Torpedo grass, Panicum repens, is a hardy perennial grass occurring widely throughout Florida but not native to North America. Shoots, up to 1 m tall, arise from sturdy, creeping or floating rhizomes. The rhizomes are pointed with torpedo-like growing tips. Aerial stems are rigid, erect to leaning, with lower portions often wrapped in bladeless sheaths. The upper leaf sheaths are mostly glabrous with hairs usually restricted to the upper margins. The ligule (thin outgrowth at the junction of the leaf and leafstalk) is a short-ciliate membrane. Leaf blades are narrow, linear, stiffly ascending to 25 cm long and 0.6 cm wide. The inflorescence is a loose open terminal panicle 7-22 cm long with with few to many branches and stakled spikelets that are 2-3 mm long and approximately 1 mm wide, with flower parts white with yellow. The small seeds are smooth and whitish (Langeland and Burks 1998, CAIP, ISSG).

General: Grass Family (Poaceae). It is a warm season, rhizomatous perennial, which may form extensive colonies. The rhizomes have characteristic torpedo-like apexes, hence the common name torpedo grass. The culms are erect, glabrous, and rigid and range in height from 12 to 31 inches. The sheaths are glabrous or pubescent with thin and dry margins. The leaf blades are mostly short, flat, or rolled in tightly. If flat, the blades are approximately ¹∕8 inch wide and if folded, the blades are approximately ¼ inch wide. The ligules are membranous with fringed hair surrounding them. The panicles are open, loose, 4 to 7 inches long, and with strongly ascending branches. The spikelets are straw colored and ¹∕16 inch long. The first glume is short and truncate. The second glume and sterile lemma are about equal in size and apically acute to acuminate with 7 to 9 weak nerves. The sterile pale is thin and dry. The fertile lemma and palea are straw colored and sharply angled. The caryopsis is pale yellow and oval in shape.

Bullet grass, bullet grass, coastal bermuda grass, couch panicum, creeping panic, dogtooth grass, panic rampant, quack grass, torpedo grass, wainaku grass. A synonym of torpedo grass is Panicum gouinii.

Panicum repens is a tufted perennial grass commonly seen in Western Ghats. In India, it is widely spreaded in almost all the districts in Andra Pradesh, Assam, Bihar, Karnataka, Kerala, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Sikkim, Tamil Nadu, Tripura and West Bengal (Cook 1996).

Panicum repens L.:
Argentina (South America)
Belize (Mesoamerica)
Brazil (South America)
Ethiopia (Africa & Madagascar)
Cameroon (Africa & Madagascar)
South Africa (Africa & Madagascar)
United States (North America)
Gabon (Africa & Madagascar)
Madagascar (Africa & Madagascar)
Nicaragua (Mesoamerica)
Honduras (Mesoamerica)
Spain (Europe)
Tanzania (Africa & Madagascar)
Uganda (Africa & Madagascar)
Kenya (Africa & Madagascar)
Guyana (South America)
Uruguay (South America)
Caribbean (Caribbean)
Mexico (Mesoamerica)
India (Asia)
Bolivia (South America)
China (Asia)

Panicum littorale Sosef:
Gabon (Africa & Madagascar)

Panicum gouinii var. pumilum E. Fourn.:
Mexico (Mesoamerica)

Panicum gouinii var. pumilum E. Fourn.:
Mexico (Mesoamerica)

Panicum ischaemoides Retz.:
Brazil (South America)

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

Believed native to Europe or Australia Panicum repens is now widely distributed throughout the tropics and subtropics from approximately 43° North latitude to 35° South latitude (Holm et al. 1977).In the U.S. southeast, the plant can be found from Florida to the Gulf coast of Texas, and northward along the Atlantic Coast to North Carolina. The species has also been introduced to California and Hawaii, where it has become a pest plant to the sugarcane industry (Holm et al. 1977, Godfrey and Wooten 1979, Small 1933, Langeland and Burks 1998). By 1995 P. repens was reported as naturalized in 75% of Florida counties (Wunderlin and Hansen 2004). As of April, 2007, the Florida Exotic Pest Plant Council (FLEPPC) reports the species as present in 57 of 67 Florida counties. Panicum repens occurs along the entire east coast of Florida, including the six India River Lagoon watershed counties.

Pantropic. Taiwan, common in sunny to slightly shaded, moist places.

Tropical & subtropical areas of Old & New Worlds.

Torpedo grass is found in marshy shores along the Gulf Coast from Florida to Texas and along tropical and subtropical coasts around the world. It is also found in disturbed sites, canals, and in poorly drained soil. It is possibly introduced to Louisiana and the United States. Linneaus in Europe first described torpedo grass in 1762. It was first collected in North America near Mobile, Alabama in 1876. For current distribution, consult the Plant Profile page for this species on the PLANTS Web site.

Perennials; culm erect or decumbent, 20-50 cm tall, nodes brownish black. Blade 8-20 cm long. Sheath glabrous. Ligule membranaceous, truncate, ca. 1 mm long, fringed with haris, Panicle open, 5-15cm long, terminal and axillary. Spikelets glabrous, acute at length of spikelet. Upper glume and lower lemma equal, strongly 9-11-veined. Lower palea membranaceous, nearly as long as spikelet. Upper lemma smooth, shiny, brown at maturity, coriaceous.

Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stolons or runners present, Stems nodes swollen or brittle, Stems erect or ascending, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems tere te, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem nodes bearded or hairy, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath hairy at summit, throat, or collar, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades more or less hairy, Leaf blades scabrous, roughened, or wrinkled, Ligule present, Ligule an unfringed eciliate membrane, Ligule a fringed, ciliate, or lobed membrane, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence a contracted panicle, narrow ly paniculate, branches appressed or ascending, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Spikelets pedicellate, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 florets, Spikelet with 1 fertile floret and 1-2 sterile florets, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating below the glumes, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes distinctly unequal, Glumes equal to or longer than adjacent lemma, Glume equal to or longer than spikelet, Glumes 1 nerved, Glumes 4-7 nerved, Glumes 8-15 nerved, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma glabrous, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins inrolled, tightly covering palea and cary opsis, Lemma straight, Palea present, well developed, Palea about equal to lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis, Caryopsis ellipsoid, longitudinally grooved, hilum long-linear.

Perennial, rhizomatous. Culms tough, erect or decumbent, 30–125 cm tall. Leaves cauline; leaf sheaths glabrous, striate, puberulous to ciliate on margins, especially toward throat; leaf blades linear, flat or convolute, often stiff and pungent, markedly distichous, ascending close to the culm, 7–25 × 0.2–0.8 cm, apex acute or acuminate; ligule 0.5–1.5 mm, a ciliolate membrane. Panicle terminal, narrowly oblong in outline, 5–20 cm, sparsely to moderately branched; branches glabrous, scabrid, ascending. Spikelets ovate, 2.5–3 mm, acute; lower glume broadly ovate, 1/3 length of spikelet, hyaline, 1(–3)-veined, clasping at the base of the spikelet, obtuse or acute; upper glume ovate, as long as spikelet, membranous, 7–9-veined, acute; lower floret staminate, lemma similar to upper glume, palea well developed; upper floret almost as long as spikelet, pale yellow, shiny. Fl. and fr. Jun–Nov. 2n = 40.

100 m

Panicum repens is a perennial grass that grows to 1 m in height.

Holotype for Panicum littorale C. Mohr ex Vasey
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): C. Mohr
Year Collected: 1877
Locality: Mobile., Mobile, Alabama, United States, North America

Several Panicum congeners similar in appearance occur in Florida. Beachgrass (Panicum amarum), redtop panicum (P. rigidulum), and maidencane (P. hemitomon) all can be found within the IRL watershed counties). Details of the rhizomes, leaves, and inflorescence must be studied to distinguish among species.

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

Depth range based on 6 specimens in 1 taxon.

Environmental ranges
  Depth range (m): 1 - 1
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Moist places, marine habitats, streams. Fujian, Guangdong, Guangxi, Hainan, Jiangxi, Sichuan, Taiwan, Yunnan, Zhejiang [tropical and subtropical locations worldwide].

Adaptation: It may grow off shores and into water up to 6 feet deep forming a thick dense floating mat. Torpedo grass begins to grow in February and the seeds are formed in July. They cannot tolerate cold weather and will die after the first frost. The dry grass in winter retains a relatively high nutrient content. Once established, torpedo grass is difficult to eradicate. It can be distributed by using improper soil sanitation and by tilling and fertilizing. Torpedo grass is tolerant of drought and partial shade, and can grow on heavy upland soils. It thrives best on moist to wet sandy or organic soil.

Torpedo grass is propagated by seed or by plant division; however the best propagation method is through plant division. The seeds are variable in abundance and viability.

The rhizomes can be dug and cut into segments, which will then sprout new shoots. The stems may also be cut and propagated.

It is not recommended to mix torpedo grass seeds with cool season grass seeds. In parts of the United States where cool season grasses dominate, the warm season grasses can be taken over because they develop slower than the cool season grasses. It is also recommended that seed not be moved more than 300 miles north, 100 miles east or west, or 200 miles south of its point of origin.

Autotrophic (photosynthetic).

Panicum repens tends to produce dense monocultures capable of displacing native vegetation.Invasion History: The original native range of Panicum repens is in dispute. The type specimen from which the species was first described by Linnaeus in 1762 was collected from Spain, although several authorities suggest the native range of the species to be Australia. The first description of this species (as P. airoides) from Australia dates to 1810, therefore it is clear that the species has been historically present in both locations.P. repens was intentionally introduced to the southeastern United States in the late 19th century as a cattle forage grass (Tarver 1979). It was introduced to the Gulf Coast prior to 1876, at which time it was first collected outside of cultivation near Mobile, Alabama (Beal 1896; Yarlett 1996). The plant was cultivated in Florida from at least the 1920s to the 1950s, becoming common in the state during this time and planted in most southern Florida counties and also in some central and north-central counties by 1950 (Hodges and Jones 1950).Since this initial introduction P. repens has escaped cultivation to spread into natural and agricultural lands in Alabama, Florida, Louisiana, Mississippi, North Carolina, South Carolina, and Texas. The plant has also been introduced to California and Hawaii (USDA, NRCS 2004). Potential to Compete With Natives: The impressive vegetative reproductive capacity of Panicum repens allows it to quickly produce dense monocultures capable of displacing native vegetation, particularly in wetland and marginal habitats where the species thrives (Shilling and Haller 1989, Bodle and Hanlon 2001).Growth, vegetative reproduction, and spread of the species in agricultural areas are facilitated by tilling and fertilization (Hodges and Jones 1950, FLEPPC 2003). Possible Economic Consequences of Invasion: Sutton (1996) notes that worldwide Panicum repens is one of the most invasive exotic grasses of terrestrial, wetland and aquatic habitats of the tropics and subtropics. It is now listed as a Category I invasive species because of its ability to invade and alter native plant communities (FLEPPC 2005).In addition to overtaking natural areas, P. repens invades cultivated lands and displaces more desirable forage species. Although it was originally introduced for cattle forage, torpedograss becomes tough later in the growing season and is generally neglected by livestock. Additionally, P. repens may interfere with flood control, navigation, irrigation, recreation, and turf production (Shilling and Haller 1989, Willard et al. 1998). This invasive species has been a significant culprit in Florida citrus grove infestation and has also been reported from parks, golf courses, and preserves throughout Florida (Fleming et al. 1978, Baird et al. 1983, FLEPPC 1996).Limited management of P. repens in Florida (e.g., management in flood control systems) from 1980-1988 cost an average of $2-2.5 million per year (Schmitz et al. 1988, Schardt and Schmitz 1991).

Panicum repens is a marginal species that occurs in and around shallow water. It is found in more than 70% of Florida's public water bodies. The largest Florida P. repens infestation, nearly 6,000 ha, is the infestation occurring in and around Lake Okeechobee (Schardt 1994, Bodle and Hanlon 2001).

Panicum repens can reproduce sexually through flowering and seed production, though the principal means of propagation is reported to be rhizome extension and fragmentation (Holm et al. 1977).Small P. repens fragments can give rise to dense clonal stands through vegetative growth and rhizome fragments buried as deep as 50 cm can send up new shoots (Hossain et al. 1999, Brecke et al. 2001). The lack of apical dominance also allows each node the ability to produce axillary buds along entire rhizome lengths (Wilcut et al. 1988). Hossain et al. (2001a) reports that a single culm emerging from a single rhizome bud produced approximately 23,000 rhizome buds in a single year.

Populations are capable of flowering and producing seeds year-round, but seed abundance and viability are highly variable (Whyte et al. 1959, Peng and Twu 1979, Wilcut et al. 1988).

Collection Sites: world map showing specimen collection locations for Panicum repens

Barcode of Life Data Systems (BOLD) Stats
                                                             

Specimen Records:	2
Specimens with Sequences:	3
Specimens with Barcodes:	3
Public Records:	0
Species:	1
Species With Barcodes:	1

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 4
Species: 7
Species With Barcodes: 1

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: GNR - Not Yet Ranked

Consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values.

Population

Population Trend

Major Threats

Conservation Actions

Contact your local NRCS Field Office. Common seed and container plants are readily available from a number of growers, wholesalers, and retailers of native seed.

To maintain existing torpedo grass colonies, avoid long term deep flooding and abusive livestock grazing. The plant prospers with periodic fire provided sufficient soil moisture is present to avoid scorching root systems. Once established, it is difficult to kill. Check with the local extension service for recommended herbicides. Torpedo grass has no known pests or problems.

Livestock: It was once used for cattle in the 1920s and is resistant to grazing and trampling; however, better forages are now available that has higher quality and does not create the potential weed problems that torpedo grass did.

Wildlife: Waterfowl and songbirds regularly use torpedo grass. It is an excellent forage plant for several mammals.

Erosion Control: Torpedo grass is recommended for the use of shoreline stabilization. It may be used in

areas that have periods of both inundation as well as drought.

Conservation Practices: Torpedo grass, because of its growth habit, potentially has application when established with certain conservation practices; however, conservation practice standards vary by state. For localized information, consult your local NRCS Field Office.