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Phyllotaxis
In botany, phyllotaxis () or phyllotaxy is the arrangement of leaf, leaves on a plant stem. Phyllotactic spirals form a distinctive class of patterns in nature. Leaf arrangement The basic leaf#Arrangement on the stem, arrangements of leaves on a stem are opposite and alternate (also known as spiral). Leaves may also be Whorl (botany), whorled if several leaves arise, or appear to arise, from the same level (at the same Node (botany), node) on a stem. With an opposite leaf arrangement, two leaves arise from the stem at the same level (at the same Node (botany), node), on opposite sides of the stem. An opposite leaf pair can be thought of as a whorl of two leaves. With an alternate (spiral) pattern, each leaf arises at a different point (node) on the stem. Distichous phyllotaxis, also called "two-ranked leaf arrangement" is a special case of either opposite or alternate leaf arrangement where the leaves on a stem are arranged in two vertical columns on opposite sides of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patterns In Nature
Patterns in nature are visible regularities of form found in the natural world. These patterns recur in different contexts and can sometimes be modelled mathematically. Natural patterns include symmetries, trees, spirals, meanders, waves, foams, tessellations, cracks and stripes. Early Greek philosophers studied pattern, with Plato, Pythagoras and Empedocles attempting to explain order in nature. The modern understanding of visible patterns developed gradually over time. In the 19th century, the Belgian physicist Joseph Plateau examined soap films, leading him to formulate the concept of a minimal surface. The German biologist and artist Ernst Haeckel painted hundreds of marine organisms to emphasise their symmetry. Scottish biologist D'Arcy Thompson pioneered the study of growth patterns in both plants and animals, showing that simple equations could explain spiral growth. In the 20th century, the British mathematician Alan Turing predicted mechanisms of morp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaf
A leaf (: leaves) is a principal appendage of the plant stem, stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, flower, and fruit collectively form the Shoot (botany), shoot system. In most leaves, the primary Photosynthesis, photosynthetic Tissue (biology), tissue is the palisade mesophyll and is located on the upper side of the blade or lamina of the leaf, but in some species, including the mature foliage of ''Eucalyptus'', palisade mesophyll is present on both sides and the leaves are said to be isobilateral. The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper (Glossary of botanical terms#adaxial, adaxial) and lower (Glossary of botanical terms#abaxial, abaxial) surfaces that differ in color, Trichome, hairiness, the number of stomata (pores that intake and output gases), the amount and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gasteria
''Gasteria'' is a genus of succulent plants, native to South Africa and the far south-west corner of Namibia. Naming The genus is named for its stomach-shaped flowers (''"gaster"'' is Greek for "stomach") that result from the swollen base on the corolla. Common names include ''ox-tongue'', ''cow-tongue'', ''lawyer's tongue'' and, occasionally, ''mother-in-law's tongue''. Description Gasterias are recognisable from their thick, hard, succulent "tongue-shaped" leaves. These are either in two opposite ranks (distichous), or in various distinctive spiral arrangements. Their inflorescence is also unique, with their curved, stomach-shaped flowers, which hang from inclined racemes. Distribution The species of this genus are mostly native to the Eastern Cape Province, South Africa, where the bulk of the species occur – especially in the small area between Makhanda and Uniondale which enjoys rainfall throughout the year. However, the distribution of several species extends widely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (botany)
In botany, a whorl or verticil is a whorled arrangement of Leaf, leaves, sepals, petals, stamens, or Gynoecium#Carpels, carpels that radiate from a single point and surround or wrap around the stem or stalk. A leaf whorl consists of at least three elements; a pair of opposite leaves is not called a whorl. For leaves to grow in whorls is fairly rare except in plant species with very short Plant stem, internodes and some other genera (''Galium'', ''Nerium'', ''Elodea'' etc.). Leaf whorls occur in some trees such as ''Brabejum stellatifolium'' and other species in the family Proteaceae (e.g., in the genus ''Banksia''). In plants such as these, crowded internodes within the leaf whorls alternate with long internodes between the whorls. The Morphology (biology), morphology of most flowers (called cyclic flowers) is based on four types of whorls: # The Sepal, calyx: zero or more whorls of sepals at the base # The Petal, corolla: zero or more whorls of petals above the calyx # The Stam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kumara Plicatilis
''Kumara plicatilis'', formerly ''Aloe plicatilis'', the fan-aloe, is a succulent plant endemic to a few mountains in the Fynbos ecoregion, of the Western Cape in South Africa. The plant has an unusual and striking fan-like arrangement of its leaves. It may grow as a large multistemmed shrub or as a small tree. It is one of the two species in the genus '' Kumara''. Name ''Kumara plicatilis'' derives its common name fan-aloe from its former placement in the genus ''Aloe'' and the unusual distichous arrangement of its linear leaves. Its Latin scientific name ''plicatilis'' also means "folded" or "pleated", or possibly "foldable";Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Derivation and Accent; Published by Gerald Duckworth & Co. London, 4th ed 1928 it is in any case a misnomer because the leaves are nothing like plicate and do not fold. In the local Afrikaans language, ''Kumara plicatilis'' is commonly known as the ''waaier aalwyn'' (= 'fan aloe'). It is also c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aloe Polyphylla 1
''Aloe'' (; also written ''Aloë'') is a genus containing over 650 species of flowering succulent plants.WFO (2022): Aloe L. Published on the Internet;http://www.worldfloraonline.org/taxon/wfo-4000001341. Accessed on: 06 Nov 2022 The most widely known species is ''Aloe vera'', or "true aloe". It is called this because it is cultivated as the standard source for assorted pharmaceutical purposes. Other species, such as '' Aloe ferox'', are also cultivated or harvested from the wild for similar applications. The APG IV system (2016) places the genus in the family Asphodelaceae, subfamily Asphodeloideae. Within the subfamily it may be placed in the tribe Aloeae.Stevens, P.F. (2001 onwards).Asphodelaceae. ''Angiosperm Phylogeny Website''. Retrieved 2016-06-09. In the past, it has been assigned to the family Aloaceae (now included in the Asphodeloidae) or to a broadly circumscribed family Liliaceae (the lily family). The plant ''Agave americana'', which is sometimes called "Ame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brabejum Stellatifolium
''Brabejum'' is a genus of a single species of large evergreen tree, ''Brabejum stellatifolium'' in the family Proteaceae, commonly called wild almond, bitter almond or ghoeboontjie. It is restricted in the wild to South Africa's Western Cape province, where it grows in thickets along the banks of streams. The plant is of botanical interest as being Africa's only member of the large grevilleoid subfamily. It is a bushy small tree with branches widely at ground level and numerous erect vigorous stems. Leaves grow up to 6 in (15 cm) long, narrow and bluntly toothed, appear at intervals along the branches, mostly in whorls of 6. In summer, the plant bears white flowers densely crowded on spikes arising from rusty buds at the leaf axils. The fruits to 2 in (5 cm) long, magenta to reddish brown, similar to an almond, appear in autumn. The nut is too bitter to eat; however, in earlier times it was boiled, roasted, and ground to make a "coffee" drink. This tree has special sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crassula Rupestris-PICT3087
''Crassula'' is a genus of succulent plants containing about 200 accepted species, including the popular jade plant (''Crassula ovata''). They are members of the stonecrop family (Crassulaceae) and are native to many parts of the globe, but cultivated varieties originate almost exclusively from species from the Eastern Cape of South Africa. Crassulas are usually propagated by stem or leaf cuttings. Most cultivated forms will tolerate some small degree of frost, but extremes of cold or heat will cause them to lose foliage and die. Taxonomy ''Crassula'' was first formally described by Carl Linnaeus in 1753 with 10 species. Etymology The name crassula comes from the Latin adjective ''crassus'', meaning thick, referring to the thickening of the succulent leaves. Selected species *'' Crassula alata'' *'' Crassula alba'' *'' Crassula alpestris'' (Sand-Coated Crassula) *'' Crassula alstonii'' *'' Crassula aquatica'' (common pigmyweed, water pygmyweed) *'' Crassula arborescens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internode (botany)
A stem is one of two main structural axes of a vascular plant, the other being the root. It supports leaf, leaves, flowers and fruits, transports water and dissolved substances between the roots and the shoots in the xylem and phloem, engages in photosynthesis, stores nutrients, and produces new living tissue. The stem can also be called the culm, halm, haulm, stalk, or thyrsus. The stem is normally divided into nodes and internodes: * The nodes are the points of attachment for leaves and can hold one or more leaves. There are sometimes axillary buds between the stem and leaf which can grow into branches (with leaf, leaves, conifer cones, or inflorescence, flowers). Adventitious roots (e.g. brace roots) may also be produced from the nodes. Vines may produce tendrils from nodes. * The internodes distance one node from another. The term "Shoot (botany), shoots" is often confused with "stems"; "shoots" generally refers to new fresh plant growth, including both stems and other str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macadamia
''Macadamia'' is a genus of four species of trees in the flowering plant family Proteaceae. They are indigenous to Australia—specifically, northeastern New South Wales and central and southeastern Queensland. Two species of the genus are commercially important for their fruit, the macadamia nut (or simply macadamia). Global production in 2015 was . Other names include Queensland nut, bush nut, maroochi nut or bauple nut. It was an important source of Bush tucker, bushfood for the Aboriginal Australians, Aboriginal peoples. The nut was first commercially produced on a wide scale in Hawaii, where Australian seeds were introduced in the 1880s, and which for more than a century was the world's largest producer. South Africa has been the world's largest producer of the macadamia since the 2010s. The macadamia is the only widely grown food plant that is native to Australia. Description ''Macadamia'' is a genus of evergreen trees that grows tall. The leaves are arranged in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
