(Kunth) Hitchc., Poaceae |
|
Present on Pacific Islands? no
Primarily a threat at high elevations? no
Risk assessment results:
Australia: Reject, score: 13 (Go to the risk assessment)
Risk assessment of Echinochloa polystachya from the Government of Queensland, Australia (PDF format).
Other Latin names: Echinochloa spectabilis (Nees ex Trin.) Link; Oplismenus polystachyus Kunth.; Panicum polystachyum (Kunth) Steud.; Panicum spectabile Nees ex Trin.
Common name(s): [more details]
English: aleman grass, creeping rivergrass |
Spanish: paja pelua, pasto chiguirera |
Habit: grass
Description: "Culms coarse to 2 m high in flower, from a long creeping and rooting base, glabrous, except the nodes hispid with dense yellowish hairs; leaf-blades up to 2.5 cm broad, scabrid; racemes ascending, 3-6 cm long, densely hispid at the base; spikelets nearly sessile, plano-convex, about 5 mm long." (Adams, 1972)An aquatic or semi-aquatic, perennial, stoloniferous grass. Leaves flat, smooth, 20-60 cm long and 1-1.5 cm wide (Csurhes and Edwards, 1998; pp. 156-157).
"Perennial grass with hygro habits, up to 3 m height, with decumbent culms, simple, cylindrical, with long internodes semi-glabrous, roots fasciculated, adventitious rooting may also be observed, leaves of somewhat red-purplish colour, limbs plains, long and acuminated" (Ecoport).
Description from GrassBase.
Habitat/ecology: "Freshwater wetlands, riparian habitats. A C4 aquatic grass of floodplains and estuaries with a very high productivity. The grass does not tolerate drought and frosts, and grows well in standing water. It is adapted to wet and very wet soils, and to varying water levels. The fast growing grass forms extensive monotypic stands on the lower levels of floodplains, crowding out native water plants and altering the vegetation structure. It grows rapidly during floods and decays rapidly during water retreat, resulting in a high release of nutrients during the low water period. This nutrient flush may affect water quality and reduce the oxygen content" (Weber, 2003; p. 143).
"Spread vegetatively when pieces of stems and roots are distributed by floodwaters. Seed production in Australia is generally thought to be poor." (Smith, 2002; p. 73).
Propagation: "Spread vegetatively when pieces of stems and roots are distributed by floodwaters. Seed production in Australia is generally thought to be poor." (Smith, 2002; p. 73).
Native range: "A native of tropical and subtropical countries of America from southern USA to northern Argentina where it forms dense swards in seasonal swamps and on less wet ground" (Smith, 2002; p. 73).
Presence:
Pacific Rim | |||
Country/Terr./St. & Island group |
Location |
Cited status &
Cited as invasive & Cited as cultivated & Cited as aboriginal introduction? |
Reference &
Comments |
Australia
Australia (continental) |
Northern Territory |
introduced
cultivated |
Csurhes, S./Edwards, R. (1998) (pp. 156-157) |
Australia
Australia (continental) |
Northern Territory |
introduced
invasive cultivated |
Smith, Nicholas M. (2002) (p. 73)
Established as a weed on the Mary River. |
Australia
Australia (continental) |
Queensland |
introduced
invasive cultivated |
Csurhes, S./Edwards, R. (1998) (pp. 156-157) |
Central America
Central America (Pacific rim) |
Costa Rica (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Central America
Central America (Pacific rim) |
Honduras (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Central America
Central America (Pacific rim) |
Nicaragua (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Central America
Central America (Pacific rim) |
Panama (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Mexico
Mexico |
Mexico (United Mexican States) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
South America (Pacific rim)
South America (Pacific rim) |
Chile (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
South America (Pacific rim)
South America (Pacific rim) |
Ecuador (Republic of) (continental) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
South America (Pacific rim)
South America (Pacific rim) |
Perú (Republic of) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Also reported from | |||
Country/Terr./St. & Island group |
Location |
Cited status &
Cited as invasive & Cited as cultivated & Cited as aboriginal introduction? |
Reference &
Comments |
United States (continental except west coast)
United States (other states) |
United States (other states) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Louisiana, Texas |
United States (continental except west coast)
United States (other states) |
USA (Florida) |
native
|
U.S. Dept. Agr., Agr. Res. Serv. (2013) |
Comments: A serious weed in Queensland, Australia (Smith, 2002; p. 73). Considered a high priority threat to northern Australia (Csurhes and Edwards, 1998; pp. 156-157).
Control: "Scattered plants may be removed manually, larger stands treated with herbicide" (Weber, 2003; p. 143).