Pacific Island Ecosystems at Risk (PIER)

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Amaranthus deflexus
L., Amaranthaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: Argentine amaranth, deflexed amaranth, large-fruit amaranth, low amaranth, perennial pigweed, prostrate amaranth, spreading amaranth, tow amaranth

Habit:  herb

Description:  "Plants short-lived perennial or annual, pubescent in distal parts of plant or becoming glabrescent at maturity. Stems ascending or prostrate, profusely branched basally, radiating from rootstock, mostly 0.2-0.5 m. Leaves: petiole 1/2 as long as to equaling blade; blade rhombic-ovate or ovate to lanceolate, 1-2 x 0.5-1 cm, base tapering or cuneate, margins entire, plane or slightly undulate, apex subacute, obtuse, or retuse or shallowly emarginate, mucronulate. Inflorescences terminal, erect, compact, pyramidal panicles and also some axillary clusters, green or silvery green, occasionally tinged with red, leafless at least distally. Bracts of pistillate flowers linear, 0.5-1 mm, 1/2 as long as tepals. Pistillate flowers: tepals 2-3, narrowly elliptic or oblanceolate, not clawed, equal or subequal, 1.2-2 mm, apex broadly acute; style branches erect; stigmas 3. Staminate flowers clustered at tips of inflorescences; tepals 2-3; stamens 2-3. Utricles marked with 2(-3) green lines that intersect at apex and divide fruit into halves or quarters, slightly to distinctly inflated, ellipsoid, 2-3 mm, distinctly longer than tepals, smooth (in dry plants wrinkled or rugose), indehiscent. Seeds very dark brown to black, 1-1.2 mm in diameter, shiny, filling only proximal portion of fruit"  (Flora of North America online).

Description from Flora of New Zealand.

Habitat/ecology:  In North America, "ballast heaps, railroads, other disturbed habitats; 0-500 m"  (Flora of North America online).  In New Zealand, "waste places, especially on shingle or gravel, particularly around settled areas"  (Webb et al., 1988; p. 104).

Propagation:  Seed

Native range:  Argentina, Bolivia (possibly), southern Peru; naturalized worldwide (GRIN).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Más a Tierra (Robinson Crusoe Island) introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 551)
Chile (offshore islands)
Juan Fernández Islands
Isla Más Afuera (Alejandro Selkirk Island) introduced
invasive
Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands)
Juan Fernández Islands
Isla Más Afuera (Alejandro Selkirk Island) introduced
invasive
Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 551)
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)
New South Wales introduced
invasive
National Herbarium of New South Wales (2013)
Naturalised
Japan
Japan
Japan (country) introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 182)
New Zealand
New Zealand
New Zealand (country) introduced
invasive
Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 104)
Perú
Perú
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast)
United States (west coast states)
USA (Oregon) introduced
Flora of North America Editorial Committee, eds. (2013)
United States (west coast)
United States (west coast states)
USA (California) introduced
Flora of North America Editorial Committee, eds. (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) introduced
U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
Ala., Fla., Ga., La., Mass., N.J., N.Y., Pa., Tenn., Va.


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 8 FEB 2011 and was last updated on 21 FEB 2013.