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Selaginella Deflexa
''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having spores of two types. They are sometimes included in an informal paraphyletic group called the "fern allies". '' S. moellendorffii'' is an important model organism. Its genome has been sequenced by the United States Department of Energy's Joint Genome Institute. The name ''Selaginella'' was erected by Palisot de Beauvois solely for the species ''Selaginella selaginoides'', which turns out (with the closely related ''Selaginella deflexa'') to be a clade that is sister to all other ''Selaginellas'', so any definitive subdivision of the species into separate genera leaves two taxa in ''Selaginella'', with the hundreds of other species in new or resurrected genera. ''Selaginella'' occurs mostly in the tropical regions of the world, with a hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambroise Marie François Joseph Palisot De Beauvois
Ambroise Marie François Joseph Palisot, Baron de Beauvois (27 July 1752, in Arras – 21 January 1820, in Paris) was a French naturalist and zoologist. Palisot collected insects in Oware, Benin, Saint Domingue, and the United States, from 1786 to 1797. Trained as a botanist, Palisot published a significant entomological paper entitled, "Insectes Receuillis en Afrique et en Amerique". Together with Frederick Valentine Melsheimer, he was one of the first entomologists to collect and describe American insects. He described many common insects and suggested an ordinal classification of insects. He described many Scarabaeidae as well as illustrating them for the first time. The study included 39 '' Scarabaeus'' species, 17 ''Copris'' species, 7 ''Trox'' species, 4 ''Cetonia'' and 4 '' Trichius'' species. Familiar beetles such as '' Canthon viridis'', '' Macrodactylus angustatus'' and '' Osmoderma scabra'' were first described by him. Many of the specimens that were labelled from Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stele (biology)
In a vascular plant, the stele is the central part of the root or stem containing the tissues derived from the procambium. These include vascular tissue, in some cases ground tissue (pith) and a pericycle, which, if present, defines the outermost boundary of the stele. Outside the stele lies the endodermis, which is the innermost cell layer of the cortex. The concept of the stele was developed in the late 19th century by French botanists P. E. L. van Tieghem and H. Doultion as a model for understanding the relationship between the shoot and root, and for discussing the evolution of vascular plant morphology. Now, at the beginning of the 21st century, plant molecular biologists are coming to understand the genetics and developmental pathways that govern tissue patterns in the stele. Moreover, physiologists are examining how the anatomy (sizes and shapes) of different steles affect the function of organs. Protostele The earliest vascular plants had stems with a central core of va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selaginella Plumosa
''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having spores of two types. They are sometimes included in an informal paraphyletic group called the "fern allies". '' S. moellendorffii'' is an important model organism. Its genome has been sequenced by the United States Department of Energy's Joint Genome Institute. The name ''Selaginella'' was erected by Palisot de Beauvois solely for the species ''Selaginella selaginoides'', which turns out (with the closely related ''Selaginella deflexa'') to be a clade that is sister to all other ''Selaginellas'', so any definitive subdivision of the species into separate genera leaves two taxa in ''Selaginella'', with the hundreds of other species in new or resurrected genera. ''Selaginella'' occurs mostly in the tropical regions of the world, with a hand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palisot De Beauvois
Ambroise Marie François Joseph Palisot, Baron de Beauvois (27 July 1752, in Arras – 21 January 1820, in Paris) was a French naturalist and zoologist. Palisot collected insects in Oware, Benin, Saint Domingue, and the United States, from 1786 to 1797. Trained as a botanist, Palisot published a significant entomological paper entitled, "Insectes Receuillis en Afrique et en Amerique". Together with Frederick Valentine Melsheimer, he was one of the first entomologists to collect and describe American insects. He described many common insects and suggested an ordinal classification of insects. He described many Scarabaeidae as well as illustrating them for the first time. The study included 39 '' Scarabaeus'' species, 17 '' Copris'' species, 7 '' Trox'' species, 4 '' Cetonia'' and 4 '' Trichius'' species. Familiar beetles such as '' Canthon viridis'', '' Macrodactylus angustatus'' and '' Osmoderma scabra'' were first described by him. Many of the specimens that were labelled fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopodiopsida
Lycopodiopsida is a class of vascular plants known as lycopods, lycophytes or other terms including the component lyco-. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms formed huge forests that dominated the landscape and contributed to coal deposits. The nomenclature and classification of plants with microphylls varies substantially among authors. A consensus classification for extant (living) species was produced in 2016 by the Pteridophyte Phylogeny Group (PPG I), which places them all in the class Lycopodiopsida, which includes the classes Isoetopsida and Selaginellopsida used in other systems. (See Table 2.) Alternative classification systems have used ranks fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resurrection Plants
A resurrection plant is any poikilohydric plant that can survive extreme dehydration, even over months or years. Examples include: * ''Anastatica hierochuntica'', also known as the Rose of Jericho, a plant species native to deserts of North Africa * ''Asteriscus'' (plant); * '' Boea hygrometrica'', * '' Craterostigma'', members of the Linderniaceae/Scrophulariaceae with snapdragon-like flowers * '' Haberlea rhodopensis'' * ''Lichen'', a symbiosis that can survive in extreme desiccation, * ''Mesembryanthemum'', the plant can revive within a short period of time after a drought * ''Myrothamnus flabellifolius'', a plant species native to Southern Africa * ''Pleopeltis polypodioides'', also known as resurrection fern * ''Ramonda serbica'', a species in the family Gesneriaceae * '' Selaginella lepidophylla'', a plant species native to North America, Central and South America, and sold as a novelty * ''Tillandsia'' * '' Xerophyta'', a monocotyledonous genus typically occurring on rock o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poikilohydry
Poikilohydry is the lack of ability (structural or functional mechanism) to maintain and/or regulate water content to achieve homeostasis In biology, homeostasis (British English, British also homoeostasis) Help:IPA/English, (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physics, physical, and chemistry, chemical conditions maintained by organism, living systems. Thi ... of cells and tissue connected with quick equilibration of cell/tissue water content to that of the environment. The term is derived from Ancient Greek ποικίλος (poikílos, “spotted or variegate”).. Tolerance to desiccation has been utilized in the Archaea, Bacteria, and Eukaryote kingdoms to take advantage of ecological niches. The tolerance to desiccation is often combined with other abiotic stress factors such as temperature extremes, malnutrition, vitamin imbalances, salinity content, and ultraviolet radiation. Many plants control desiccation tolerance through non-specialized structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microphylls And Megaphylls
In plant anatomy and evolution a microphyll (or lycophyll) is a type of plant leaf with one single, unbranched leaf vein. Plants with microphyll leaves occur early in the fossil record, and few such plants exist today. In the classical concept of a microphyll, the leaf vein emerges from the protostele without leaving a leaf gap. Leaf gaps are small areas above the node of some leaves where there is no vascular tissue, as it has all been diverted to the leaf. Megaphylls, in contrast, have multiple veins within the leaf and leaf gaps above them in the stem. Leaf vasculature The clubmosses and horsetails have microphylls, as in all extant species there is only a single vascular trace in each leaf. These leaves are narrow because the width of the blade is limited by the distance water can efficiently diffuse cell-to-cell from the central vascular strand to the margin of the leaf. Despite their name, microphylls are not always small: those of ''Isoëtes'' can reach 25 centimetres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, fungi and protozoa. Bacterial spores are not part of a sexual cycle, but are resistant structures used for survival under unfavourable conditions. Myxozoan spores release amoeboid infectious germs ("amoebulae") into their hosts for parasitic infection, but also reproduce within the hosts through the pairing of two nuclei within the plasmodium, which develops from the amoebula. In plants, spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. Under favourable conditions the spore can develop into a new organism using mitotic division, producing a multicellular gametophyte, which eventually goes on to produce gametes. Two gametes fuse to form a zygote which develops into a new s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligule
A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ray floret in plants in the daisy family Asteraceae. Poaceae and Cyperaceae The ligule is part of the leaf that is found at the junction of the blade and sheath of the leaf. It may take several forms, but it is commonly some form of translucent membrane or a fringe of hairs. The membranous ligule can be very short 1–2 mm (Kentucky bluegrass, ''Poa pratensis'') to very long 10–20 mm (Johnson grass, ''Sorghum halepense''), it can also be smooth on the edge or very ragged. Some grasses do not have a ligule, for example barnyardgrass (''Echinochloa crus-galli''). A ligule can also be defined as a membrane-like tissue or row of delicate hairs typically found in grasses at the junction of the leaf sheath and blade. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Casparian Strips
The Casparian strip is a band-like thickening in the center of the root endodermis (radial and tangential walls of endodermal cells) of vascular plants (Pteridophytes and Spermatophytes). The composition of the region is mainly suberin, lignin and some structural proteins, which are capable of reducing the diffusive apoplastic flow of water and solutes into the Stele (biology), stele and its width varies between species. The Casparian strip is impervious to water so can control the Transpiration stream, transportation of water and inorganic salts between the Cortex (botany), cortex and the vascular bundle, preventing water and inorganic salts from being transported to the Stele (biology), stele through the apoplast, so that it must enter the cell membrane and move to the stele through the symplastic pathway, blocking the internal and external objects of the cell. The function and function of mass transportation are similar to that of animal tissues.. The development of the Casparian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trabeculae
A trabecula (plural trabeculae, from Latin for "small beam") is a small, often microscopic, tissue element in the form of a small beam, strut or rod that supports or anchors a framework of parts within a body or organ. A trabecula generally has a mechanical function, and is usually composed of dense collagenous tissue (such as the trabecula of the spleen). It can be composed of other material such as muscle and bone. In the heart, muscles form trabeculae carneae and septomarginal trabeculae. Cancellous bone is formed from groupings of trabeculated bone tissue. In cross section, trabeculae of a cancellous bone can look like septa, but in three dimensions they are topologically distinct, with trabeculae being roughly rod or pillar-shaped and septa being sheet-like. When crossing fluid-filled spaces, trabeculae may offer the function of resisting tension (as in the penis, see for example trabeculae of corpora cavernosa and trabeculae of corpus spongiosum) or providing a cell fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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