Pacific Island Ecosystems at Risk (PIER)

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Hyparrhenia rufa
(Nees) Stapf, Poaceae
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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  Reject, score: 7 (Go to the risk assessment)

Common name(s): [more details]

English: giant thatching grass, jaragua grass, thatch grass, thatching grass

French: herbe rouge

Hindi: jaragua

Spanish: yaragua

Habit:  grass

Description:  "Perennial or sometimes annual [grass]; culms densely tufted, forming large clumps 3-25 dm tall, nodes long-pilose. Sheaths sparsely long-pilose, the hairs white, appressed at base, upper sheaths glabrous but with margins ciliate and hairs readily deciduous; ligule a firm, brownish membrane, 1-2.5 mm long; blades flat, glabrous or upper surface hirsute, 30-60 cm long, 2-8 mm wide, narrowed at base. Inflorescences large, paniculate, with numerous branches, the branches lax or contracted, fasciculate, 5-80 cm long, spathes linear-lanceolate, becoming reddish and rolled around the peduncle, 3-5 cm long, sparsely to densely long-pilose, racemes dull yellow, sometimes red-tinged, (1.5-)2-2.5 cm long, with (7-)9-14 awns per raceme pair, the awns rarely reflexed, with 1 homogamous pair of spikelets at the base of the lowest or of both racemes, raceme-bases unequal, sometimes connate, the upper one 2-3.5(-4) mm long, glabrous, rarely with a few long hairs, the articulation with the peduncle apex glabrous; sessile spikelet (3-)3.5-4.5(-5) mm long, glabrous to pubescent, but usually sparsely covered with stiff red hairs, usually glossy; pedicellate spikelet acute or rarely mucronate, callus 0.2-0.8 mm long, short and rounded to cuneate, narrowly truncate; lemma slender, filiform, ca. 2 mm long, membranous, awn arising from bifid apex, strongly twisted, geniculate, pubescent; ellipsoid to ovoid, ca. 3 mm long" (Wagner et al., 1999; p. 1554).

Description from GrassBase.

Habitat/ecology:  "Grassland, savanna, disturbed sites.  This grass occurs as a native in seasonally flooded grassland and open woodland.  It is a drought tolerant species and withstands dry seasons of several months, seasonal burning but also temporary flooding.  It forms dense swards where invasive that displace native grasses and forbs, preventing the establishment of other species and transforming native savannas into species-pure stands"  (Weber, 2003; p. 207).  Dry to mesic roadsides, disturbed areas. May carry wildfire.

"Grows in sandy or loamy soil.  Found on disturbed ground and roadsides." (Smith, 2002; p. 75). In Fiji, "reported as escaped and naturalized, but apparently it is uncommon" (Smith, 1979; pp. 380-381). In Hawai‘i, "naturalized and common along roadsides and in cultivated fields, 10-660 m" (Wagner et al., 1999; p. 1554).

Propagation:  "Seeds are dispersed by wind.  Spread is also by vehicles and machinery, e.g. road graders." (Smith, 2002; p. 75).

Native range:  Tropical and southern Africa; cultivated and naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Fiji
Fiji Islands
Fiji Islands introduced
invasive
Smith, Albert C. (1979) (pp. 380-381)
Not common. Vouchers cited: DA 3586, DA 3632, DA 7235, DA 8315.
Fiji
Fiji Islands
Viti Levu Island   Bishop Museum (Honolulu) (1952) (voucher ID: BISH 31695)
Taxon name on voucher: Hyparrhenia rufa (Nees) Stapf
French Polynesia
Society Islands
Raiatea (Havai) Island introduced
invasive
Welsh, S. L. (1998) (p. 338)
Vouchers cited: Florence 4620, BRY 25740, BRY 26371
French Polynesia
Society Islands
Raiatea (Havai) Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Voucher cited: J. Florence 3388 (PAP)
Adventice
French Polynesia
Society Islands
Raiatea (Havai) Island   Bishop Museum (Honolulu) (1982) (voucher ID: BISH 492124)
Taxon name on voucher: Hyparrhenia rufa (Nees) Stapf
French Polynesia
Society Islands
Raiatea (Havai) Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 38269)
Taxon name on voucher: Hyparrhenia rufa
French Polynesia
Society Islands
Tahiti Island introduced
invasive
Welsh, S. L. (1998) (p. 338)
Voucher cited: Florence 3388
French Polynesia
Society Islands
Tahiti Island introduced
invasive
Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013)
Vouchers cited: J. Florence 4620 (PAP), W.A. Whistler & M. Guérin 23 (PAP)
Adventice
French Polynesia
Society Islands
Tahiti Island   Bishop Museum (Honolulu) (1983) (voucher ID: BISH 554433)
Taxon name on voucher: Hyparrhenia rufa (Nees) Stapf
French Polynesia
Society Islands
Tahiti Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 38310)
Taxon name on voucher: Hyparrhenia rufa
Guam
Guam Island
Guam Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1987) (p. 44)
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1554)
Voucher cited: Judd s. n. (BISH)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1554)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1554)
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1554)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1554)
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
invasive
Smith, Nicholas M. (2002) (p. 75)
Australia
Australia (continental)
Queensland introduced
invasive
Smith, Nicholas M. (2002) (p. 75)
China
China
China (People's Republic of) introduced
cultivated
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Colombia
Colombia
Colombia (Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 187-188)
Costa Rica
Costa Rica
Costa Rica (Republic of) introduced
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 187-188)
Guatemala
Guatemala
Guatemala (Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 187-188)
Honduras
Honduras
Honduras (Republic of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 187-188)
Thailand
Thailand
Thailand (Kingdom of)   Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (pp. 187-188)
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
La Réunion (France)
La Réunion Island
La Réunion Island uncertain if native
Lavergne, Christophe (2006)
"Weed (indigène?)"
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island introduced
invasive
cultivated
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Naturalized
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)
USA (Florida) introduced
U.S. Dept. Agr., Agr. Res. Serv. (2013)

Comments:  A serious weed in Colombia (Smith, 2002; p. 75). An aggressive weed in Costa Rica.

Control: 

Physical:  "Cutting before seeds ripen prevents seed dispersal"  (Weber, 2003; p. 207).

Additional information:
Report (PDF format) from US Geological Survey, Biological Resources Division, Haleakala Field Station, Hawaii "Plants of Hawaii".

Additional online information about Hyparrhenia rufa is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Hyparrhenia rufa as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Hyparrhenia rufa may be available from the Germplasm Resources Information Network (GRIN).

References:

Bishop Museum (Honolulu). 1952. Voucher specimen #BISH 31695 (Parham, B.E. 3632).

Bishop Museum (Honolulu). 1982. Voucher specimen #BISH 492124 (Florence, J. 3388).

Bishop Museum (Honolulu). 1983. Voucher specimen #BISH 554433 (Florence, J. 4620).

Cronk, Q. C. B./Fuller, J. L. 2001. Plant invaders. Earthscan Publications, Ltd., London. 241 pp.

Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. 2013. Base de données botaniques Nadeaud de l'Herbier de la Polynésie Française (PAP). (online resource).

Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce. 1987. A geographical checklist of the Micronesian monocotyledonae. Micronesica 20:1-126.

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Lavergne, Christophe. 2006. List des especes exotiques envahissantes a La Reunion. Unpublished manuscript (Excel file). .

Smith, Albert C. 1979. Flora Vitiensis nova: a new flora of Fiji. National Tropical Botanical Garden, Lawai, Kauai, Hawaii. Volume 1. 494 pp.

Smith, Nicholas M. 2002. Weeds of the wet/dry tropics of Australia - a field guide. Environment Centre NT, Inc. 112 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2013. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

Welsh, S. L. 1998. Flora Societensis: A summary revision of the flowering plants of the Society Islands. E.P.S. Inc., Orem, Utah. 420 pp.


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This page was created on 1 JAN 1999 and was last updated on 11 MAY 2013.