Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Chaetochloa macrostachya (Kunth) Scribn. & Merr.

Common name(s): [more details]

English: plains bristlegrass

Habit:  grass

Description:  "Plants perennial; densely cespitose. Culms 60-120 cm, rarely branched distally, scabrous below the nodes and panicles. Sheaths keeled, glabrous, usually with a few white hairs at the throat; ligules 2-4 mm, densely ciliate; blades 15-20 cm long, 7-15 mm wide, flat, adaxial surface scabrous. Panicles 10-30 cm long, 1-2 cm wide, uniformly thick from the base to the apex, dense, rarely lobed basally; rachises scabrous and loosely pilose; bristles usually solitary, 10-20 mm, soft, antrorsely scabrous. Spikelets 2-2.3 mm, subspherical. Lower glumes 1/3-1/2 as long as the spikelets, 3-5-veined; upper glumes about 3/4 as long as the spikelets, 5-7-veined; lower lemmas equaling the upper lemmas, 5-veined; lower paleas nearly equaling the upper paleas in length and width; upper lemmas transversely rugose; upper paleas convex, ovate" (Manual of Grasses for North America: Grass Manual on the Web).

Description from GrassBase.

Habitat/ecology:  Desert grasslands in the southwestern US (Manual of Grasses for North America: Grass Manual on the Web).

Propagation:  Seed

Native range:  United States, Mexico, Cuba, Nicaragua (GRIN).  "Setaria macrostachya is abundant in the desert grasslands of the southwestern United States, particularly in southern Arizona and Texas. It extends south through the highlands of central Mexico. It also grows in the West Indies, but is not common there" (Manual of Grasses for North America: Grass Manual on the Web).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Ecuador (Galápagos Islands) San Cristóbal Group	San Cristóbal Island	introduced invasive	Charles Darwin Foundation (2008)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mexico Mexico	Mexico (United Mexican States)	native	Utah State University (2004)
Nicaragua Nicaragua	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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	Utah State University (2004)

Comments:  Probably not native to the Galápagos Islands, possibly introduced, per Charles Darwin Research Station.

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

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

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

References:

Charles Darwin Foundation. 2008. Database inventory of introduced plant species in the rural and urban zones of Galapagos. Charles Darwin Foundation, Galapagos, Ecuador.

Charles Darwin Research Station. 2005. CDRS Herbarium records.

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

Utah State University. 2004. Manual of Grasses for North America: Grass Manual on the Web.