Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Habit:  grass

Description:  "Annual; caespitose. Culms 30-60 cm long. Ligule an eciliate membrane. Leaf-blades 8-15 cm long; 2-7 mm wide. Inflorescence a panicle. Panicle spiciform; linear, or oblong; 1.5-4.5 cm long; 1-1.4 cm wide. Spikelets ascending; solitary. Fertile spikelets sessile. Fertile spikelets: Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets obovate; laterally compressed; compressed strongly; 4.7-6.2 mm long; breaking up at maturity; disarticulating below each fertile floret. Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume elliptic; 4.7-6.2 mm long; 1 length of upper glume; chartaceous; 1-keeled; winged on keel; winged narrowly; 3-5 -veined. Lower glume primary vein scabrous. Lower glume surface scabrous; rough on veins. Lower glume apex acute, or acuminate. Upper glume elliptic; 4.7-6.2 mm long; 1.5 length of adjacent fertile lemma; chartaceous; 1-keeled; winged on keel; 3-5 -veined. Upper glume primary vein scabrous. Upper glume surface scabrous; rough on veins. Upper glume apex acute, or acuminate. Florets: Basal sterile florets similar; barren; without significant palea; attached to and deciduous with the fertile. Lemma of lower sterile floret linear; 1.5-1.9 mm long; 0.5 length of fertile lemma; glabrous. Fertile lemma elliptic; laterally compressed; 3.2-4.2 mm long; cartilaginous; shiny; keeled; 5 -veined. Lemma surface pubescent; hairy all along. Lemma apex acute. Palea cartilaginous; 2 -veined; without keels. Palea surface pubescent; hairy on back. Flower: Lodicules 2; membranous. Anthers 3. Ovary glabrous. Caryopsis with adherent pericarp; 2.1-2.2 mm long. Hilum linear"  (GrassBase).

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

Propagation:  Seed

Native range:  Chile (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)
Chile (offshore islands) Juan Fernández Islands	Isla Más a Tierra (Robinson Crusoe Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 556)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Chile (continental) Chile	Chile (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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

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

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

References:

Atkinson, Rachel/Sawyer, John. 2011. Naturalized species in the Juan Fernández Archipelago, Chile. Unpublished spreadsheet.

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.

Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido. 2006. Nouveau catalogue de la flore vaculaire de l'archipel Juan Fernández (Chile) [Nuevo catálogo de la flora vacular del Archipélago Juan Fernández (Chile)]. Acta Bot. Gallica 153(4):399-587.

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