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Hamamelidales
Hamamelidales is an order of flowering plants formerly accepted in a number of systems of plant taxonomy, including the Cronquist system published in 1968 and 1988. The order is not currently accepted in the Angiosperm Phylogeny Group III system of plant taxonomy, the most widely accepted system as molecular systematic studies have suggested that these families are not closely related to each other. The APG II system (2003) assigns them to several different orders: Hamamelidaceae and Cercidiphyllaceae to Saxifragales, Eupteleaceae to Ranunculales, Platanaceae to Proteales, and Myrothamnaceae to Gunnerales. Additional studies of the chloroplast genome have since confirmed that the families moved into the Saxigragales are closely related. The Cronquist system (1981) included the order in subclass Hamamelidae with the circumscription: * order Hamamelidales *: family Hamamelidaceae, now in order Saxifragales *: family Cercidiphyllaceae, now in order Saxifragales *: family Eupteleace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myrothamnus
''Myrothamnus'' is a genus of flowering plants, consisting of two species of small xerophytic shrubs, in the southern parts of tropical Africa and in Madagascar. ''Myrothamnus'' is recognized as the only genus in the family Myrothamnaceae. Myrothamnaceae was included in order Hamamelidales in the Cronquist system. Molecular systematic studies have suggested that ''Myrothamnus'' is not closely related to Hamamelidaceae nor any other family included in that order, but rather is closely related to ''Gunnera''. In the APG II system (2003) the genus is assigned to family Gunneraceae or to the optionally recognized segregate family Myrothamnaceae. In the APG III system (2009) and APG IV system (2016) the narrower circumscription is preferred, and these two families are considered distinct Species Species of ''Myrothamnus'' are dioecious shrubs. # ''Myrothamnus flabellifolius'' Welw. - Angola, Southern Africa, Zimbabwe # ''Myrothamnus moschata ''Myrothamnus moschata'' is a plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saxifragales
The Saxifragales (saxifrages) are an order of flowering plants (Angiosperms). They are an extremely diverse group of plants which include trees, shrubs, perennial herbs, succulent and aquatic plants. The degree of diversity in terms of vegetative and floral features makes it difficult to define common features that unify the order. In the Angiosperm Phylogeny Group classification system, the Saxifragales are placed within the major division of flowering plants referred to as eudicots, specifically the core eudicots. This subgroup consists of the Dilleniaceae, superasterids and superrosids. The superrosids in turn have two components, rosids and Saxifragales. The Saxifragales order has undergone considerable revision since its original classification based purely on plant characteristics. The modern classification is based on genetic studies using molecular phylogenetics. There is an extensive fossil record from the Turonian-Campanian (late Cretaceous) time, about 90 mill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamamelidaceae
Hamamelidaceae, commonly referred to as the witch-hazel family, is a family of flowering plants in the order Saxifragales. The clade consists of shrubs and small trees positioned within the woody clade of the core Saxifragales. An earlier system, the Cronquist system, recognized Hamamelidaceae in the Hamamelidales order. Description The Hamamelidaceae are distinguishable from other families in the Saxifragales due to the range of floral characteristics that are generally uniform though all genera. Uniform characteristics include stipules borne on stems with leaves often 2-ranked. Genera usually have a two carpel gynoecium, although some species show variation. Other characteristics include a multicellular stigma, with shallow papillae or ridges. Anthers Anther structure and the modes of opening are considered to be one of the most important features in the systematics and evolution of hamamelids. The anthers in Hamamelids are on average shorter than in other families in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hamamelidae
Hamamelididae is an obsolete botanical name at the rank of subclass. Because some hamamelidid members bear aments (''i.e.'', catkins), this subclass has been formerly known as ''Amentiferae''. Based on molecular phylogeny works, Hamamelididae appears to be a polyphyletic group.Savolainen, V., M. W. Chase, S. B. Hoot, C. M. Morton, D. E. Soltis, C. Bayer, M. F. Fay, A. Y. De Bruijn, S. Sullivan, and Y.-L. Qiu. 2000. Phylogenetics of flowering plants based on combined analysis of plastid ''atpB'' and ''rbcL'' gene sequences. ''Systematic Biology'' 49:306-362. Soltis, D. E. et alii. (28 authors). 2011. "Angiosperm phylogeny: 17 genes, 640 taxa". ''American Journal of Botany'' 98(4):704-730. A well-known system that used the name Hamamelididae is the Cronquist system, although in the disallowed spelling ''Hamamelidae''. In the original 1981 version of this system the circumscription was: * subclass Hamamelidae *: order Trochodendrales *: order Hamamelidales *: order Daphniphyll ... [...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] |
Cronquist System
The Cronquist system is a taxonomic classification system of flowering plants. It was developed by Arthur Cronquist in a series of monographs and texts, including ''The Evolution and Classification of Flowering Plants'' (1968; 2nd edition, 1988) and ''An Integrated System of Classification of Flowering Plants'' (1981) (''see'' Bibliography). Cronquist's system places flowering plants into two broad classes, Magnoliopsida ( dicotyledons) and Liliopsida (monocotyledons). Within these classes, related orders are grouped into subclasses. While the scheme was widely used, in either the original form or in adapted versions, many botanists now use the Angiosperm Phylogeny Group classification for the orders and families of flowering plants, first developed in 1998. The system as laid out in Cronquist's ''An Integrated System of Classification of Flowering Plants'' (1981) counts 64 orders and 321 families in class Magnoliopsida and 19 orders and 65 families in class Liliopsida. ''The Evo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
APG II System
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] |
APG III System
The APG III system of flowering plant classification is the third version of a modern, mostly molecular-based, system of plant taxonomy being developed by the Angiosperm Phylogeny Group (APG). Published in 2009, it was superseded in 2016 by a further revision, the APG IV system. Along with the publication outlining the new system, there were two accompanying publications in the same issue of the Botanical Journal of the Linnean Society: * The first, by Chase & Reveal, was a formal phylogenetic classification of all land plants (embryophytes), compatible with the APG III classification. As the APG have chosen to eschew ranks above order, this paper was meant to fit the system into the existing Linnaean hierarchy for those that prefer such a classification. The result was that all land plants were placed in the class Equisetopsida, which was then divided into 16 subclasses and a multitude of superorders. * The second, by Haston ''et al.'', was a linear sequence of families followi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ranunculales
Ranunculales is an order of flowering plants. Of necessity it contains the family Ranunculaceae, the buttercup family, because the name of the order is based on the name of a genus in that family. Ranunculales belongs to a paraphyletic group known as the basal eudicots. It is the most basal clade in this group; in other words, it is sister to the remaining eudicots. Widely known members include poppies, barberries, hellebores, and buttercups. Taxonomy The Angiosperm Phylogeny Group recognized seven families in Ranunculales in their APG III system, published in 2009. In the preceding APG II system, they offered the option of three segregate families as shown below. * order Ranunculales *: family Berberidaceae *: family Circaeasteraceae *:: family Kingdoniaceae ">Kingdoniaceae.html" ;"title=" family Kingdoniaceae"> family Kingdoniaceae *: family Eupteleaceae *: family Lardizabalaceae *: family Menispermaceae *: family Papaveraceae *:: [+ family Fumariaceae ] *:: [+ family Pte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proteales
Proteales is an order of flowering plants consisting of three (or four) families. The Proteales have been recognized by almost all taxonomists. The representatives of the Proteales are very different from each other. The order contains plants that do not look alike at all. What they have in common is seeds with little or no endosperm. The ovules are often atropic. Families In the classification system of Dahlgren the Proteales were in the superorder Proteiflorae (also called Proteanae). The APG II system of 2003 also recognizes this order, and places it in the clade eudicots with this circumscription: * order Proteales :* family Nelumbonaceae :* family Proteaceae family Platanaceae">Platanaceae.html" ;"title=" family Platanaceae"> family Platanaceae with "+ ..." = optionally separate family (that may be split off from the preceding family). The APG III system of 2009 followed this same approach, but favored the narrower circumscription of the three families, firmly recog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering Plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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