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APGII
The APG II system (Angiosperm Phylogeny Group II system) of plant classification is the second, now obsolete, version of a modern, mostly molecular-based, system of plant taxonomy that was published in April 2003 by the Angiosperm Phylogeny Group.Angiosperm Phylogeny Group (2003)An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II.''Botanical Journal of the Linnean Society'' 141(4): 399-436. doi: 10.1046/j.1095-8339.2003.t01-1-00158.x It was a revision of the first APG system, published in 1998, and was superseded in 2009 by a further revision, the APG III system. History APG II was published as: *Angiosperm Phylogeny Group (2003). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II". ''Botanical Journal of the Linnean Society'' 141(4): 399-436. (Available onlineAbstractFull text (HTML)Full text (PDF) doi: 10.1046/j.1095-8339.2003.t01-1-00158.x) Each o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunnerales
The Gunnerales are an order of flowering plants. In the APG III system (2009) and APG IV system (2016) it contains two genera: ''Gunnera'' (in family Gunneraceae) and ''Myrothamnus'' (in family Myrothamnaceae). In the Cronquist system (1981), the Gunneraceae were in the Haloragales and Myrothamnaceae in the Hamamelidales. DNA analysis was definitive, but the grouping of the two families was a surprise, given their very dissimilar morphologies. In Cronquist's old system (1981, 1988), and Takhtajan's (1997), the Gunneraceae were in the Rosidae, and the Myrothamnaceae were in the Hamamelids. In modern classification systems such as APG III and APG IV this order was the first to derive from the core eudicots. Description Both families contain ellagic acid. Phloem cells contain a large number of plastids and the leaves have dented borders. The plants are dioecious, have small flowers without perianth, and the stigma is at least weakly secretory. Gunnerales characters shared with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celastrales
The Celastrales are an order of flowering plants found throughout the tropics and subtropics, with only a few species extending far into the temperate regions. The 1200"Lepidobotryaceae", "Parnassiaceae", and "Celastraceae" In: Klaus Kubitzki (ed.). ''The Families and Genera of Vascular Plants'' vol. VI. Springer-Verlag: Berlin;Heidelberg, Germany. (2004). (vol. VI). to 1350Peter F. Stevens (2001 onwards)CelastralesAtaMissouri Botanical Garden/ref> species are in about 100 genera. All but seven of these genera are in the large family Celastraceae. Until recently, the composition of the order and its division into families varied greatly from one author to another. Description The Celastrales are a diverse order that has no conspicuous distinguishing characteristic, so is consequently hard to recognize. The flowers are usually small with a conspicuous nectary disk. The stipules are small or rarely absent. The micropyle has two openings and is therefore called a bistomal micro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monocots
Monocotyledons (), commonly referred to as monocots, ( Lilianae ''sensu'' Chase & Reveal) are grass and grass-like flowering plants (angiosperms), the seeds of which typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided; the rest of the flowering plants have two cotyledons and are classified as dicotyledons, or dicots. Monocotyledons have almost always been recognized as a group, but with various taxonomic ranks and under several different names. The APG III system of 2009 recognises a clade called "monocots" but does not assign it to a taxonomic rank. The monocotyledons include about 60,000 species, about a quarter of all angiosperms. The largest family in this group (and in the flowering plants as a whole) by number of species are the orchids (family Orchidaceae), with more than 20,000 species. About half as many species belong to the true grasses ( Poaceae), which are ec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canellales
Canellales is the botanical name for an order of flowering plants, one of the four orders of the magnoliids. It is recognized by the most recent classification of flowering plants, the APG IV system. It is defined to contain two families: Canellaceae and Winteraceae, which comprise 136 species of fragrant trees and shrubs. The Canellaceae are found in tropical America and Africa, and the Winteraceae are part of the Antarctic flora (found in diverse parts of the southern hemisphere). Although the order was defined based on phylogenetic studies, a number of possible synapomorphies have been suggested, relating to the pollen tube, the seeds, the thickness of the integument, and other aspects of the morphology. Until 1999, these two families were not considered to be closely related. Instead the Winteraceae were considered to be a primitive family (due to the structure of the xylem and carpel, a structure which now seems to be derived from xylem and carpels more typical of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angiosperm Phylogeny Group
The Angiosperm Phylogeny Group (APG) is an informal international group of systematic botanists who collaborate to establish a consensus on the taxonomy of flowering plants (angiosperms) that reflects new knowledge about plant relationships discovered through phylogenetic studies. , four incremental versions of a classification system have resulted from this collaboration, published in 1998, 2003, 2009 and 2016. An important motivation for the group was what they considered deficiencies in prior angiosperm classifications since they were not based on monophyletic groups (i.e., groups that include all the descendants of a common ancestor). APG publications are increasingly influential, with a number of major herbaria changing the arrangement of their collections to match the latest APG system. Angiosperm classification and the APG In the past, classification systems were typically produced by an individual botanist or by a small group. The result was a large number of systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossosomatales
The Crossosomatales are an order, first recognized as such by Angiosperm Phylogeny Group, APG II. They are flowering plants included within the Rosids, Rosid eudicots. Description Species assigned to the Crossosomatales have in common flowers that are positioned solitarily, with the base of the Sepal, calyx, Petal, corolla, and stamens fused into a tube-shaped hypanthium, floral cup, sepals overlapping, the outermost smaller than the inner. Insides of the casings of pollen grains have horizontally extended thin regions (or Pollen#Structure, endo-apertures). The gynoecium is placed on a short stalk, papillae on the stigma consist of two or more cells, Ovary (botany)#Parts of the ovary, ovary locules taper upwards, and the protective cell layer (or Ovule#Integuments, micropyle and chalaza, integument) surrounding the ovule leaves a zigzag opening (or Ovule#Integuments, micropyle and chalaza, micropyle). Some cell clusters have bundles of long yellow crystals, mucilage cells are pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Phylogenetics
Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to determine the processes by which diversity among species has been achieved. The result of a molecular phylogenetic analysis is expressed in a phylogenetic tree. Molecular phylogenetics is one aspect of molecular systematics, a broader term that also includes the use of molecular data in taxonomy and biogeography. Molecular phylogenetics and molecular evolution correlate. Molecular evolution is the process of selective changes (mutations) at a molecular level (genes, proteins, etc.) throughout various branches in the tree of life (evolution). Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree. History The theoretical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Class (biology)
In biological classification, class ( la, classis) is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders. Other well-known ranks in descending order of size are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order. History The class as a distinct rank of biological classification having its own distinctive name (and not just called a ''top-level genus'' ''(genus summum)'') was first introduced by the French botanist Joseph Pitton de Tournefort in his classification of plants that appeared in his ''Eléments de botanique'', 1694. Insofar as a general definition of a class is available, it has historically been conceived as embracing taxa that combine a distinct ''grade'' of organization—i.e. a 'level of complexity', measured in terms of how differentiated their organ systems are into distinct regions or sub-organs—with a distinct ''type'' of construc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnoliids
Magnoliids (or Magnoliidae or Magnolianae) are a clade of flowering plants. With more than 10,000 species, including magnolias, nutmeg, bay laurel, cinnamon, avocado, black pepper, tulip tree and many others, it is the third-largest group of angiosperms after the eudicots and monocots. The group is characterized by trimerous flowers, pollen with one pore, and usually branching-veined leaves. Some members of the subclass are among the earliest angiosperms and share anatomical similarities with gymnosperms like stamens that resemble the male cone scales of conifers and carpels found on the long flowering axis. Classification "Magnoliidae" is the botanical name of a subclass, and "magnoliids" is an informal name that does not conform to the International Code of Nomenclature for algae, fungi, and plants. The circumscription of a subclass will vary with the taxonomic system being used. The only requirement is that it must include the family Magnoliaceae. The informal name "ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commelinids
In plant taxonomy, commelinids (originally commelinoids) (plural, not capitalised) is a clade of flowering plants within the monocots, distinguished by having cell walls containing ferulic acid. The commelinids are the only clade that the APG IV system has informally named within the monocots. The remaining monocots are a paraphyletic unit. Also known as the commelinid monocots it forms one of three groupings within the monocots, and the final branch; the other two groups are the alismatid monocots and the lilioid monocots. Description Members of the commelinid clade have cell walls containing UV-fluorescent ferulic acid. Taxonomy The commelinids were first recognized as a formal group in 1967 by Armen Takhtajan, who named them the Commelinidae and assigned them to a subclass of Liliopsida (monocots). The name was also used in the 1981 Cronquist system. However, by the release of his 1980 system of classification, Takhtajan had merged this subclass into a larger one, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxonomic Rank
In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While older approaches to taxonomic classification were phenomenological, forming groups on the basis of similarities in appearance, organic structure and behaviour, methods based on genetic analysis have opened the road to cladistics. A given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms and groups of organisms related to each other through inheritance of traits or features from common ancestors. The rank of any ''species'' and the description of its ''genus'' is ''basic''; which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two. Consider a particu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eudicots
The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non- magnoliid dicots by previous authors. The botanical terms were introduced in 1991 by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton to emphasize the later evolutionary divergence of tricolpate dicots from earlier, less specialized, dicots. Numerous familiar plants are eudicots, including many common food plants, trees, and ornamentals. Some common and familiar eudicots include sunflower, dandelion, forget-me-not, cabbage, apple, buttercup, maple, and macadamia. Most leafy trees of midlatitudes also belong to eudicots, with notable exceptions being magnolias and tulip trees which belong to magnoliids, and ''Ginkgo biloba'', which is not an angiosperm. Description The close relationships among flowering plants with tricolpa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
