Polypogon imberbis (Phil.) Johow, Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Other Latin names:  Chaetotropis imberbis (Phil.) Björkman; Nowodworskya imberbis Phil.

Habit:  grass

Description:  "Perennial; caespitose. Culms 15-80 cm long. Leaf-sheaths smooth, or antrorsely scabrous. Ligule an eciliate membrane; 2-5 mm long; scaberulous on abaxial surface. Leaf-blades flat, or convolute; 10-15 cm long; 2-8 mm wide. Leaf-blade margins scabrous. Inflorescence a panicle. Panicle spiciform; linear, or oblong; interrupted; 5-25 cm long. Primary panicle branches 0.5-5 cm long. Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; 1-3 mm long; scabrous. Fertile spikelets: Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 3.5-4.5 mm long; falling entire; deciduous with the pedicel. Floret callus glabrous. Glumes similar; exceeding apex of florets; firmer than fertile lemma; gaping. Lower glume lanceolate; 3.5-4.5 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface scabrous. Lower glume apex acute; awned; 1 -awned. Lower glume awn 1-2 mm long. Upper glume lanceolate; 3.5-4.5 mm long; 2.2 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface scabrous. Upper glume apex acute; awned; 1 -awned. Upper glume awn 1-2 mm long. Florets: Fertile lemma oblong; 1.6-2 mm long; membranous; without keel; 5 -veined. Lemma apex dentate; 4 -fid; truncate; muticous, or mucronate. Principal lemma awn from a sinus. Palea 0.6-0.7 length of lemma; hyaline. Flower: Lodicules 2; 0.4 mm long; membranous. Anthers 3; 0.7-0.8 mm long. Caryopsis with adherent pericarp; fusiform; 1.5 mm long. Endosperm soft"  (GrassBase).

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

Propagation:  Seed

Native range:  Argentina, Brazil, Chile, Uruguay (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) As Chaetotropis imberbis (Phil.) Björkman
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 552) As Chaetotropis imberbis (Phil.) Björkman
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011) As Chaetotropis imberbis (Phil.) Björkman
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 552) As Chaetotropis imberbis (Phil.) Björkman

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
South America (Pacific rim) South America (Pacific rim)	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control:  If you know of control methods for Polypogon imberbis, please let us know.