Panicum repens
| Panicum repens | |
|---|---|
| |
Scientific classification
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Clade: | Commelinids |
| Order: | Poales |
| Family: | Poaceae |
| Subfamily: | Panicoideae |
| Genus: | Panicum |
| Species: | P. repens
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| Binomial name | |
| Panicum repens | |
Panicum repensis a species ofgrassknown by many common names, includingtorpedo grass,creeping panic,panic rampant,couch panicum,wainaku grass,quack grass,dog-tooth grass,andbullet 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 theMediterranean,Israel,andArgentina.[6]It is present in many places as anintroduced speciesand often anoxious weed.It has been called "one of the world's worst weeds."[3]
Overview
[edit]This perennial grass spreads via its large, branchingrhizomes,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. Theinflorescenceis a loosepanicleof branches bearing small spikelets 2 to 3 mm (0.079 to 0.118 in) long.[6][7]
Habitat
[edit]This grass grows throughout the world in tropical and subtropical areas. It was introduced to the United States in seed forforagegrasses and probably inballastwater from ships. It was also imported by theUnited States Department of Agricultureto grow as a forage grass for cattle. It was deliberately planted throughout SouthFloridaand 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]InLake Okeechobee,it has invaded more than 16,000 acres ofmarsh.[6]It displaces native plants,[8]growing colonially in thick, monotypic stands.[3]Dense mats or stands of the grass causehypoxiain 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 anddunes,from Florida toTexas,where it occurs with beach plants such asturtleweed(Batis maritima),saltgrass(Distichlis spicata),marsh fimbry(Fimbristylis castanea),largeleaf pennywort(Hydrocotyle bonariensis), anddwarf saltwort(Salicornia bigelovii). It grows on manybarrier islands.It grows in many types ofwetlandhabitat, in and out of the water. It grows in freshwater marshes,salt marshes,mud flats,wetprairies,tide pools,bogs,and lakesides. It also invades drier habitat, such as coastal pine forests andwhite sand scrub.It easily moves into disturbed and cultivated areas such asditchesand canals.[6]It is a nuisance insodproduction.[1]InHawaii,it is a weed ofsugarcane(Saccharum officinarum).[3][5]In other areas, it can be found inturfandorchards.[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]
Propagation
[edit]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 producetillers.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 afterherbicideapplication, 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.Seedsare sometimes observed but they are apparently rarely viable, with many studies describing zerogermination.[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 intohay.However, it is not one of the morepalatableor nutritious grasses. It is also good forerosioncontrol because it binds the soil. Indeed, it is still recommended for planting along shorelines to stabilize them.[11]
References
[edit]- ^abcPanicum repens.University of Florida Center for Aquatic and Invasive Plants.
- ^Panicum repens.Smithsonian Marine Station at Fort Pierce.
- ^abcdeByrd, J. D. and V. Maddox.Torpedograss (Panicum repensL.)Mississippi State University Extension.
- ^Torpedograss.Texas A&M AgriLife Extension.
- ^abcHossain, M. A., et al. (1999).Effect of burial depth on emergence ofPanicum repens.Weed Science47(6) 651-56.
- ^abcdefghijStone, Katharine R. 2011.Panicum repens.In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory.
- ^abPanicum repens.Archived2016-03-04 at theWayback MachineGrass Manual Treatment.
- ^Smith, B., et al. (1993).Factors influencing the efficacy of glyphosate on torpedograss (Panicum repensL.).J Aquat Plant Manage31 199–202.
- ^abStephenson, D. O., et al. (2006).Control of torpedograss (Panicum repens) with trifloxysulfuron-sodium in bermudagrass (Cynodon dactylonxCynodon transvaalensis) turf.Weed Technology20(2) 351-55.
- ^Busey, P. (2003).Reduction of torpedograss (Panicum repens) canopy and rhizomes by quinclorac split applications.Weed Technology17(1) 190-94.
- ^TorpedograssPanicum repensL.USDA NRCS Plant Guide.
External links
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