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

Poa macrantha Vasey
dune bluegrass (seashore bluegrass)
Poaceae (Grass family)

Introduction to Vascular Plants

© Adolf Ceska  Email the photographer   (Photo ID #20377)

E-Flora BC Static Map
Distribution of Poa macrantha
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Species Information

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Perennial, loosely tufted grass from fibrous roots, rhizomes and stolons, these shoots stout, to 4 m long; stems erect or decumbent, stout, 10-60 cm tall/long.
Sheath margins open about 1/2 their length, sheaths hairless or sparsely rough, the projections pointed downward; sterile shoots mainly emerging inside sheaths with well developed two-keeled buds protecting the scales; blades 2-4 mm wide, somewhat curved, in-rolled, thick, outer surface smooth, inner surface of sterile shoots usually distinctly rough or minutely soft-hairy; ligules 1-5 mm long, the tips rounded to sharp-pointed, the backs rough.
Inflorescence an erect panicle, 3-15 cm long, congested, often interrupted; stalks smooth to moderately rough, hairless; central axis and branches slightly to moderately rough, branches 1 to 2 per node; spikelets laterally compressed, 9-16 mm long, 3- to 6-flowered; lower glumes 3-nerved, the upper ones usually more than 7 mm long; rachillas smooth, silky-hairy (rarely hairless); lemmas lanceolate, (6) 7.5-11 mm long, the tips sharp-pointed, 5- to 7- (11-) nerved, surface smooth or rough, the keels, marginal nerves and some lateral nerves minutely soft- to short silky-hairy, smooth and hairless to rough or minutely soft-hairy between the nerves; calluses hairless, diffusely short-cobwebby, or with a crown of wavy hairs; palea keels rough; flowers unisexual; anthers vestigial or 2-5 mm long.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Late Winter
Fruit/Seed characteristics:
Colour: Brown
Present over the Spring
Source:  The USDA

Habitat / Range

Shifting sands (especially dunes) in the lowland zone; infrequent in coastal BC; N SE AK and S to N CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Poa macrantha

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 5 13
Slope Gradient (%) 0 3 20
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
200 232 280
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 1 2
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: CWH(9)


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 not evaluated, unknown or variable.

Synonyms and Alternate Names

Poa douglasii subsp. macrantha (Vasey) D.D. Keck
Poa douglasii var. macrantha (Vasey) Boivin

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References