Aira caryophyllea L., Poaceae

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Present on Pacific Islands?  yes

Threat only at high elevations?  yes

Common name(s): [more details]

English: silver hairgrass

French: aira caryophyllée, canche caryophyllée caryophyllée

Habit:  grass

Description:  "Annuals; culms solitary or few, sometimes numerous, forming large perennial clumps resulting from reseeding, 3-40 cm tall.  Sheaths glabrous, open to base; ligule membranous, triangular, 4-5 mm long, apex entire but becoming lacerate; blades filiform or subsetaceous, usually 1-5 cm long, up to 1 mm wide.  Inflorescences paniculate, loose, ovate to oblong, 1-12 cm long, the branches bare at base; spikelets 2, ca. 3 mm long, clustered toward tips of capillary branches, pedicels 0.7-3.5 times as long as the spikelet and pear-shaped at apex; glumes pale brown, chartaceous, ovate, 2.3-3.5 mm long, enclosing the florets, nerves ± prominent, surface lustrous, glabrous except sparsely scabrous along keel, apex acute, slightly erose; lemmas dark reddish brown, narrowly ovate, 2-2.5 mm long, short-scabrous, apex acuminate, 2-lobed, apical teeth setaceous, awn 3-4 mm long, slightly geniculate, inserted below midpoint on dorsal face, rarely absent, callus minutely bearded at lateral margins of floret; palea similar in color, vestiture, and texture to lemma, 1.5-2 mm long, apex acuminate, somewhat adnate to caryopsis.  Caryopsis 1-1.5 mm long, ca. 0.5 mm in diameter, weakly adnate to lemma and palea and remaining enclosed within them"  (Wagner et al., 1999; p. 1495).

Description from World Grass Species.

Habitat/ecology:  "Coastal vegetation, heath- and woodland, riparian habitats, wetlands, rock outcrops" (Weber, 2003; p. 33).

In Hawai‘i, "naturalized in pastures and on lava, often near moist areas, and in subalpine shrubland, 1,050-2,440 m"  (Wagner et al., 1999; p. 1495).

Propagation:  Seed

Native range:  Europe, Africa and 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
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1495)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Lorence, David H./Flynn, Tim (1997) (p. 11) Voucher cited: Flynn 5843 (PTBG)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1495)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1495) Voucher cited: Munro 374 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wood, K. R. (2006) (p. 18) Voucher cited: K. R. Wood & J. Lau 10636 (BISH, PTBG, US)

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)	Australia (continental)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2007)
Chile (continental) Chile	Chile (Republic of)		Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. (1979) (p. 12)
Mexico Mexico	Mexico (United Mexican States)	introduced	Weber, Ewald (2003) (p. 33)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Edgar, E./Connor, H. (2000) (p. 294) "Usually in dry, stony, or sandy ground, or in disturbed sites; rarely in damp ground at swamp or lagoon margins; sea level to subalpine".

Control: 

Physical:  Small patches may be dug out.

Chemical:  Spray with grass-selective herbicides.

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

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

References:

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

Holm, Leroy/Pancho, Juan V./Herberger, James P./Plucknett, Donald L. 1979. A geographical atlas of world weeds. John Wiley & Sons, New York. 391 pp.

Lorence, David H./Flynn, Tim. 1997. New naturalized plant records for Kaua‘i. In: Evenhuis, Neal L. and Miller, Scott, E., eds. Records of the Hawaii Biological Survey for 1996. Part 2: Notes. Bishop Museum Occasional Papers. 49:9-13.

U.S. Dept. Agr., Agr. Res. Serv. 2007. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press/Bishop Museum Press, Honolulu. 1919 pp. (two volumes).

Weber, Ewald. 2003. Invasive plants of the World. CABI Publishing, CAB International, Wallingford, UK. 548 pp.

Wood, K. R. 2006. New plant records and rediscoveries within the Hawaiian Islands. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2004-2005. Part 2: Notes. Bishop Museum Occasional Papers 88:15-19.