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

Sorbus sitchensis var. grayi M. Roem. (Wenzig) C.L. Hitchc.
Sitka mountain-ash (western mountain ash)
Rosaceae (Rose family)

Introduction to Vascular Plants

© Brian Klinkenberg  Email the photographer   (Photo ID #21594)

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Distribution of Sorbus sitchensis var. grayi
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Species Information

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Medium to tall shrub, 1-4 m tall; stems several, erect to spreading, sparingly branched, greyish-red; winter buds and young growth not sticky, somewhat rusty-hairy.
Alternate, deciduous, pinnately compound; leaflets 7 to 11, oblong to oblong-egg-shaped, 2-7 cm long, rounded to blunt at the tip, smooth above, sometimes rusty-hairy below, rather coarsely saw-toothed for not more than 3/4 their length.
Inflorescence a half-rounded, branched cluster of numerous (15 to 80) small flowers, the branches often minutely rusty-hairy; corollas white to cream, the petals 5, oval, 4-6 mm long; calyces mostly smooth, 5-lobed, the lobes triangular; ovaries inferior; stamens 15-20.
Berry-like pomes (like miniature apples), nearly globe-shaped to ellipsoid, 8-10 mm long, red, glaucous, 2- to 5-chambered; seeds 1 or 2 per chamber.
Two sympatric varieties occur in BC:

1. Leaflets entire or toothed mostly above midlength................ var. grayi (Wenzig) C.L. Hitchc.

1. Leaflets toothed one-half to three-quarters their length................. var. sitchensis

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Late Spring
Fruit/Seed characteristics:
Colour: Red
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Mesic to moist open forests, forest edges, streambanks, rockslides, thickets and meadows in the montane to alpine zones; common throughout BC (except NE BC), especially southward; N to AK and YT, E to AB and S to ID, MT and N CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Sorbus sitchensis var. grayi

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) 1064 1064 1064
Slope Gradient (%) 55 55 55
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
318 317 318
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
3 3 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: ICH(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

Sorbus occidentalis (S. Watson) Greene
Sorbus sitchensis subsp. grayi (Wenzig) Calder & Roy L. Taylor

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References