E-Flora BC: Electronic Atlas of the Flora of British Columbia

Aira caryophyllea L.
silver hairgrass
Poaceae (Grass family)

Introduction to Vascular Plants

© Adolf Ceska  Email the photographer   (Photo ID #13635)

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Distribution of Aira caryophyllea
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Species Information

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Annual, tufted grass from fibrous roots; stems 1 to several, slender, delicate, hollow, smooth or short-hairy below the nodes, 5-30 cm tall.
Sheaths open; blades 4-15 cm long, 0.3-0.7 mm wide, threadlike, in-rolled; ligules 1.5-3.5 mm long, blunt, minutely rough to short-hairy, more or less irregular and jagged.
Inflorescence an open panicle, 2-6 cm long and nearly as wide; spikelet stalks longer than spikelets; glumes 2.5-2.8 (3) mm long; lemmas 2-2.3 mm long, awned, the awns 2.5-3.5 mm long; anthers about 0.3 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Vernally moist to dry, gravelly or rocky, open sites; common on S Vancouver Island, less frequent in the Gulf Islands and lower mainland, rare in the Queen Charlotte Islands; introduced from Europe.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Aira caryophyllea

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 15 171 382
Slope Gradient (%) 0 38 210
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
19 177 280
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 1 3
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CDF(16), CWH(4), IDF(1)

Ecological Indicator Information

Very shade-intolerant, submontane to montane, European grasses introduced to Pacific and Atlantic North America. Both Aira caryophyllea and Aira praecox occur in maritime to su maritime summer­dry cool mesothermal climates on very dry to moderately dry soils, and, A. praecox, on nitrogen-poor soils. Scattered in the open and open-canopy coniferous forests on very shallow and strongly drained soils of rock outcrops. Characteristic of moisture-deficient sites.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is cool mesothermal.

Synonyms and Alternate Names

Aira capillaris Host, non Savi
Aira caryophyllea var. capillaris (Host) Mutel
Aira elegans subsp. ambigua (Arcang.) Holub
Aira elegantissima Schur
Aspris capillaris (Host) Hitchc.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References