Aira praecox L., Poaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  yes

Other Latin names:  Aspris praecox (L.) Nash

Common name(s): [more details]

English: early hair grass, yellow hairgrass

Habit:  grass

Description:  "Annual. Culms erect; 2-25 cm long; 2-3 -noded. Leaves mostly basal. Ligule an eciliate membrane; 1.5-3.5 mm long; entire; obtuse. Leaf-blades filiform; involute; 0.5-5 cm long; 0.3-0.5 mm wide. Leaf-blade surface smooth, or scaberulous. Leaf-blade apex acute. Inflorescence a panicle. Panicle spiciform; linear, or oblong; 0.5-4.5 cm long; 0.2-0.8 cm wide. Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear; terete; 1-3 mm long. Fertile spikelets: Spikelets comprising 2 fertile florets; without rhachilla extension. Spikelets oblong to ovate; laterally compressed; 3-3.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes suppressed between florets (florets arising at about the same level). Floret callus pubescent. Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume ovate; 3-3.5 mm long; 1 length of upper glume; membranous; much thinner above; much thinner on margins; 1-keeled; keeled above; 1-3 -veined. Lower glume primary vein scaberulous. Lower glume apex acute. Upper glume ovate; 3-3.5 mm long; 1.1 length of adjacent fertile lemma; membranous; 1-keeled; keeled above; 1-3 -veined. Upper glume primary vein scaberulous. Upper glume apex acute. Florets: Fertile lemma ovate; laterally compressed; lanceolate in profile; 2.7-3.1 mm long; cartilaginous; without keel; 5 -veined. Lemma lateral veins obscure. Lemma surface scaberulous; rough above. Lemma margins involute; covering most of palea. Lemma apex dentate; 3 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.3-0.4 way up back of lemma; geniculate; 3.4-4.3 mm long overall; with twisted column. Palea elliptic; 0.7 length of lemma; cartilaginous; 2 -veined. Palea apex obtuse. Flower: Lodicules 2; lanceolate; membranous. Anthers 3; 0.25-0.3 mm long. Stigmas 2; protandrous; laterally exserted. Caryopsis with adherent pericarp; fusiform; isodiametric; biconvex; estipitate; without sulcus; smooth; apex unappendaged. Embryo 0.2 length of caryopsis. Hilum punctiform. Endosperm farinose"  (GrassBase).

Description from Flora of New Zealand.

Habitat/ecology:  In New Zealand, "dry sandy or stony waste ground, on roadsides, in depleted pasture or in scrub; usually lowland, occasionally montane to subalpine"  (Edgar & Connor, 2000, 1988; p. 296).

Propagation:  Seed

Native range:  Madeira Islands, Europe, western Asia (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. 550)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Atkinson, Rachel/Sawyer, John (2011)
Chile (offshore islands) Juan Fernández Islands	Isla Más Afuera (Alejandro Selkirk Island)	introduced invasive	Danton, Philippe/Perrier, Christophe/Martinez Reyes, Guido (2006) (p. 550)

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)	New South Wales	introduced invasive	National Herbarium of New South Wales (2011) Naturalized on sandy soils.
Canada Province of British Columbia	Canada (British Columbia)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
Canada Canada	Canada (country)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011) Nova Scotia
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 296)
United States (west coast) United States (west coast states)	USA (Oregon)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)
United States (west coast) United States (west coast states)	USA (Washington)	introduced	U.S. Dept. Agr., Nat. Res. Cons. 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)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2011)

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

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

Taxonomic information about Aira praecox 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.

Edgar, E./Connor, H. 2000. Flora of New Zealand, vol. V: Gramineae. Manaaki Whenua Press. .

National Herbarium of New South Wales. 2011. PlantNet: New South Wales Flora online. The Plant Information Network System of the Botanic Gardens Trust Version 2.0. Online resource.

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

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.