Pacific Island Ecosystems at Risk (PIER)

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Sporobolus pyramidatus
(Lam.) Hitchc., Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 14 (Go to the risk assessment).

Common name(s): [more details]

English: giant rat's tail grass, whorled dropseed

Habit:  grass

Description:  "Low, tufted perennial.  Culms numerous, often spreading at base, glabrous, mostly 10-50 cm tall.  Sheaths glabrous or with a few hairs on the upper margins.  Ligule a fringe of hairs on a membranous collar, 0.5-0.8 mm long.  Blades flat, 3-12 (-20) cm long and mostly 2-4 mm broad, usually ciliate on lower margins and sparsely hispid on adaxial surface.  Panicles open, more or less pyramidal, mostly 3-15 (-18) cm long and 2-5 cm broad at base, the lower and middle branches in whorls and bare of spikelets on the lower 1/3-1/2.  Spikelets 1.5-2.0 mm long, the lateral ones on very short pedicels.  Glumes very unequal, thin, acute, the first 0.3-0.8 mm long, the second as long as the lemma.  Lemma acute, glabrous or scabrous.  Palea hyaline, slightly shorter than the lemma.  Grain broadly oblong, flattened laterally, usually 0.6-0.9 mm long, pale orange, the pericarp finely striate" (Howard, 1979; pp. 73-74).

Description from GrassBase.

Habitat/ecology:  "Frequent on coastal sands and inland on low, saline or alkaline sites" (Howard, 1979; pp. 73-74).  In Hawai‘i, "adventive in coastal sites" (Wagner et al., 1999; p. 1596). "In open sandy or alkaline soil" (Wiggins & Porter, 1971; pp. 880-881).

Propagation:  "Mature seeds become sticky when damp and are dispersed when adhered to animal fur, clothes, vehicles and machinery.  Roadside slashing equipment seems to be responsible for much spread along roadsides in rural areas.  Also dispersed by water and as a contaminant of nay.  The thousands of seeds produced have a viability of up to 10 years.  Seeds rapidly, even if grazed or slashed."  (Smith, 2002; p. 77).

Native range:  "Kansas to Colorado [U.S.] and south through the West Indies and Mexico to Argentina" (Howard, 1979; pp. 73-74).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
State of Hawaii
Hawaiian Islands
French Frigate Shoals introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (pp. 24-25)
Voucher cited: Herbst 6232 (BISH)
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Snow, Neil/Lau, Alex (2010) (p. 56)
Voucher cited: C. Imada et al. 94-3 (BISH)
State of Hawaii
Hawaiian Islands
Kaho‘olawe Island introduced
invasive
Starr, Forest/Starr, Kim (2011) (p. 31)
Voucher cited: Starr, Starr & Hagashino 080210-01 (BISH)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wood, K. R. (2006) (p. 18)
Vouchers cited: K.R. Wood 10709 (BISH, PTBG, NY, US), K.R. Wood 10914 (PTBG)
State of Hawaii
Hawaiian Islands
Kure Atoll introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (pp. 24-25)
Voucher cited: Herbst 6271 (BISH)
State of Hawaii
Hawaiian Islands
Kure Atoll introduced
invasive
Starr, Forest/Martz, Kim/Loope, Lloyd (2001) (p. 17)
Common on runway margins and in open areas.
State of Hawaii
Hawaiian Islands
Laysan Island introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (pp. 24-25)
Voucher cited: McDermond & Niethammer s.n. (BISH)
State of Hawaii
Hawaiian Islands
Laysan Island introduced
invasive
Starr, Forest/Martz, Kim (1999) (p. 11)
Patches of this grass were seen on the south side of the lake on and near the guano hard pan.
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd L. (2006) (p. 40)
Voucher cited: Starr & Starr 050517-6 (BISH)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Wagner, Warren L./Herbst, Derral R. (1995) (pp. 24-25)
Vouchers cited: Whitney 4040 (BISH), Stone 1243 (BISH), Herbst 1367 (BISH), Herbst & Walker 6086 (BISH), Herbst & Walker 6073 (BISH), Herbst 6159 (BISH)
State of Hawaii
Hawaiian Islands
Tern Island introduced
invasive
Starr, Forest/Martz, Kim (1999) (p. 7)
Dense near the edge of the runway and common further in vegetation.
Solomon Islands
Solomon Islands
Solomon Islands   Swarbrick, John T. (1997) (p. 97)
Solomon Islands
Solomon Islands
Solomon Islands native
Hancock, I. R./Henderson, C. P. (1988) (p. 110)
United States (other Pacific offshore islands)
Midway Atoll
Eastern Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd (2008) (pp. B-13)
Voucher cited: Starr & Starr 080605-02
United States (other Pacific offshore islands)
Midway Atoll
Sand Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd (2008) (pp. B-13)
Voucher cited: Starr & Starr 080602-01
United States (other Pacific offshore islands)
Midway Atoll
Spit Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd (2008) (pp. B-13)
Voucher cited: Starr & Starr 080603-01
United States (other Pacific offshore islands)
Midway Atoll
Spit Island introduced
invasive
Starr, Forest/Starr, Kim/Loope, Lloyd L. (2010) (p. 66)
Voucher cited: Starr & Starr 080603-01 (BISH)
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)
Queensland introduced
invasive
Smith, Nicholas M. (2002) (p. 77)
Chile (continental)
Chile
Chile (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Colombia
Colombia
Colombia (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Costa Rica
Costa Rica
Costa Rica (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
El Salvador
El Salvador
El Salvador (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Guatemala
Guatemala
Guatemala (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Honduras
Honduras
Honduras (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)
Nicaragua
Nicaragua
Nicaragua (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Panama
Panama
Panama (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Perú
Perú
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore
Singapore
Singapore (Republic of) introduced
invasive
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 81)
Sporobolus indicus (L.) R. Br. var. pyramidalis (P. Beauv.) Veldk., casual
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
British Indian Ocean Territory
Chagos Archipelago
Diego Garcia Island introduced
invasive
Rivers, Julie (2004) (p. 2)
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)


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This page was created on 1 JAN 1999 and was last updated on 30 DEC 2011.