany, a leaf is an above-ground plant organ specialized for photosynthesis. ... In common parlance, a stem is any elongated, usually narrow, extension or supporting structure of an object. ... a cow In vascular plants, the root is that organ of a plant body that typically lies below the surface of the soil (compare with stem). ...

Many vascular plants still reproduce using spores, including the following extant groups:

• Lycopodiophyta (clubmosses)
• Equisetophyta (horsetails)
• Psilotophyta (whisk ferns)
• Ophioglossophyta (adders-tongues and grape-ferns)
• Pteridophyta (ferns)

Other groups, which first appeared towards the end of the Palaeozoic, reproduce using desiccation-resistant capsules called seeds. They are accordingly are called spermatophytes or seed plants. In these forms the gametophyte is completely reduced, taking the form of single-celled pollen and ova, and the sporophyte begins its life enclosed within the seed. Some seed plants may survive in extremely arid conditions. They include the following extant groups: Classes Lycopodiopsida - clubmosses Selaginellopsida - spikemosses Isoetopsida - quillworts The division Lycopodiophyta is a tracheophyte subdivision of the Kingdom Plantae that includes some of the most primitive of extant (living) vascular plants. ... Families Lycopodiaceae Huperziaceae The Class Lycopodiopsida includes the clubmosses. ... Classes Equisetopsida The division Equisetophyta is a taxon in the kingdom Plantae containing primitive land plants. ... Species Subgenus Equisetum Equisetum arvense - Field or Common Horsetail Equisetum bogotense - Andean Horsetail Equisetum diffusum - Himalayan Horsetail Equisetum fluviatile - Water Horsetail Equisetum palustre - Marsh Horsetail Equisetum pratense - Shade Horsetail Equisetum sylvaticum - Wood Horsetail Equisetum telmateia - Great Horsetail Subgenus Hippochaete Equisetum giganteum - Giant Horsetail Equisetum myriochaetum - Mexican Giant Horsetail Equisetum hyemale... Species Psilotum nudum (L.) Beauvois - Whisk Fern Psilotum complanatum Sw. ... Species Psilotum nudum (L.) Beauvois - Whisk Fern Psilotum complanatum Sw. ... Families and Genera Family Ophioglossaceae Ophioglossum Cheiroglossa Family Botrychiaceae Botrychium Botrypus Sceptridium Family Helminthostachiaceae Helminthostachys zeylanica The Ophioglossophyta are a small group of plants. ... Species Ophioglossum azoricum Ophioglossum engelmanii Ophioglossum lusitanicum Ophioglossum pycnosticum Ophioglossum vulgatum Adders-tongues are plants of the genus Ophioglossum, which means snake-tongue. Ophioglossum is in the family Ophioglossaceae, in the order Ophioglossales, a small group of vascular plants. ... Species Botrypus virginianum Grape-ferns are seedless vascular plants of the genus Botrypus, closely allied to (and previously often included in) the genus Botrychium (moonworts). ... Classes Marattiopsida Osmundopsida Gleicheniopsida Pteridopsida A fern, or pteridophyte, is any one of a group of some twenty thousand species of plants classified in the Division Pteridophyta, formerly known as Filicophyta. ... Jump to: navigation, search A seed is the ripened ovule of gymnosperm or angiosperm plants. ... The spermatophytes (also known as phanerogams) comprise those plants that produce seeds. ... Jump to: navigation, search SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomea purpurea), hollyhock (Sildalcea malviflora), lily (Lilium auratum), primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... A human ovum An ovum (loosely, egg or egg cell) is a female sex cell or gamete. ...

• Cycadophyta (Cycads)
• Ginkgophyta (Ginkgo)
• Pinophyta (Conifers)
• Gnetophyta (Gnetae)
• Magnoliophyta (Flowering plants)

The first four groups are referred to as gymnosperms, since the embryonic sporophyte is not enclosed until after pollination. In contrast, the flowering plants or angiosperms the pollen has to grow a tube to penetrate the seed coat. They were the last major group of plants to appear, developing from gymnosperms during the Jurassic and spreading rapidly during the Cretaceous. They are the predominant group of plants in most terrestrial biomes today. Families Cycadaceae cycas family Stangeriaceae stangeria family Zamiaceae zamia family Cycads are an ancient group of seed plants characterized by a large crown of compound leaves and a stout trunk. ... Jump to: navigation, search Binomial name Ginkgo biloba L. The Ginkgo (Ginkgo biloba), sometimes also known as the Maidenhair Tree, is a unique tree with no close living relatives. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... taxa: Gnetales Welwitschiales Ephedrales The plant division Gnetophyta or gnetophytes comprise three related families of woody plants grouped in the gymnosperms, a paraphyletic group of seed plant divisions. ... Jump to: navigation, search Classes Magnoliopsida - Dicots Liliopsida - Monocots The flowering plants (also angiosperms) are a major group of land plants. ... Jump to: navigation, search The Jurassic period is a major unit of the geologic timescale that extends from about 200 Ma (million years ago) at the end of the Triassic to 146 Ma at the beginning of the Cretaceous. ... The Cretaceous period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic period (about 146 MYA) to the beginning of the Paleocene epoch of the Tertiary period (65. ...

Note the higher-level classification of plants varies considerably. Some authors have restricted the kingdom Plantae to include only embryophytes, others have given them various names and ranks. The groups listed here are often considered divisions or phyla, but have also been treated as classes, and they are occasionally compressed into as few as two divisions.

On a microscopic level, embryophyte cells remain very similar to those of green algae. They are eukaryotic, with a cell wall composed of cellulose and plastids surrounded by two membranes. These usually take the form of chloroplasts, which conduct photosynthesis and store food in the form of starch, and characteristically are pigmented with chlorophylls a and b, generally giving them a bright green color. Embryophytes also generally have an enlarged central vacuole or tonoplast, which maintains cell turgor and keeps the plant rigid. They lack flagella and centrioles except in certain gametes. Jump to: navigation, search Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Jump to: navigation, search A cell wall is a more or less solid layer surrounding a cell. ... Cellulose (C6H10O5)n is a long-chain polymer polysaccharide carbohydrate, of beta-glucose. ... Jump to: navigation, search Plastids are major organelles found only in plants and algae. ... Jump to: navigation, search The inside of a chloroplast Chloroplasts are organelles found in plant cells and eukaryotic algae which conduct photosynthesis. ... Jump to: navigation, search Starch is a complex carbohydrate which is insoluble in water. ... Jump to: navigation, search Chlorophyll is a green photosynthetic pigment found in plants, algae, and cyanobacteria. ... Jump to: navigation, search Vacuoles are large membrane-bound compartments within some eukaryotic cells where they serve a variety of different functions: capturing food materials or unwanted structural debris surrounding the cell, sequestering materials that might be toxic to the cell, maintaining fluid balance (called turgor) within the cell, exporting... Turgor (also called turgor pressure or osmotic pressure) is the pressure that can build in a space that is enclosed by a membrane that is permeable to a solvent of a solution such as water but not to the solutes of the soluton. ... Jump to: navigation, search A flagellum (plural, flagella) is a whip-like organelle that many unicellular organisms, and some multicellular ones, use to move about. ... Jump to: navigation, search The centriole is the smallest part of a cell. ... Gametes (in Greek: γαμέτες) —also known as sex cells, or spores—are the specialized germ cells that come together during fertilization (conception) in organisms that reproduce sexually. ...

References

• Kenrick, Paul & Crane, Peter R. (1997). The Origin and Early Diversification of Land Plants: A Cladistic Study. Washington, D. C.: Smithsonian Institution Press. ISBN 1-56098-730-8.
• Raven, Peter H., Evert, Ray F., & Eichhorn, Susan E. (2005). Biology of Plants (7th ed.). New York: W. H. Freeman and Company. ISBN 0-7167-1007-2.
• Stewart, Wilson N. & Rothwell, Gar W. (1993). Paleobotany and the Evolution of Plants (2nd ed.). Cambridge: Cambridge University Press. ISBN 0-521-38294-7.
• Taylor, Thomas N. & Taylor, Edith L. (1993). The Biology and Evolution of Fossil Plants. Englewood Cliffs, NJ: Prentice Hall. ISBN 0-13-651589-4.