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

Sorbus sitchensis M. Roem. var. sitchensis
Sitka mountain-ash (Sitka mountain ash)
Rosaceae (Rose family)

Introduction to Vascular Plants

© Donald L'Heureux  Email the photographer   (Photo ID #76263)

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Distribution of Sorbus sitchensis var. sitchensis
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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

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. sitchensis

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) 1711 1711 1711
Slope Gradient (%) 52 52 52
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
113 112 113
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 2 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: ESSF(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

Pyrus sitchensis (M. Roem.) Piper
Sorbus sitchensis subsp. sitchensis

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References