Andropogon bicornis L., Poaceae

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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 18 (Go to the risk assessment).

Common name(s): [more details]

English: West Indian foxtail grass

French: herbe panache

Spanish: barbas de indio, cola de caballo, cola de cabos, cola de venado, rabo de zorro, zacate cabezón, zacaton

Habit:  grass

Description:  "Habit: Perennial; caespitose. Culms erect; 150-250 cm long; 4-6 mm diam. Culm-internodes thick-walled. Culm-nodes glabrous. Lateral branches ample. Leaf-sheaths keeled. Ligule a ciliolate membrane; 1-1.2 mm long. Leaf-blades 25-50 cm long; 2-6 mm wide. Leaf-blade surface glabrous. Leaf-blade margins scabrous. Inflorescence: Synflorescence compound; paniculate (obovate); dense. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear; 3-4 cm long. Racemes 2; paired; 2.5-3.5 cm long. Rhachis fragile at the nodes; plumose on surface; plumose on margins. Rhachis hairs 6-8 mm long. Rhachis internodes filiform; 2.5-3 mm long. Rhachis internode tip transverse; cupuliform; with simple rim. Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 3-4 mm long; plumose; with 6-8 mm long hairs. Sterile spikelets: Companion sterile spikelets represented by barren pedicels, or rudimentary (except terminal); 0-1 mm long. Fertile spikelets: Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 3-3.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong; 0.2 mm long; pilose; base obtuse; inserted. Glumes: Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 times length of spikelet; membranous; 2-keeled; keeled laterally. Lower glume intercarinal veins absent. Lower glume surface concave. Upper glume lanceolate; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume muticous. Florets: Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 2-2.4 mm long; hyaline; 0 -veined; ciliate on margins. Fertile lemma lanceolate; 1.6-2.2 mm long; hyaline; without keel. Lemma apex entire; acute; muticous. Palea absent or minute. Flower: Anthers 3; 0.5-0.7 mm long; purple. Fruit: Caryopsis with adherent pericarp; 1.6-2 mm long" (World Grass Descriptions).

Habitat/ecology:  (no habitat/ecology info known by PIER)

Propagation:  Seed

Native range:  West Indies, Mexico, Central and South America (GRIN)

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	Kaua‘i Island	introduced invasive	Snow, Neil/Lau, Alex (2010) (pp. 46-47) Previously misidentified. Vouchers cited: L. Ishii s.n. (BISH 635082), T. Flynn et al. 2679 (BISH), T. Flynn et al. 2717 (BISH), T. Flynn et al. 3547 (BISH), W.L. Wagner & R. Hanford 6278 (BISH), D.R. Herbst 9773 (BISH), C. Imada et al. 99-10 (BISH), C. Imada 2001-58 (BISH)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Colombia Colombia	Colombia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Costa Rica Costa Rica	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Ecuador (Mainland) Ecuador	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
El Salvador El Salvador	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Guatemala Guatemala	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Honduras Honduras	Honduras (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Panama Panama	Panama (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Perú Perú	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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	Topp, J. M. W. (1988) (p. 16)
British Indian Ocean Territory Chagos Archipelago	Diego Garcia Island	introduced invasive	Rivers, Julie (2004) (p. 2)

Comments:  This species is listed as a noxious weed excluded from importation into Hawaii.

Additional information:
Additional online information about Andropogon bicornis is available from the Hawaiian Ecosystems at Risk project (HEAR).

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

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

References:

Clayton, W.D./Harman, K.T./Williamson, H. 2011. World Grass Species: Descriptions, Identification, and Information Retrieval [GrassBase - The Online World Grass Flora]. The Board of Trustees, Royal Botanic Gardens, Kew.

Hafliger, Ernst/Scholz, Hildemar. 1980. Grass weeds, vol. 1. CIBA-GEIGY Ltd., Basle, Switzerland. 142 pp. + plates.

Rivers, Julie. 2004. Botanical survey update of Diego Garcia, Chagos Archipeligo, British Indian Ocean Territory. Naval Facilities Engineering Command, Pacific. 16 pp. plus "List of the higher plants of Diego Garcia".

Snow, Neil/Lau, Alex. 2010. Notes on grasses (Poaceae) in Hawai‘i. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2008. Bishop Museum Occasional Papers 107:46-60.

Topp, J. M. W. 1988. An annotated check list of the flora of Diego Garcia, British Ocean Territory. Atoll Research Bulletin No. 313. Smithsonian Institution, Washington. 21 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.