Torpedograss is native to both the Old and New Worlds [44], with reported sources of origin including southern Europe [105], the Mediterranean, the Arabian Peninsula, Israel [29], northern [29], tropical, and southern Africa [29,105], Argentina [29], and Australia [29,109].
Torpedograss was introduced to the Gulf Coast of the United States sometime prior to 1876, when it was first collected in Alabama [65]. It was introduced in seed for forage crops [65,69]. Seed may also have been transported via ballast from sailing vessels carrying lumber from the Mediterranean [109]. In the early 1900s the United States Department of Agriculture imported and distributed torpedograss seed to provide forage for cattle [69]. By 1950, it was planted in nearly every southern Florida county and in a few central and north-central counties [65]. It subsequently escaped cultivation [29].
As of this writing (2011), torpedograss occurs in tropical and subtropical regions throughout the world from latitude 35 °S to 43 °N [49]. In the United States, the distribution of torpedograss is limited to the southern Atlantic coast from North Carolina south and west to Texas, and isolated populations in California and Hawaii [58]. It also occurs in Mexico [11]. Plants Database provides a distributional map of torpedograss.
It is not clear what fire regime torpedograss is best adapted to. Observations from Florida suggest that fire severity may impact torpedograss survival, with high-severity fires potentially killing torpedograss rhizomes [7]. Repeated fires have resulted in torpedograss mortality in some situations, but torpedograss has survived repeated fires under other conditions (see Plant response to fire). Alteration of local fuel characteristics following torpedograss invasion may change FIRE REGIMES.
In North America, torpedograss invasion is limited to relatively few plant communities, many of which lack fire regime information. See the Fire Regime Table for available information on FIRE REGIMES of vegetation communities in which torpedograss may occur. Find further fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Fire adaptations: Torpedograss exhibits some characteristics that enable it to survive fire. It is rhizomatous (see Vegetative regeneration), and managers report that rhizomes below the soil surface generally survive fire ([7], personal communication [6]). Torpedograss also often establishes in moist to wet areas where rhizomes are generally protected from fire damage, though aerial portions may burn [7]. Torpedograss has been observed sprouting following fire [45,46,92,98] (see Plant response to fire, below), herbicide application [14,39,54,59,83,92], grazing [79], cutting, [19,39], and plowing or disking [83,92]. However, rhizomes show some sensitivity to heat, so high-severity fire may kill rhizomes [7]. Growth chamber experiments showed that rhizomes died after 1 hour of immersion in heated water (>140 °F (60 °C)) [109].
As of this writing (2011), the limited available information suggests that torpedograss is not particularly adapted to establishing in burned areas via dispersed seeds or from the soil seed bank (see Seed production, Seed banking, and Germination).
Plant response to fire: The available information suggests that torpedograss biomass is reduced following fire but plants often survive and sprout quickly. Mortality may occur in areas where local conditions (e.g., moisture, soil depth) expose rhizomes to heat. Postfire recovery is likely, though recovery may be limited in areas that experience flooding or are treated with herbicides.
Several sources report torpedograss surviving and sprouting soon after fire in Florida. One manager in Florida observed that torpedograss exhibits faster postfire recovery than native plants, allowing it to dominate burned areas at the expense of native vegetation (personal communication [6]). Managers report that in areas around Lake Okeechobee where water depth was approximately 2 to 3 inches (5-8 cm), torpedograss recovered "rapidly and vigorously" following initial biomass reduction after fire, with new growth sprouting from previously dormant buds [7]. After a May prescribed fire near East Lake Tohopekaliga, Florida, torpedograss sprouted "immediately" in areas that were burned or burned and disked. Rhizome biomass was reduced by 66% in burned areas and 93% in burned and disked areas 100 days after treatment but recovered to approximately 20% of pretreatment levels after 250 days in both treatments [92]. Two studies provide information on aboveground growth after wildfire in the Lake Okeechobee region. One month after an August wildfire, the average torpedograss height in burned areas was 4 to 8 inches (10-20 cm) compared to ≥30 inches (70 cm) in unburned areas [45]. Six weeks after top-kill from a February wildfire, torpedograss height averaged 8 inches (20 cm) [46].
In Florida, managers observed torpedograss mortality in areas exposed to unusual drought conditions, where water levels receded 2 to 3 feet (0.6-0.9 m) below the surface of the ground. Fire consumed both aboveground vegetation and the upper, dry, compacted peat layers to a depth of 3 to 4 inches (8-10 cm). Torpedograss mortality was also observed following a prescribed fire in 1990 and a wildfire in 1997; in both years, water levels were below the ground's surface [7]. However, dry conditions do not always result in torpedograss mortality. In 2007, torpedograss populations in marshes around Lake Okeechobee survived repeated fires during a record low-water period (personal communication [6]).
Flooding after fire may also lead to torpedograss mortality. One manager from Florida reported that he expected torpedograss populations to respond well and potentially expand following fire, depending on postfire water levels; he observed torpedograss mortality and a subsequent population decline in an area that experienced flooding for months following fire (personal communication [6]). In the Florida Everglades, torpedograss cover was significantly lower 1 year after a mixed-severity prescribed fire in areas flooded after treatment (P<0.001) [98]. See Fire Management Considerations for more information on this study.
Herbicide treatment following fire may reduce torpedograss populations. See Fire Management Considerations for more information.
Long-term impacts of fire on torpedograss have not been reported as of this writing (2011).
The limited information available (2011) suggests that torpedograss populations develop heavy fuel loads that may alter fire characteristics.
In Florida, torpedograss grows in dense stands and may comprise 80% of the biomass of an area where it establishes (personal communication [6]). Along the shores of Lake Kariba, Zimbabwe, the average standing crop biomass of torpedograss was 7,620 ± 21.8 kg/ha with an average moisture content of 72.91% ± 0.24 (sampled February to May) [16]. Dead leaves and culms of torpedograss accumulate in areas without grazing [79].
One manager from Florida believes that populations of torpedograss accumulate much more fuel than the native plant communities that it replaces, particularly in sawgrass (Cladium jamaicense) and spikerush prairies and American white waterlily sloughs. The increased biomass may lead to "hotter" fires resulting in higher mortality of native species, particularly sawgrass (personal communication [6]).
Torpedograss has been widely planted as forage for livestock and may have some nutritional value to wildlife.
Palatability and nutritional value: Torpedograss has been planted throughout the world as forage for domestic livestock [2,44,65,69,79]. A nonnative species guide reports that, though used for pasturage, torpedograss has relatively low nutritional value, protein content, and palatability compared to other grasses. Its advantage as a forage grass is that it is relatively palatable when young and can withstand heavy grazing and trampling [49]. It can be fed to cattle either green or as hay [31]. However, torpedograss was reported as poisonous to horses in Florida [92,109].
Torpedograss may have some value as food for wildlife. Populations of torpedograss near Lake Okeechobee supported a diverse arthropod and nematode fauna, and plants were not limited by invertebrate herbivory or damage [29]. In feeding trials in Florida, it was consumed by the nonnative channeled apple snail (Pomacea insularum) [4,5]. On the Mississippi River delta, both above- and belowground vegetation of torpedograss was eaten by snow geese and brants in the fall [72]. It was eaten by redbread tilapia (Tilapia rendalli) in Lake Kariba in Zimbabwe [16]. Seeds of torpedograss were found in fecal pellets of wild spur-thighed tortoises in Spain [26].
Cover value: No information is available on this topic.
Torpedograss occurs in both aquatic and terrestrial plant communities [44], including coastal sand, wetland, and forested plant communities.
Coastal sand plant communities: Torpedograss establishes in coastal sand plant communities around the Gulf of Mexico, including sand dunes [11,67,68,74,77,81], ridges [67], plains [11], and beaches [68]. Torpedograss occurred in coastal dune communities along the northern Gulf Coast including Texas, Mississippi, Louisiana and the west coast of Florida. Common associates included turtleweed (Batis maritima), saltgrass (Distichlis spicata), marsh fimbry (Fimbristylis castanea), largeleaf pennywort (Hydrocotyle bonariensis), and dwarf saltwort (Salicornia bigelovii) [77]. On a barrier island between the Mississippi Sound and the Gulf of Mexico, torpedograss occurred on sand dunes dominated by seaoats
(Uniola paniculata), moist dunes with Le Conte's flatsedge (Cyperus lecontei) and largeleaf pennywort, and in a coastal sand frostweed-woody goldenrod (Helianthemum arenicola-Chrysoma pauciflosculosa) plant community [81]. On an island off the coast of Louisiana, torpedograss established on sandy, compacted turf with erect centella (Centella erecta) and starrush whitetop (Rhynchospora colorata) [10]. Herbarium records from Texas documented torpedograss occurring between a seawall and saltgrass flats [36]. In coastal areas of Mexico, torpedograss occurred on sand dunes and sandy plains with slender grama (Bouteloua repens), sideoats grama (B.
curtipendula), Acapulco grass (B. dimorpha), bahiagrass (Paspalum notatum), hilograss (P. conjugatum), and mesosetum grasses (Mesosetum spp.) [11].
Wetlands and riparian areas: Torpedograss establishes in a variety of moist plant communities, including wetlands [13,17,18,30,35,36,76,80,84,113], wet prairies [24,33,34,61,73,113], and in or around water bodies [29,88,93,113].
Wetlands: In Gulf Coast freshwater marshes, torpedograss occurred with alligatorweed (Alternanthera philoxeroides), herb of grace (Bacopa monnieri), fragrant flatsedge (Cyperus odoratus), common water hyacinth (Eichhornia crassipes), spikerush (Eleocharis sp.), hydrocotyle (Hydrocotyle sp.), sprangletop
(Leptochloa sp.), maidencane (Panicum hemitomon), common reed (Phragmites
australis), bulltongue arrowhead (Sagittaria lancifolia ssp. media), saltmeadow cordgrass (Spartina patens), cattail (Typha sp.), hairypod cowpea
(Vigna repens), and giant cutgrass (Zizaniopsis miliacea) [30]. On a barrier island in the Gulf Islands National Seashore, Florida, torpedograss occurred in freshwater marshes with southern umbrella-sedge (Fuirena scirpoidea) and broomsedge bluestem (Andropogon virginicus) [76]. In Florida, torpedograss dominated part of a 1-year-old wetland constructed for wastewater treatment but 2 years later had been replaced by pickerelweed (Pontederia cordata), bulltongue arrowhead, and Olney's threesquare bulrush [13]. In southwestern peninsular Florida, torpedograss was
an occasional species in disturbed wet areas and seasonal ponds and sloughs occurring within dry prairies with saw-palmetto (Serenoa repens); in South Florida slash pine (Pinus elliottii var. densa) flatwoods; and in river-corridor hammocks with live oak (Quercus virginiana), laurel oak (Q. laurifolia), and cabbage palmetto (Sabal palmetto) [55].
On the Mississippi River delta, torpedograss occurred in coastal marsh plant communities containing mixtures of common reed [17,18,84], saltmeadow cordgrass [17], smooth cordgrass (S.
alterniflora), cattails (Typha spp.), Olney's threesquare bulrush (Schoenoplectus americanus), and giant cutgrass [84]. In the same region, torpedograss occurred on mud flats with giant cutgrass, seacoast bulrush (Bolboschoenus robustus), smooth cordgrass, and narrow-leaved cattail (Typha angustifolia) [72]. In southeastern Louisiana, torpedograss occurred in thick-mat floating-marsh plant communities. Species composition varied, but these communities contained
monocultures or mixtures of bulltongue arrowhead (Sagittaria lancifolia), cattails, Olney's threesquare bulrush, cordgrass (Spartina spp.), giant cutgrass, and common reed [80]. Herbarium records from Texas documented torpedograss occurring in a small freshwater marsh with spadeleaf
(Centella asiatica), jointed flatsedge (Cyperus articulatus), tapertip flatsedge
(C. acuminatus), velvet panicum (Dichanthelium scoparium), Virginia buttonweed
(Diodia virginiana), and mountain spikerush (Eleocharis montana) [36].
Wet prairies: In southeastern Florida, torpedograss occurred in wet prairies characterized by St. Johnswort (Hypericum spp.), yelloweyed grass (Xyris spp.), spadeleaf, rush (Juncus spp.), panicgrass (Panicum spp.), and Tracy's beaksedge
(Rhynchospora tracyi) [73]. Torpedograss occurred infrequently and at low cover in wet prairies in west-central Florida. Common species included dwarf crabgrass (Digitaria serotina), broadleaf carpetgrass (Axonopus compressus), knotgrass (Paspalum distichum), and pineland threeawn (Aristida stricta) [24]. In southwestern Louisiana, torpedograss occurred in plant communities of intermixed prairie and cheniere (ridges made of shell fragments and sand that rise above sea level in coastal marshes). Species commonly found in prairies included golden tickseed (Coreopsis tinctoria), rosy camphorweed (Pluchea rosea), blackeyed Susan (Rudbeckia hirta var.pulcherrima), marsh flatsedge (Cyperus pseudovegetus), keeled bulrush (Isolepis koilolepis), slickseed fuzzybean (Strophostyles leiosperma), tapertip rush (Juncus acuminatus), forked rush (J. dichotomus), gaping grass (Panicum hians), brownseed paspalum (Paspalum plicatulum), and prairie wedgescale (Sphenopholis obtusata). Common species on chenieres included live oak, sugarberry (Celtis laevigata), and Hercules' club
(Zanthoxylum clava-herculis) [34]. Torpedograss occurred in smooth cordgrass prairies along the Mississippi River delta [33] and in Louisiana and Texas [33,61].
In or around water bodies: In and around Lake Okeechobee in Florida, torpedograss established with Gulf Coast spikerush (Eleocharis cellulosa), American white waterlily (Nymphaea odorata) [93], and little sand cordgrass (Spartina bakeri) [29]. Herbarium records from Florida documented torpedograss occurring in and around a pond with Spanish needles (Bidens bipinnata), shortleaf spikesedge (Kyllinga brevifolia), taperleaf water horehound (Lycopus rubellus), and baldcypress (Taxodium distichum) [113]. Torpedograss occurred in a disturbed shoreline plant community in southeastern Alabama. The shoreline plant
community contained yellowfruit sedge (Carex annectens) and southern waxy sedge
(C. glaucescens). Woody species included wax-myrtle (Myrica cerifera) and black
tupelo (Nyssa sylvatica) [88].
Forested plant communities: Torpedograss establishes in some areas with a tree canopy. Herbarium records from Florida documented torpedograss occurring along a road in sand pine (Pinus clausa) scrub and in slightly disturbed areas in
white sand scrub associated with coastal plain honeycombhead (Balduina angustifolia), blue maidencane (Amphicarpum muhlenbergianum), lopsided Indiangrass (Sorghastrum secundum), jeweled blue-eyed grass (Sisyrinchium xerophyllum); in oak (Quercus) woods, and in pinelands with cabbage palmetto, serenoa (Serenoa), and sweetgale (Myrica) [113].
At the Cumberland Island National Seashore off the coast of southern Georgia, torpedograss was restricted to open areas along roads bisecting maritime hammocks and pine (Pinus)-oak forests. Live oak dominated maritime hammocks, while loblolly pine (Pinus taeda), slash pine (P.
elliottii), longleaf pine (P. palustris), and live oak occurred in pine-oak forest [116].
On a barrier island between the Mississippi Sound and the Gulf of Mexico, torpedograss occurred in open forests with slash pine, sand live oak (Q. geminata), and myrtle oak (Q. myrtifolia) [81]. Herbarium records from Texas documented torpedograss as common in a drainage ditch along the edge
of a patch of forest dominated by sugarberry and nonnative Chinese tallow
(Triadica sebifera)[36].
Ƙafifiya (ƙafíífíyàà) (Panicum repens) shuka ne.[1]
Ƙafifiya (ƙafíífíyàà) (Panicum repens) shuka ne.
Panicum repens is a species of grass known by many common names, including torpedograss, creeping panic, panic rampant, couch panicum, wainaku grass, quack grass, dog-tooth grass, and bullet grass. Its exact native range is obscure. Sources suggest that the grass is native to "Africa and/or Asia",[1] "Europe or Australia",[2] "Eurasia",[3] "Australia",[4] "Europe, Asia, and Africa",[5] or other specific regions, including the Mediterranean, Israel, and Argentina.[6] It is present in many places as an introduced species and often a noxious weed. It has been called "one of the world's worst weeds."[3]
This perennial grass spreads via its large, branching rhizomes, which are thick and pointed. The pointed shape of the rhizome tip gives the plant the name torpedograss. The rhizomes creep along the ground or float in water, forming floating mats. They can reach a length of 6 m (20 ft) and a soil depth of 7 m (23 ft), and they can form a mat 15 cm (5.9 in) thick. The spreading rhizomes sprout repeatedly to form colonies of stems.[6] The stems are 20 to 90 cm (7.9 to 35.4 in) tall,[7] sometimes reaching 1 m (3 ft 3 in). They grow erect or bend down. The leaves are stiff and straight, linear in shape, and flat or folded. They are sometimes white in color and waxy in texture. The inflorescence is a loose panicle of branches bearing small spikelets 2 to 3 mm (0.079 to 0.118 in) long.[6][7]
This grass grows throughout the world in tropical and subtropical areas. It was introduced to the United States in seed for forage grasses and probably in ballast water from ships. It was also imported by the United States Department of Agriculture to grow as a forage grass for cattle. It was deliberately planted throughout South Florida and it easily escaped cultivation,[6] eventually becoming "one of the most serious weeds in Florida," spreading to more than 70% of the waterways in the state.[1] In Lake Okeechobee, it has invaded more than 16,000 acres of marsh.[6] It displaces native plants,[8] growing colonially in thick, monotypic stands.[3] Dense mats or stands of the grass cause hypoxia in the water.[6] Torpedograss management in flood-control systems costs an estimated US$2 million per year.[3]
The plant is established in sandy coastal habitat on the United States' Gulf Coast, such as beaches and dunes, from Florida to Texas, where it occurs with beach plants such as turtleweed (Batis maritima), saltgrass (Distichlis spicata), marsh fimbry (Fimbristylis castanea), largeleaf pennywort (Hydrocotyle bonariensis), and dwarf saltwort (Salicornia bigelovii). It grows on many barrier islands. It grows in many types of wetland habitat, in and out of the water. It grows in freshwater marshes, salt marshes, mud flats, wet prairies, tide pools, bogs, and lakesides. It also invades drier habitat, such as coastal pine forests and white sand scrub. It easily moves into disturbed and cultivated areas such as ditches and canals.[6] It is a nuisance in sod production.[1] In Hawaii, it is a weed of sugarcane (Saccharum officinarum).[3][5] In other areas, it can be found in turf and orchards.[5] In the Florida turfgrass industry, it is the second-worst weed known.[9] The grass can grow in a variety of habitats, but it does not tolerate cold and it is rarely found above subtropical latitudes or at altitude.[6]
The grass spreads primarily via its rhizome. It has been noted to grow 1.3 cm (0.51 in) in length per day. The stems and rhizomes also produce tillers. The rhizome can endure drying and flooding. Dry or wet conditions may reduce the number of shoots produced by the rhizome, but they do not kill it. The rhizome can disperse when parts of it break off and drop onto the substrate elsewhere, anchoring and putting up new shoots. The plant survives and sprouts after herbicide application, grazing, cutting, plowing or disking, and burning. The grass rarely reproduces by seed.[6] It has been noted to reproduce by seed in Portugal,[9] but does not do so in the United States,[10] and it was described as "incapable of fruiting" in Japan. Seeds are sometimes observed but they are apparently rarely viable, with many studies describing zero germination.[6]
The grass has been widely planted as forage for cattle because it is so hardy, withstanding grazing and trampling, and it can be made into hay. However, it is not one of the more palatable or nutritious grasses. It is also good for erosion control because it binds the soil. Indeed, it is still recommended for planting along shorelines to stabilize them.[11]
Torpedograss in a ditch Panicum repens is a species of grass known by many common names, including torpedograss, creeping panic, panic rampant, couch panicum, wainaku grass, quack grass, dog-tooth grass, and bullet grass. Its exact native range is obscure. Sources suggest that the grass is native to "Africa and/or Asia", "Europe or Australia", "Eurasia", "Australia", "Europe, Asia, and Africa", or other specific regions, including the Mediterranean, Israel, and Argentina. It is present in many places as an introduced species and often a noxious weed. It has been called "one of the world's worst weeds."
Panicum repens, le panic rampant ou millet rampant, est une espèce de plantes monocotylédones de la famille des Poaceae (graminées), sous-famille des Panicoideae, originaire des régions tropicales et subtropicales de l'Ancien Monde.
Ce sont des plantes herbacées vivaces, aux rhizomes allongés, aux tiges (chaumes) dressées ou géniculées ascendantes, longues de 30 à 100 cm. Ces plantes qui poussent dans les zones humides, au bord des cours d'eau, se sont répandues dans toutes les régions tropicales et subtropicales du Monde.
Ce sont des adventices envahissantes, difficiles à éradiquer dès lors qu'elles se sont établies.
Panicum repens est une plante herbacée vivace aux rhizomes allongés, parfois stolonifère. Les chaumes dressés ou géniculés ascendants peuvent atteindre 30 cm à 1 m de long. Les feuilles alternes, distiques, présente une ligule constituée d'une membrane ciliée, un limbe coriace, raide, glauque, plat ou enroulé de 7 à 25 cm de long sur 2 à 8 mm de large[2].
L'inflorescence est une panicule oblongue, ouverte, lâche, de 5 à 20 cm de long. Les épillets solitaires, pédicellés, se composent de deux fleurons, un fleuron basal stérile et un fleuron fertile, sans extension du rachillet. Les épillets sont ovales, comprimés dorsalement et mesurent 2,5 à 3 mm de long. Ils se détachent entier à maturité. Ils sont sous-tendus par deux glumes dissemblables, la glume supérieure de longueur égale à celle de l'épillet, la glume inférieure nettement plus courte[2].
L'aire de répartition originelle de Panicum repens s'étend dans l'Ancien Monde, mais son extension précise est incertaine. Elle engloberait une grande partie de l'Afrique ainsi que la Macaronésie (Madère, Canaries), l'Asie tempérée (de la péninsule arabique et du Proche-Orient à la Chine et à l'Extrême-Orient), et l'Asie tropicale (du sous-continent indien à l'Indonésie et aux Philippines), ainsi que l'Europe méridionale, de la Grèce au Portugal[3].
L'espèce est naturalisée notamment aux Açores, aux Seychelles, en Australie, en Amérique du Nord (Mexique, sud des États-Unis), en Amérique centrale (Belize, Antilles), et Amérique du Sud (Brésil, Argentine), et dans les îles du Pacifique[3].
Aux États-Unis, Panicum repens s'est naturalisée en Californie, à Hawaï, et dans le sud-est du pays du Texas à la Floride et à la Caroline du Nord[4].
Selon Catalogue of Life (25 juillet 2017)[5]
Selon Tropicos (25 juillet 2017)[1] (Attention liste brute contenant possiblement des synonymes) :
Panicum repens est une graminée fourragère appréciée dans un certain nombre de pays tropicaux asiatiques, qui permet de nourrir le bétail dans les régions rizicoles, en particulier les animaux de trait. La plante est également récoltée à la main sur les bords des routes et des rizières pour nourrir les bovins laitiers. En Irak, c'est une plante de pâturage importante pour les buffles des marais[6].
L'utilisation de cette graminée est recommandée aux États-Unis pour stabiliser les rives de cours d'eau. C'est une plante qui peut être utilisée dans des zones qui subissent des périodes d'inondation et de sécheresse[7].
Panicum repens, le panic rampant ou millet rampant, est une espèce de plantes monocotylédones de la famille des Poaceae (graminées), sous-famille des Panicoideae, originaire des régions tropicales et subtropicales de l'Ancien Monde.
Ce sont des plantes herbacées vivaces, aux rhizomes allongés, aux tiges (chaumes) dressées ou géniculées ascendantes, longues de 30 à 100 cm. Ces plantes qui poussent dans les zones humides, au bord des cours d'eau, se sont répandues dans toutes les régions tropicales et subtropicales du Monde.
Ce sont des adventices envahissantes, difficiles à éradiquer dès lors qu'elles se sont établies.
Panicum repens adalah spesies tumbuhan yang tergolong ke dalam famili Poaceae. Spesies ini juga merupakan bagian dari ordo Poales. Spesies Panicum repens sendiri merupakan bagian dari genus Panicum.[1] Nama ilmiah dari spesies ini pertama kali diterbitkan oleh L..
Panicum repens adalah spesies tumbuhan yang tergolong ke dalam famili Poaceae. Spesies ini juga merupakan bagian dari ordo Poales. Spesies Panicum repens sendiri merupakan bagian dari genus Panicum. Nama ilmiah dari spesies ini pertama kali diterbitkan oleh L..
Panicum repens é uma espécie de planta com flor pertencente à família Poaceae.
A autoridade científica da espécie é L., tendo sido publicada em Species Plantarum, Editio Secunda 1: 87. 1762.[1]
O seu nome comum é escalracho.[2]
É uma espécie vegetal muito resistente e com propriedades que a tornam indicada para jardins ou zonas públicas em que não é possível realizar um trabalho de manutenção muito cuidado.
Tem um crescimento acentuado nos meses mais quentes e que pode ser potencializado com a rega, alastrando rapidamente e com uma boa capacidade de enchimento das zonas a cobrir. Desenvolve-se através de guias das próprias folhas que nos nós criam raízes que rapidamente crescem e que fixam a planta ao solo. Nos meses mais frios entra como que em hibernação, crescendo pouco mas mantendo habitualmente a cor verde. Nos meses mais quentes em que haja falta de rega tem tendência a secar e a desenvolver-se menos, mas quando é regado de novo recupera rapidamente.
O seu grande crescimento em certas alturas do ano exige um corte regular para se manter agradável e controlado. A sua plantação é feita com o enterrar de pequenas estacas deste tipo de relva no solo, normalmente a uma distância sempre regular para facilitar o crescimento e uniformizar o aspecto do tapete. É fundamental regar bastante nos primeiros dias após a plantação para garantir a pega.
Trata-se de uma espécie presente no território português, nomeadamente em Portugal Continental, no Arquipélago dos Açores e no Arquipélago da Madeira.
Em termos de naturalidade é nativa de Portugal Continental e no Arquipélago da Madeira e introduzida no Arquipélago dos Açores.
Não se encontra protegida por legislação portuguesa ou da Comunidade Europeia.
Panicum repens é uma espécie de planta com flor pertencente à família Poaceae.
A autoridade científica da espécie é L., tendo sido publicada em Species Plantarum, Editio Secunda 1: 87. 1762.
O seu nome comum é escalracho.
É uma espécie vegetal muito resistente e com propriedades que a tornam indicada para jardins ou zonas públicas em que não é possível realizar um trabalho de manutenção muito cuidado.
Tem um crescimento acentuado nos meses mais quentes e que pode ser potencializado com a rega, alastrando rapidamente e com uma boa capacidade de enchimento das zonas a cobrir. Desenvolve-se através de guias das próprias folhas que nos nós criam raízes que rapidamente crescem e que fixam a planta ao solo. Nos meses mais frios entra como que em hibernação, crescendo pouco mas mantendo habitualmente a cor verde. Nos meses mais quentes em que haja falta de rega tem tendência a secar e a desenvolver-se menos, mas quando é regado de novo recupera rapidamente.
O seu grande crescimento em certas alturas do ano exige um corte regular para se manter agradável e controlado. A sua plantação é feita com o enterrar de pequenas estacas deste tipo de relva no solo, normalmente a uma distância sempre regular para facilitar o crescimento e uniformizar o aspecto do tapete. É fundamental regar bastante nos primeiros dias após a plantação para garantir a pega.
Ця багаторічна трава поширюється через її великі розгалужені кореневища. Кореневища повзуть по землі або можуть плавати у воді. Вони можуть досягати в довжину 6 метрів і глибини ґрунту 7 метрів. Стебла до 100 см, прямостоячі або висхідні, голі. Листові пластинки прямостоячі, плоскі або згорнуті, 7–25 см завдовжки, шириною 2–8 мм, шкірясті, жорсткі, сизі. Волоть 2–25 см. Колоски 2–2.5 мм, еліптичні. Цвіте з (березень) з травня по жовтень.
Африка: Алжир; Єгипет; Лівія; Марокко; Туніс; Ефіопія; Судан; Кенія; Танзанія; Уганда; Камерун; Заїр; Кот-д'Івуар; Гана; Гвінея; Ліберія; Малі; Нігер; Нігерія; Сенегал; Сьєрра-Леоне; Малаві; Мозамбік; Замбія; Зімбабве; Ботсвана; Намібія; Південна Африка — Капській провінції, Квазулу-Наталь, Трансвааль; Свазіленд; Мадагаскар. Азія: Саудівська Аравія; Ємен; Кіпр; Ірак; Ізраїль; Йорданія; Ліван; Сирія; Туреччина; Китай [пд.-сх.]; Японія — острови Кюсю, Рюкю, Сікоку; Тайвань; Індія — Ассам, Біхар, Карнатака, Керала, Мадхья-Прадеш, Махараштра, Мегхалая, Орісса, Таміл Наду, Тріпура, Уттар-Прадеш, Західна Бенгалія, Непал; Шрі-Ланка; Індокитай; Таїланд; Індонезія; Малайзія; Філіппіни. Південна Європа: Албанія; Колишня Югославія; Греція [вкл. Крит]; Італія [вкл. Сардинія, Сицилія]; Франція [вкл. Корсика]; Португалія [вкл. Мадейра]; Гібралатар; Іспанія [вкл. Балеарські острови, Канарські острови]. Натуралізований в деяких інших країнах. Росте на луках на піщаних, вологих ґрунтах.
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Це незавершена стаття про Тонконогові.Panicum repens là một loài thực vật có hoa trong họ Hòa thảo. Loài này được L. mô tả khoa học đầu tiên năm 1762.[1]
Panicum repens là một loài thực vật có hoa trong họ Hòa thảo. Loài này được L. mô tả khoa học đầu tiên năm 1762.
铺地黍（学名：Panicum repens）为禾本科黍属下的一个种。
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这是一篇與植物相關的小作品。你可以通过编辑或修订扩充其内容。 
ハイキビ Panicum repens L. は、イネ科の雑草の一つ。日本本土では分布の少ない海岸性の植物である。世界的にはたちの悪い雑草としてよく知られる。
ハイキビはキビ属植物の一つ。地下によく発達した地下茎を走らせる。葉をつける茎は上向きに伸びて、先端にまばらな花序を着ける。それほど背丈は高くならないが、地下茎でよく広がる。
日本本土では南岸沿いの僅かな地域に生息するのみで、いずれも海岸の湿った地に生育する野草である。だが世界的には熱帯から亜熱帯域に広く分布し、あちこちでやっかいな雑草として知られる。日本でも沖縄では広く畑作の雑草であり、特にサトウキビ畑で被害が大きい。また侵略的移入種として在来の生態系に及ぼす影響も大きいものとされる。
英名を Torpedograss （魚雷の草）と言う。これは地下茎先端が鋭く尖っており、魚雷を思わせるためである[1][2]。
地下茎が発達した多年生の草本[3]。匍匐茎は長く地下を這い、時には数mにも達する。その所々に丸く肥厚した節が数個数珠状に繋がる。地下茎の節からは直立する茎を単独に生じて、高さは40-100cm、淡緑色で滑らか、ややつやがある。
直立する茎はほとんど分枝せず、その節ごとに葉をつけるが、直立茎の下方では葉は葉鞘のみで葉身が発達せず、葉身は上の方にだけ出る。葉身は長さ8-20cm、幅は5-8mmで、葉の表面にまばらに短い毛がある。葉鞘は縁にだけ毛があり、葉舌は高さ0.3mm,で縁に１列の毛がある。
花期は9月から10月で、茎の先端から出る円錐花序は直立して生じ、高さ15-25cm、側枝は花の時期にはやや開くが、その前後にはほぼ上向きに伸びる。枝はややざらつき、まばらに小穂をつける。小穂は長楕円形で先端は尖る[4]。長さ2.5mmで、淡緑色だが時に淡く紫が乗る。第一包穎は長さが小穂の1/5-1/4で、鈍い三角形、小穂の基部を大きく取り巻く。第二包穎は紙質で七脈を持ち、小穂と同長。第一小花の護穎は第二包穎とほぼ同じ。第二小花の護穎は小穂の長さの3/4、革質で平滑で白く光沢がある。その縁は内側にある同質の内穎を抱える。
なお、花期については世界的には特に決まっておらず、日長と花芽形成との関係では中性植物、つまり生育期間であればいつでも花を作れる[5]。
花序
同・和歌山県南部
地下茎の様子
日本では四国南部、九州南部から琉球列島に分布する。ただし一般の図鑑に記述がないが、本州でも紀伊半島南部から若干の記録がある。四国での分布も四カ所に過ぎない[6]。
藤井(2007)はまた日本における南方系の植物の分布について論じ、本州南岸から南西諸島と伊豆小笠原の両側に分布が伸びるものと南西諸島側にのみ伸びるものがあると言い、後者には太平洋側に伸びるタイプと日本海側を北上するものがあるという。本種のそれは太平洋岸を東進・北上するタイプと述べている。同様に紀伊半島を北限とするものとしてシマサルナシやシマユキカズラ、ハカマカズラ等をあげ、これらの分布に最近新しい発見があることについては絶滅危惧種調査が盛んになったことで調査が行き届くようになったためと推察している。
世界的には世界中の熱帯から暖帯に広く分布しているものである。タイプ標本はヨーロッパ産であるが、広い地域にわたって移入されたと考えられており、その起源については不明である。北アメリカでの分布については古くには在来とする判断もあったが、旧熱帯から導入されたものとの見解もあり、判断が分かれる。ただ、北アメリカ南部において、この種が侵略的傾向が強いことは認められる。他に北アフリカ、地中海周辺地域、オーストラリア、アジアから知られる[7]。北アメリカでもっとも古い標本は1876年のものである。フロリダでは1932年がもっとも古い記録である[8]。
その分布の高緯度方向および高標高方向の限界は、寒冷な季節の長さによる[9]。
日本本土における生育環境は海岸の砂浜である。本州の産地である那智勝浦町のそれも砂浜であり、コウボウシバ、チガヤ、コマツヨイグサと混生し、部分的に純群落となっていた由[10]。九州ではたとえば垂水市や有明町では河口域や海岸の塩性湿地にハイキビ群落が優占し、大隅半島でも類似の環境に見られるとのこと[11]。
沖縄においてはハイキビは県内全域において山野、原野、農耕地に広く発生し、農地の雑草としても重視される[12]。ただ、海岸に多いのも確かで、たとえば慶佐次川ではマングローブ周辺のサワスズメノヒエ群落の近辺でハイキビが優占することがある旨の記述がある[13]。
世界的に見ると、その生育環境の範囲はかなり広い。Langeland et al.(1998)はこの種の生育環境について「湿気があるか水を含んだ砂地や有機物に富む土壌に生育するが、乾燥した高い土地にも生育する。（中略）出現する場所としては湿気のある砂浜や礁湖の海岸線、砂丘の上に広がり、砂丘の中の湿地、湖沼の水際、水路や溝、干潟や水面」と書き、いずれにせよ湿った環境に関わってもっとも頻繁に見られるとする[14]
なお、この植物は他感作用を有する可能性がある。室内実験で幾つかの植物の種子発芽を阻害するとの結果が得られている[15]。
また、この種はある程度の塩分耐性を持ち、海水の塩分濃度の半分程度で成長は大きく制限されるが、低濃度の場合、塩分がない場合より良く成長するとの実験結果もある[16]。
砂浜の群落(以下、すべてハワイ）
砂浜の群落・刈り取り中
池の周囲に繁茂する様子
小川沿いに生育する様子
この種は多年生で地下茎が発達するので、それによる無性生殖が盛んで、同時に穂を出して花をつける。しかし、地下茎による無性生殖が広範囲に見られるのに対して、種子形成による有性生殖はかなり限定的であるらしい。
沖縄本島周辺においては、奥村他(2002)は種子による繁殖は行われていないらしいと判断している。それによると、この地域で得られたものでは小穂に含まれる小花の中で、正常な構造を有したものは13%に過ぎず、それ以外のものでは構造の退化や萎縮などが見られ、また正常な小花ではそうでないものより柱頭や子房が小さい傾向があった。また、花粉では調査した全てが不稔であった由。
これは日本に限った話ではなく[17]、台湾においても有効な種子が観察されず、ジャワでは種子そのものが発見されなかった報告がある。北アメリカでも種子の発芽が確認できなかった事例などがあり、有性生殖が極めて限定的にしか行われていない事が考えられる。ただし種子形成が確認された例もあり、少数ながら有性生殖が行われていることもまた確かのようである。
日本本土では南方系の希少種であり、学問上重要なものと見なされている。高知県で絶滅危惧I類、大分県で準絶滅危惧種に指定されており、他に愛媛県で情報不足のカテゴリーで取り上げられている。
それ以南では多くの地域で雑草である。それでも世界の一部地域では在来野草として、飼料に利用される例もある[18]。アメリカでも当初は牛の飼料に使われたこともあるが、栄養的には他の牧草より劣っていることが後に示された。また、海岸水辺の砂を安定させ、あるいは水の多い時期に水田周辺の泥を安定確保する効果がある[19]。
沖縄県においては畑地の雑草として重要である。特にサトウキビ畑での被害が大きい。これについては後述する。
北アメリカでは、たとえばゴルフコースの芝生を荒らす雑草として嫌われる。この種が侵入するとバミューダグラス（ギョウギシバ属）の生産を2年で40%も減少させる。この種は温暖な地域で芝生に使われる除草剤の大部分に抵抗性を示す。この種を枯草剤グリホサートで管理することについていくつもの報告が出ている[20]。
また、侵略的移入種として、生態系に大きな影響を及ぼす点でも注目されている。
沖縄ではハイキビはサトウキビ畑の重要な雑草である[21]。実験的にはサトウキビの初期生育においてハイキビを除去しなかった場合、サトウキビの草丈の成長、葉数、地下根群等の量が大きく抑制され、分けつ茎の茎数では最大で80%もの減少となった。ハイキビは地下茎がよく発達するのが一つの特徴であるが、サトウキビ畑では約8割が地下20cmまでに集中するものの、40cmの層でも5.5%の存在があった。またトラクターで耕起砕土した場合も二節ないし三節を含む断片となるに過ぎず、それらは発芽して新たな増殖源となる。その発芽も地下40cmまでは可能である。つまり、トラクターや鍬で耕しても根茎を取り去ることは不可能であること、さらに重機ユンボ等を用いて70cmまで掘り返したとしても、最下層にあるものが上層に出て発芽する可能性が高いことなどをあげて、この植物を除去することの困難さを指摘している。
また、土地改良や造園事業においては、この種の地下茎の混入した畑土を移動させることでこの種の被害を広げる結果となっている。
北アメリカ南部では、本種は水際の生態系においてもっとも広範囲に進出している外来種の一つ[22]といった評価があり、その管理が問題となっている。例えばフロリダのオキーチョビー湖では数千ヘクタールもの水際とそれに接する水面や近隣区域の在来植生がこの種によって置き換えられている。結果としてスポーツフィッシングについてはそれに好適な条件の場所を大きく減少させ、またその水中での酸素を減少させることでも悪影響を与えている[23]。
この種の増殖を抑えるのは機械的方法でも化学的方法でも難しく、生物的な方法も見るべきものが見つかっていない。多くの節足動物がその群落に発見されるが特異的なものがいない。それに、他の作物に被害を与えるカメムシ目などの昆虫が多く生息しており、その面でも問題となりうる[24]。
ハイキビ Panicum repens L. は、イネ科の雑草の一つ。日本本土では分布の少ない海岸性の植物である。世界的にはたちの悪い雑草としてよく知られる。
