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

Poa glauca subsp. rupicola Vahl (Nash ex Rydb.) W.A. Weber
glaucous bluegrass (timberline bluegrass)
Poaceae (Grass family)

Introduction to Vascular Plants
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E-Flora BC Static Map
Distribution of Poa glauca subsp. rupicola
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Species Information

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Perennial, densely tufted grass from fibrous roots; stems erect to spreading, stiff, wiry, straight or slightly decumbent, 5-40 cm tall, usually with 0 or 1 node exserted, uppermost node usually in lowermost 1/3 of stem.
Sheath margins open 4/5-9/10 their length, top stem sheath 3-10 cm long; sterile shoots all or most flowering within a season, next year's shoots set late in the growing season, mostly breaking through sheath bases with indistinct two-keeled buds protecting the scales; basal bladeless leaves present; blades 0.8-2.5 mm wide, mostly flat, appressed or abruptly ascending to spreading, stiff, soon withering; top stem blades usually distinctly shorter than their sheaths (length ratio mostly 0.25-11); ligules 1-4 (5) mm long, the tips rounded to sharp-pointed, minutely rough, the backs more or less finely rough.
Inflorescence an erect panicle, 1-10 cm long, narrowly lanceolate to egg-shaped, contracted or open, sparingly branched and flowered, lowermost internodes less than 1 cm long (rarely more), the primary branches 2 to 3 (5) per node, ascending to spreading, stout, moderately to distinctly rough on angles (rarely nearly smooth), the stalks long-exserted, the spikelet stalks mostly shorter than spikelets; spikelets laterally compressed, 3-8 mm long, (2-) 3- to 5-flowered; glumes narrowly to broadly lanceolate, the keels distinct, the lower ones 3-nerved; rachilla internodes mostly less than 1 mm long, smooth, minutely bumpy, or rough, or hairless or frequently sparsely short straight-haired to moderately minutely soft-hairy; lemmas lanceolate to broadly lanceolate, keeled, 2.5-4 mm long, the tips usually bronze-coloured in part, sharp-pointed, keels and marginal nerves short silky-hairy, lateral nerves usually short silky-hairy or sparsely minutely soft-hairy, between nerves hairless or minutely crisp- to soft-hairy; calluses hairless or cobwebby, often minutely so; palea keels rough, hairless or medially minutely soft-hairy; flowers bisexual (some appearing female-like due to aborted anthers); anthers (1) 1.2-2.5 mm long, well-developed or infrequently aborted late in development.
Two subspecies occur in BC:

1. Lemmas short-hairy between the nerves; calluses of all florets entirely hairless; dwarf alpine plants.................... ssp. rupicola (Nash) W.A. Weber

1. Lemmas variously short-hairy or hairy; calluses webbed or not; if dwarf alpine plants, then calluses of at least the basal florets within a spikelet with at least a vestige of a web or the lemmas smooth between the nerves.................... ssp. glauca

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry ridges, grassy slopes, stony meadows and mossy ledges in the montane to alpine zones; common throughout BC; ssp. glauca - circumpolar, N to AK, YT and NT, E to NF and S to ME, WI, MN, NM, UT, ID and OR; Iceland, Eurasia; ssp. rupicola - N to YT, E to MB and S to SD, NM, AZ and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Poa glauca ssp. rupicola

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) 1390 2254 2501
Slope Gradient (%) 7 33 65
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
80 217 277
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 2 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: AT(20), ESSF(2), MS(1), SWB(1)


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 glauca var. rupicola (Nash ex Rydb.) B. Boivin
Poa rupicola Nash ex Rydb.

Taxonomic and Nomenclatural Links

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General References