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

Aira praecox L.
early hairgrass (yellow hairgrass)
Poaceae (Grass family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #29440)

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Distribution of Aira praecox
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Species Information

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Annual, tufted, smooth or more or less rough short-hairy grass from fibrous roots; stems 1 to several, slender, delicate, hollow, 2-12 (20) cm tall.
Sheaths open; blades scarcely 0.5 mm wide, threadlike, in-rolled; ligules 1-3 mm long, pointed to blunt, slightly jagged tips.
Inflorescence a compact, congested and almost continuous, more or less spikelike panicle, mostly 1-3 cm long, the branches erect; spikelet stalks shorter than the spikelets; glumes (2.7) 3-3.2 (3.5) mm long; lemmas (2.5) 3-3.2 (3.5) mm long, usually lightly rough short-hairy, awned, the awns 2-3 mm long; anthers about 0.2 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Vernally moist to dry gravelly or rocky bluffs and grassy meadows; common on S Vancouver Island, the Gulf Islands and lower mainland, infrequent N to the Queen Charlotte Islands; introduced from Europe.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Aira praecox

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) 0 281 2100
Slope Gradient (%) 0 38 120
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
10 135 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 1 6
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(32), CWH(18), ICH(2), MS(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

Aspris praecox (L.) Nash

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References