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83-401: Cyperus papyrus , better known by the common names papyrus , papyrus sedge , paper reed , Indian matting plant , or Nile grass , is a species of aquatic flowering plant belonging to the sedge family Cyperaceae . It is a tender herbaceous perennial , native to Africa, and forms tall stands of reed-like swamp vegetation in shallow water. Papyrus sedge (and its close relatives) has

166-463: A "frame" at the original level around the edge of the relief, or place a head in a hemispherical recess in the block (see Roman example in gallery). Though essentially very similar to Egyptian sunk relief, but with a background space at the lower level around the figure, the term would not normally be used of such works. It is also used for carving letters (typically om mani padme hum ) in the mani stones of Tibetan Buddhism . Sunk relief technique

249-730: A comprehensive overview of alien aquatic plants in 46 European countries found 96 alien aquatic species. The aliens were primarily native to North America, Asia, and South America. The most spread alien plant in Europe was Elodea canadensis (Found in 41 European countries) followed by Azolla filiculoides in 25 countries and Vallisneria spiralis in 22 countries. The countries with the most recorded alien aquatic plant species were France and Italy with 30 species followed by Germany with 27 species, and Belgium and Hungary with 26 species. The European and Mediterranean Plant Protection Organization has published recommendations to European nations advocating

332-662: A drill rather than chisels , enabling and encouraging compositions extremely crowded with figures, like the Ludovisi Battle sarcophagus (250–260 CE). These are also seen in the enormous strips of reliefs that wound around Roman triumphal columns . The sarcophagi in particular exerted a huge influence on later Western sculpture. The European Middle Ages tended to use high relief for all purposes in stone, though like Ancient Roman sculpture , their reliefs were typically not as high as in Ancient Greece. Very high relief re-emerged in

415-631: A few larger caskets like the Casket with Scenes of Romances (Walters 71264) in Baltimore , Maryland , in the United States. Originally they were very often painted in bright colours. Reliefs can be impressed by stamps onto clay, or the clay pressed into a mould bearing the design, as was usual with the mass-produced terra sigillata of Ancient Roman pottery . Decorative reliefs in plaster or stucco may be much larger; this form of architectural decoration

498-417: A food source. Examples include wild rice ( Zizania ), water caltrop ( Trapa natans ), Chinese water chestnut ( Eleocharis dulcis ), Indian lotus ( Nelumbo nucifera ), water spinach ( Ipomoea aquatica ), prickly waterlily ( Euryale ferox ), and watercress ( Rorippa nasturtium-aquaticum ). A decline in a macrophyte community may indicate water quality problems and changes in the ecological status of

581-543: A gem seal, perhaps as sculptors trained in the Greek tradition attempted to use traditional Egyptian conventions. Small-scale reliefs have been carved in various materials, notably ivory , wood, and wax. Reliefs are often found in decorative arts such as ceramics and metalwork ; these are less often described as "reliefs" than as "in relief". Small bronze reliefs are often in the form of "plaques" or plaquettes , which may be set in furniture or framed, or just kept as they are,

664-503: A lack of pressure that terrestrial plants experience. Green algae are also known to have extremely thin cell walls due to their aquatic surroundings, and research has shown that green algae is the closest ancestor to living terrestrial and aquatic plants. Terrestrial plants have rigid cell walls meant for withstanding harsh weather, as well as keeping the plant upright as the plant resists gravity. Gravitropism, along with phototropism and hydrotropism, are traits believed to have evolved during

747-625: A large proportion of the survivals of portable secular art from Late Antiquity . In the Gothic period the carving of ivory reliefs became a considerable luxury industry in Paris and other centres. As well as small diptychs and triptychs with densely packed religious scenes, usually from the New Testament , secular objects, usually in a lower relief, were also produced. These were often round mirror-cases, combs, handles, and other small items, but included

830-486: A popular form for European collectors, especially in the Renaissance. Various modelling techniques are used, such repoussé ("pushed-back") in metalwork, where a thin metal plate is shaped from behind using various metal or wood punches, producing a relief image. Casting has also been widely used in bronze and other metals. Casting and repoussé are often used in concert in to speed up production and add greater detail to

913-517: A revival in the 20th century, being popular on buildings in Art Deco and related styles, which borrowed from the ancient low reliefs now available in museums. Some sculptors, including Eric Gill , have adopted the "squashed" depth of low relief in works that are actually free-standing. Mid-relief, "half-relief" or mezzo-rilievo is somewhat imprecisely defined, and the term is not often used in English,

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996-413: A sculpture in the round, especially one of a standing figure where the ankles are a potential weak point, particularly in stone. In other materials such as metal, clay, plaster stucco , ceramics or papier-mâché the form can be simply added to or raised up from the background. Monumental bronze reliefs are made by casting . There are different degrees of relief depending on the degree of projection of

1079-456: A side in width. It forms a grass-like clump of triangular green stems that rise up from thick, woody rhizomes . Each stem is topped by a dense cluster of thin, bright green, thread-like rays around 10 to 30 cm (4 to 10 in) in length, resembling a feather duster when the plant is young. Greenish-brown flower clusters eventually appear at the ends of the rays, giving way to brown, nut-like fruits . Although no leaves are apparent above

1162-453: A single figure; accordingly some writers prefer to avoid all distinctions. The opposite of relief sculpture is counter-relief , intaglio , or cavo-rilievo , where the form is cut into the field or background rather than rising from it; this is very rare in monumental sculpture . Hyphens may or may not be used in all these terms, though they are rarely seen in "sunk relief" and are usual in " bas-relief " and "counter-relief". Works in

1245-464: A very long history of use by humans, notably by the Ancient Egyptians (as it is the source of papyrus paper, one of the first types of paper ever made). Parts of the plant can be eaten, and the highly buoyant stems can be made into boats. It is now often cultivated as an ornamental plant . In nature, it grows in full sun, in flooded swamps, and on lake margins throughout Africa, Madagascar, and

1328-504: Is by wind, not insects, and the mature fruits after release are distributed by water. Papyrus is a C4 sedge that forms highly productive monotypic stands over large areas of wetland in Africa. The papyrus plant is relatively easy to grow from seed, though in Egypt, it is more common to split the rootstock , and grows quite fast once established. Extremely moist soil or roots sunken in the water

1411-410: Is complete, the plant descends through the water column and the roots atrophy. In floating aquatic angiosperms, the leaves have evolved to only have stomata on the top surface to make use of atmospheric carbon dioxide. Gas exchange primarily occurs through the top surface of the leaf due to the position of the stomata, and the stomata are in a permanently open state. Due to their aquatic surroundings,

1494-520: Is found in many styles of interiors in the post-Renaissance West, and in Islamic architecture . Many modern and contemporary artists such as Paul Gauguin , Ernst Barlach , Ernst Ludwig Kirchner , Pablo Picasso , Eric Gill , Jacob Epstein , Henry Moore , Claudia Cobizev , up to Ewald Matare have created reliefs. In particular low reliefs were often used in the 20th century on the outsides of buildings, where they are relatively easy to incorporate into

1577-653: Is frequently saturated , and are therefore a common component of swamps and marshlands . One of the largest aquatic plants in the world is the Bolivian waterlily , which holds the Guinness World Record of having the largest undivided leaf at 3.2 m (10 ft 6 in) diameter; the smallest is the rootless duckweed , which is only 1 mm (0.039 in) across. Many small animals use aquatic plants such as duckweeds and lily pads for spawning or as protective shelters against predators both from above and below

1660-423: Is not to be confused with "counter-relief" or intaglio as seen on engraved gem seals – where an image is fully modeled in a "negative" manner. The image goes into the surface, so that when impressed on wax it gives an impression in normal relief. However many engraved gems were carved in cameo or normal relief. A few very late Hellenistic monumental carvings in Egypt use full "negative" modelling as though on

1743-478: Is often used for the background areas of compositions with the main elements in low-relief, but its use over a whole (usually rather small) piece was effectively invented and perfected by the Italian Renaissance sculptor Donatello . In later Western art, until a 20th-century revival, low relief was used mostly for smaller works or combined with higher relief to convey a sense of distance, or to give depth to

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1826-616: Is preferred and the plant can flower all year long. Vegetative propagation is the suggested process of creating new plants. It is done by splitting the rhizomes into small groups and planting normally. It can reach heights of up to 16 feet tall. C. papyrus is considered to be hardy in USDA hardiness zones 9 and 10. C. papyrus and the dwarf cultivar C. papyrus 'Nanus' have gained the Royal Horticultural Society 's Award of Garden Merit (confirmed 2017). In Ancient Egypt, papyrus

1909-482: Is supported by the evidence that several of the earliest known fossil angiosperms were aquatic. Aquatic plants are phylogenetically well dispersed across the angiosperms , with at least 50 independent origins, although they comprise less than 2% of the angiosperm species. Archaefructus represents one of the oldest, most complete angiosperm fossils which is around 125 million years old. These plants require special adaptations for living submerged in water or floating at

1992-424: Is therefore cheaper to produce, as less of the background needs to be removed in a carving, or less modelling is required. In the art of Ancient Egypt , Assyrian palace reliefs , and other ancient Near Eastern and Asian cultures, a consistent very low relief was commonly used for the whole composition. These images would usually be painted after carving, which helped define the forms; today the paint has worn off in

2075-510: The Alhambra ), Rome, and Europe from at least the Renaissance, as well as probably elsewhere. However, it needs very good conditions to survive long in unmaintained buildings – Roman decorative plasterwork is mainly known from Pompeii and other sites buried by ash from Mount Vesuvius . Low relief was relatively rare in Western medieval art , but may be found, for example in wooden figures or scenes on

2158-474: The Khmer Empire . High relief (or altorilievo , from Italian ) is where in general more than half the mass of the sculpted figure projects from the background. Indeed, the most prominent elements of the composition, especially heads and limbs, are often completely undercut, detaching them from the field. The parts of the subject that are seen are normally depicted at their full depth, unlike low relief where

2241-743: The Okavango Delta use small sections of the stem as floats for their nets. Papyrus can be found in tropical rain forests, tolerating annual temperatures of 20 to 30 °C (68 to 86 °F) and a soil pH of 6.0 to 8.5. It flowers in late summer, and prefers full sun to partly shady conditions. Like most tropical plants, it is sensitive to frost. In the United States, it has become invasive in Florida and has escaped from cultivation in Louisiana , California , and Hawaii . Papyrus sedge forms vast stands in swamps, shallow lakes, and along stream banks throughout

2324-994: The 1,460 panels of the 9th-century Borobudur temple in Central Java , Indonesia , narrating the Jataka tales or lives of the Buddha . Other examples are low reliefs narrating the Ramayana Hindu epic in Prambanan temple, also in Java, in Cambodia , the temples of Angkor , with scenes including the Samudra manthan or "Churning the Ocean of Milk" at the 12th-century Angkor Wat , and reliefs of apsaras . At Bayon temple in Angkor Thom there are scenes of daily life in

2407-581: The 16th century it was used for large figures (many also using high relief) at the Chateau of Fontainebleau , which were imitated more crudely elsewhere, for example in the Elizabethan Hardwick Hall . Shallow-relief, in Italian rilievo stiacciato or rilievo schicciato ("squashed relief"), is a very shallow relief, which merges into engraving in places, and can be hard to read in photographs. It

2490-658: The Mediterranean countries. It has been introduced outside its range to tropical regions worldwide (such as the Indian subcontinent, South America, and the Caribbean). This tall, robust aquatic plant can grow 4 to 5 m (13 to 16 ft) high, but on the margins of high altitude lakes such as Lake Naivasha in Kenya and Lake Tana in Ethiopia, at altitudes around 6,000 feet (1,800 m)

2573-515: The Renaissance, and was especially used in wall-mounted funerary art and later on Neoclassical pediments and public monuments. In the Buddhist and Hindu art of India and Southeast Asia, high relief can also be found, although it is not as common as low to mid-reliefs. Famous examples of Indian high reliefs can be found at the Khajuraho temples, with voluptuous, twisting figures that often illustrate

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2656-405: The background plane . When a relief is carved into a flat surface of stone (relief sculpture) or wood ( relief carving ), the field is actually lowered, leaving the unsculpted areas seeming higher. The approach requires a lot of chiselling away of the background, which takes a long time. On the other hand, a relief saves forming the rear of a subject, and is less fragile and more securely fixed than

2739-571: The background. From the Parthenon Frieze onwards, many single figures in large monumental sculpture have heads in high relief, but their lower legs are in low relief. The slightly projecting figures created in this way work well in reliefs that are seen from below, and reflect that the heads of figures are usually of more interest to both artist and viewer than the legs or feet. As unfinished examples from various periods show, raised reliefs, whether high or low, were normally "blocked out" by marking

2822-447: The composition, especially for scenes with many figures and a landscape or architectural background, in the same way that lighter colours are used for the same purpose in painting. Thus figures in the foreground are sculpted in high-relief, those in the background in low-relief. Low relief may use any medium or technique of sculpture, stone carving and metal casting being most common. Large architectural compositions all in low relief saw

2905-507: The distribution of aquatic plants is the availability of water. However, other abiotic factors may also control their distribution including nutrient availability, availability of carbon dioxide and oxygen, water temperature, characteristics of the substrate, water transparency, water movement, and salinity. Some aquatic plants are able to thrive in brackish, saline, and salt water . Also biotic factors like grazing, competition for light, colonization by fungi, and allelopathy are influencing

2988-411: The elements seen are "squashed" flatter. High relief thus uses essentially the same style and techniques as free-standing sculpture, and in the case of a single figure gives largely the same view as a person standing directly in front of a free-standing statue would have. All cultures and periods in which large sculptures were created used this technique in monumental sculpture and architecture. Most of

3071-508: The erotic Kamasutra positions. In the 9th-century Prambanan temple, Central Java , high reliefs of Lokapala devatas , the guardians of deities of the directions, are found. The largest high relief sculpture in the world is the Stone Mountain Confederate Memorial in the U.S. state of Georgia , which was cut 42 feet deep into the mountain, and measures 90 feet in height, 190 feet in width, and lies 400 feet above

3154-518: The final relief. In stone, as well as engraved gems, larger hardstone carvings in semi-precious stones have been highly prestigious since ancient times in many Eurasian cultures. Reliefs in wax were produced at least from the Renaissance . Carved ivory reliefs have been used since ancient times, and because the material, though expensive, cannot usually be reused, they have a relatively high survival rate, and for example consular diptychs represent

3237-530: The front the small variations in depth register as a three-dimensional image. Other versions distort depth much less. The term comes from the Italian basso rilievo via the French bas-relief ( French pronunciation: [baʁəljɛf] ), both meaning "low relief". The former is now a very old-fashioned term in English, and the latter term is becoming so. Low relief is a technique which requires less work, and

3320-471: The gods in gratitude. The pith of young shoots was eaten both cooked and raw. Its woody root made bowls and other utensils and was burned for fuel. From the stems were made reed boats (seen in bas-reliefs of the Fourth Dynasty showing men cutting papyrus to build a boat; similar boats are still made in southern Sudan ), sails, mats, cloth, cordage, and sandals. Theophrastus states that King Antigonus made

3403-529: The great majority of surviving examples, but minute, invisible remains of paint can usually be discovered through chemical means. The Ishtar Gate of Babylon , now in Berlin, has low reliefs of large animals formed from moulded bricks, glazed in colour. Plaster, which made the technique far easier, was widely used in Egypt and the Near East from antiquity into Islamic times (latterly for architectural decoration, as at

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3486-463: The ground. Sunk or sunken relief is largely restricted to the art of Ancient Egypt where it is very common, becoming after the Amarna period of Ahkenaten the dominant type used, as opposed to low relief. It had been used earlier, but mainly for large reliefs on external walls, and for hieroglyphs and cartouches . The image is made by cutting the relief sculpture itself into a flat surface to enhance

3569-479: The important functions performed by macrophyte is uptake of dissolved nutrients including nitrogen and phosphorus. Macrophytes are widely used in constructed wetlands around the world to remove excess N and P from polluted water. Beside direct nutrient uptake, macrophytes indirectly influence nutrient cycling , especially N cycling through influencing the denitrifying bacterial functional groups that are inhabiting on roots and shoots of macrophytes. Macrophytes promote

3652-472: The impression of three-dimensionality. In a simpler form, the images are usually mostly linear in nature, like hieroglyphs, but in most cases the figure itself is in low relief, but set within a sunken area shaped round the image, so that the relief never rises beyond the original flat surface. In some cases the figures and other elements are in a very low relief that does not rise to the original surface, but others are modeled more fully, with some areas rising to

3735-592: The insides of the folding wings of multi-panel altarpieces . The revival of low relief, which was seen as a classical style, begins early in the Renaissance; the Tempio Malatestiano in Rimini , a pioneering classicist building, designed by Leon Battista Alberti around 1450, uses low reliefs by Agostino di Duccio inside and on the external walls. Since the Renaissance plaster has been very widely used for indoor ornamental work such as cornices and ceilings, but in

3818-647: The leaves can photosynthesize more efficiently in air and competition from submerged plants but often, the main aerial feature is the flower and the related reproductive process. The emergent habit permits pollination by wind or by flying insects . There are many species of emergent plants, among them, the reed ( Phragmites ), Cyperus papyrus , Typha species, flowering rush and wild rice species. Some species, such as purple loosestrife , may grow in water as emergent plants but they are capable of flourishing in fens or simply in damp ground. Submerged macrophytes completely grow under water with roots attached to

3901-429: The leaves on the plant that grew while above water, along with oxygen levels being higher in the portion of the plant grown underwater versus the sections that grew in their terrestrial environment. This is considered a form of phenotypic plasticity as the plant, once submerged, experiences changes in morphology better suited to their new aquatic environment. However, while some terrestrial plants may be able to adapt in

3984-430: The leaves' thickness, shape and density and are the main factor responsible for the greatly reduced rate of gaseous transport across the leaf/water boundary and therefore greatly inhibit transport of carbon dioxide. To overcome this limitation, many aquatic plants have evolved to metabolise bicarbonate ions as a source of carbon. Environmental variables affect the instantaneous photosynthetic rates of aquatic plants and

4067-816: The many grand figure reliefs in Ancient Greek sculpture used a very "high" version of high relief, with elements often fully free of the background, and parts of figures crossing over each other to indicate depth. The metopes of the Parthenon have largely lost their fully rounded elements, except for heads, showing the advantages of relief in terms of durability. High relief has remained the dominant form for reliefs with figures in Western sculpture, also being common in Indian temple sculpture. Smaller Greek sculptures such as private tombs, and smaller decorative areas such as friezes on large buildings, more often used low relief. Hellenistic and Roman sarcophagus reliefs were cut with

4150-474: The occurrence of macrophytes. Aquatic plants have adapted to live in either freshwater or saltwater. Aquatic vascular plants have originated on multiple occasions in different plant families; they can be ferns or angiosperms (including both monocots and dicots ). The only angiosperms capable of growing completely submerged in seawater are the seagrasses . Examples are found in genera such as Thalassia and Zostera . An aquatic origin of angiosperms

4233-551: The open air (if inside caves, whether natural or human-made, they are more likely to be called "rock-cut"). This type is found in many cultures, in particular those of the Ancient Near East and Buddhist countries. A stele is a single standing stone; many of these carry reliefs. The distinction between high and low relief is somewhat subjective, and the two are very often combined in a single work. In particular, most later "high reliefs" contain sections in low relief, usually in

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4316-453: The original surface. This method minimizes the work removing the background, while allowing normal relief modelling. The technique is most successful with strong sunlight to emphasise the outlines and forms by shadow, as no attempt was made to soften the edge of the sunk area, leaving a face at a right-angle to the surface all around it. Some reliefs, especially funerary monuments with heads or busts from ancient Rome and later Western art, leave

4399-428: The outline of the figure and reducing the background areas to the new background level, work no doubt performed by apprentices (see gallery). A low relief is a projecting image with a shallow overall depth, for example used on coins, on which all images are in low relief. In the lowest reliefs the relative depth of the elements shown is completely distorted, and if seen from the side the image makes no sense, but from

4482-474: The papyrus culms can measure up to 29.5 feet (9.0 m) in length, with an additional 18 inches (46 cm) for the inflorescence (a spicate umbel; i.e. each of the up to one thousand rays of the umbel terminates in a spike of small flowers) for a total height of 31 feet (9.4 m). Each culm is a single internode ‍ — ‍ the longest known of any plant. At Lake Naivasha, the culms, triangular in cross-section, were as much as 7 inches (18 cm) on

4565-412: The photosynthetic enzymes pigments. In water, light intensity rapidly decreases with depth. Respiration is also higher in the dark per the unit volume of the medium they live in. Fully submerged aquatic plants have little need for stiff or woody tissue as they are able to maintain their position in the water using buoyancy typically from gas filled lacunaa or turgid Aerenchyma cells. When removed from

4648-463: The plane is only very slightly lower than the sculpted elements. There is also sunk relief , which was mainly restricted to Ancient Egypt ( see below ). However, the distinction between high relief and low relief is the clearest and most important, and these two are generally the only terms used to discuss most work. The definition of these terms is somewhat variable, and many works combine areas in more than one of them, rarely sliding between them in

4731-563: The plants are not at risk of losing water through the stomata and therefore face no risk of dehydration. For carbon fixation, some aquatic angiosperms are able to uptake CO 2 from bicarbonate in the water, a trait that does not exist in terrestrial plants. Angiosperms that use HCO 3 - can keep CO 2 levels satisfactory, even in basic environments with low carbon levels. Due to their environment, aquatic plants experience buoyancy which counteracts their weight. Because of this, their cell covering are far more flexible and soft, due to

4814-454: The restriction or banning of the trade in invasive alien plants. Bas-relief Relief is a sculptural method in which the sculpted pieces remain attached to a solid background of the same material. The term relief is from the Latin verb relevare , to raise (lit. to lift back). To create a sculpture in relief is to give the impression that the sculpted material has been raised above

4897-416: The rigging of his fleet of papyrus, an old practice illustrated by the ship's cable, wherewith the doors were fastened when Odysseus slew the suitors in his hall ( Odyssey xxi. 390). The adventurer Thor Heyerdahl had a boat built for him of papyrus, Ra , in an attempt to demonstrate that ancient African or Mediterranean people could have reached America. He was unsuccessful with this boat. Fishermen in

4980-417: The round". Most ancient architectural reliefs were originally painted, which helped to define forms in low relief. The subject of reliefs is for convenient reference assumed in this article to be usually figures, but sculpture in relief often depicts decorative geometrical or foliage patterns, as in the arabesques of Islamic art , and may be of any subject. Rock reliefs are those carved into solid rock in

5063-451: The sculpted form from the field, for which the Italian and French terms are still sometimes used in English. The full range includes high relief (Italian alto-rilievo , French haut-relief ), where more than 50% of the depth is shown and there may be undercut areas, mid-relief (Italian mezzo-rilievo ), low relief (Italian basso-rilievo , French: bas-relief ), and shallow-relief (Italian rilievo schiacciato ), where

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5146-514: The sedimentation of suspended solids by reducing the current velocities, impede erosion by stabilising soil surfaces. Macrophytes also provide spatial heterogeneity in otherwise unstructured water column. Habitat complexity provided by macrophytes tends to increase diversity and density of both fish and invertebrates. The additional site-specific macrophytes' value provides wildlife habitat and makes treatment systems of wastewater aesthetically satisfactory. Some aquatic plants are used by humans as

5229-426: The short-term to an aquatic habitat, it may not be possible to reproduce underwater, especially if the plant usually relies on terrestrial pollinators . Based on growth form, macrophytes can be characterised as: An emergent plant is one which grows in water but pierces the surface so that it is partially exposed to air. Collectively, such plants are emergent vegetation . This habit may have developed because

5312-510: The soil line, the younger parts of the rhizome are covered by red-brown, papery, triangular scales, which also cover the base of the culms. Technically, these are reduced leaves , so strictly it is not quite correct to call this plant fully "leafless". Egyptians used the plant (which they called aaru , or the subspecies C. p. papyrus , which came very close to extinction, but was rediscovered in 1968.) for many purposes, including for making papyrus paper. Its name has an uncertain origin, but

5395-492: The specialized root / rhizoid system of plants. Instead, seaweeds have holdfasts that only serve as anchors and have no absorptive functions . Aquatic plants require special adaptations for prolonged inundation in water, and for floating at the water surface. The most common adaptation is the presence of lightweight internal packing cells, aerenchyma , but floating leaves and finely dissected leaves are also common. Aquatic plants only thrive in water or in soil that

5478-607: The stem and root of Ludwigia adscendens , as well as those of the fruit, leaf and stem of Monochoria hastata were found to have lipoxygenase inhibitory activity. Hot water extract prepared from the leaf of Ludwigia adscendens exhibits alpha-glucosidase inhibitory activity more potent than that of acarbose . Macrophytes have an essential role in some forms of wastewater treatment, most commonly in small scale sewage treatment using constructed wetlands or in polishing lagoons for larger schemes. The introduction of non-native aquatic plants has resulted in numerous examples across

5561-616: The substrate (e.g. Myriophyllum spicatum ) or without any root system (e.g. Ceratophyllum demersum ). Helophytes are plants that grow partly submerged in marshes and regrow from buds below the water surface. Fringing stands of tall vegetation by water basins and rivers may include helophytes. Examples include stands of Equisetum fluviatile , Glyceria maxima , Hippuris vulgaris , Sagittaria , Carex , Schoenoplectus , Sparganium , Acorus , yellow flag ( Iris pseudacorus ), Typha and Phragmites australis . Floating-leaved macrophytes have root systems attached to

5644-769: The substrate or bottom of the body of water and with leaves that float on the water surface. Common floating leaved macrophytes are water lilies (family Nymphaeaceae ), pondweeds (family Potamogetonaceae ). Free-floating macrophytes are found suspended on water surface with their root not attached to the substrate, sediment , or bottom of the water body. They are easily blown by air and provide breeding ground for mosquitoes. Examples include Pistia spp. commonly called water lettuce, water cabbage or Nile cabbage. The many possible classifications of aquatic plants are based upon morphology. One example has six groups as follows: Macrophytes perform many ecosystem functions in aquatic ecosystems and provide services to human society. One of

5727-459: The surface of the water. Some still-water plants can alter their position in the water column at different seasons. One notable example is Water soldier which rests as a rootless rosette on the bottom of the water body but slowly floats to the surface in late Spring so that its inflorescence can emerge into the air. While it is ascending through the water column it produces roots and vegetative daughter plants by means of rhizomes . When flowering

5810-500: The surface. Although most aquatic angiosperms can reproduce by flowering and setting seeds, many have also evolved to have extensive asexual reproduction by means of rhizomes , turions , and fragments in general. Submerged aquatic plants have more restricted access to carbon as carbon dioxide compared to terrestrial plants. They may also experience reduced light levels. In aquatic plants diffuse boundary layers (DBLs) around submerged leaves and photosynthetic stems vary based on

5893-463: The technique are described as "in relief", and, especially in monumental sculpture , the work itself is "a relief". Reliefs are common throughout the world on the walls of buildings and a variety of smaller settings, and a sequence of several panels or sections of relief may represent an extended narrative. Relief is more suitable for depicting complicated subjects with many figures and very active poses, such as battles, than free-standing "sculpture in

5976-443: The transition from an aquatic to terrestrial habitat. Terrestrial plants no longer had unlimited access to water and had to evolve to search for nutrients in their new surroundings as well as develop cells with new sensory functions, such as statocytes . Terrestrial plants may undergo physiological changes when submerged due to flooding. When submerged, new leaf growth has been found to have thinner leaves and thinner cell walls than

6059-689: The water body. Such problems may be the result of excessive turbidity , herbicides , or salination . Conversely, overly high nutrient levels may create an overabundance of macrophytes, which may in turn interfere with lake processing . Macrophyte levels are easy to sample, do not require laboratory analysis, and are easily used for calculating simple abundance metrics. Phytochemical and pharmacological researches suggest that freshwater macrophytes, such as Centella asiatica , Nelumbo nucifera , Nasturtium officinale , Ipomoea aquatica and Ludwigia adscendens , are promising sources of anticancer and antioxidative natural products. Hot water extracts of

6142-564: The water flow, capture sediments and trap pollutants . Excess sediment will settle into the stream bed due to the reduced flow rates, and some aquatic plants also have symbiotic microbes capable of nitrogen fixation and breaking down the pollutants trapped and/or absorbed by the roots. Historically, aquatic plants have been less studied than terrestrial plants , and management of aquatic vegetation has become an increasingly interested field as means to reduce agricultural pollution of water bodies . The principal factor controlling

6225-437: The water surface. Aquatic plants are important primary producers and are the basis of food web for many aquatic fauna , especially wetland species. They compete with phytoplanktons for excess nutrients such as nitrogen and phosphorus , thus reducing the prevalence of eutrophication and harmful algal blooms , and have a significant effect on riparian soil chemistry as their leaves , stems and roots slow down

6308-618: The water, such plants are typically limp and lose turgor rapidly. Those living in rivers do, however, need sufficient structural xylem to avoid being damaged by fast flowing water and they also need strong mechanisms of attachment to avoid being uprooted by river flow. Many fully submerged plants have finely dissected leaves, probably to reduce drag in rivers and to provide a much increased surface area for interchange of minerals and gasses. Some species of plants such as Ranunculus aquatilis have two different leaf forms with finely dissected leaves that are fully submerged and entire leaves on

6391-560: The wetter parts of Africa, but it has become rare in the Nile Delta . In deeper waters, it is the chief constituent of the floating, tangled masses of vegetation known as sudd . It also occurs in Madagascar , and some Mediterranean areas such as Sicily and the Levant . The "feather-duster" flowering heads make ideal nesting sites for many social species of birds. As in most sedges, pollination

6474-419: The whole body of many ponds to the almost total exclusion of other plants and wildlife Other notable invasive plant species include floating pennywort , Curly leaved pondweed , the fern ally Water fern and Parrot's feather . Many of these invasive plants have been sold as oxygenating plants for aquaria or decorative plants for garden ponds and have then been disposed of into the environment. In 2012,

6557-717: The works usually being described as low relief instead. The typical traditional definition is that only up to half of the subject projects, and no elements are undercut or fully disengaged from the background field. The depth of the elements shown is normally somewhat distorted. Mid-relief is probably the most common type of relief found in the Hindu and Buddhist art of India and Southeast Asia . The low to mid-reliefs of 2nd-century BCE to 6th-century CE Ajanta Caves and 5th- to 10th-century Ellora Caves in India are rock reliefs. Most of these reliefs are used to narrate sacred scriptures, such as

6640-416: The world of such plants becoming invasive and frequently dominating the environments into which they have been introduced. Such species include Water hyacinth which is invasive in many tropical and sub-tropical locations including much of the southern US, many Asian countries and Australia. New Zealand stonecrop is a highly invasive plant in temperate climates spreading from a marginal plant to encompassing

6723-564: Was also a native plant of the Niger River and the Euphrates . Neither the explorer Peter Forsskål , an apostle of Carl Linnaeus , in the 18th century, nor the Napoleonic expedition saw it in the delta. Aside from papyrus, several other members of the genus Cyperus may also have been involved in the multiple uses Egyptians found for the plant. Its flowering heads were linked to make garlands for

6806-635: Was rendered in Hellenistic Greek as πάπυρος. In the Nile Delta , Cyperus papyrus was widely cultivated in ancient times. It is for example depicted on a restored stucco fragment from the palace of Amenhotep III near the present-day village of Malkata . Currently, only a small population remains in Egypt, in Wadi El Natrun . Theophrastus 's History of Plants (Book iv. 10) states that it grew in Syria , and according to Pliny's Natural History , it

6889-767: Was used for various purposes such as baskets, sandals, blankets, medicine, incense, and boats. The woody root was used to make bowls and utensils, and was burned for fuel. The Papyrus Ebers refers to the use of soft papyrus tampons by Egyptian women in the 15th century BCE. Egyptians made efficient use of all parts of the plant. Papyrus was an important "gift of the Nile" which is still preserved and perpetuated in Egyptian culture. Aquatic plant Although seaweeds , which are large multicellular marine algae , have similar ecological functions to aquatic plants such as seagrass , they are not typically referred to as macrophytes as they lack

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