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

Acer glabrum Torr.
Douglas maple (Rocky Mountain maple)
Sapindaceae (Horse-chestnut family)
(Previously in Aceraceae)

Introduction to Vascular Plants

© Doug Skilton  Email the photographer   (Photo ID #2693)

E-Flora BC Static Map
Distribution of Acer glabrum
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Acer glabrum var. douglasii

Species Information

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Deciduous shrub or small tree, up to 10 m tall; stems branching, glabrous, young twigs reddish; bark greyish to reddish-purple.
Opposite, 2-12 cm wide, 3- to 5-lobed, glabrous to sparsely glandular short-hairy, coarsely toothed, paler on the lower surface, turning yellow to orange or crimson in fall.
Inflorescence of flat-topped, terminal or axillary clusters of about 10 flowers, male and female flowers on separate or same plants, appearing with the leaves; petals and sepals yellowish-green.
Winged, in pairs, 2-3 cm long, greenish-brown, pairs attached in a V-shape.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

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

Habitat / Range

Mesic to dry forests and rocky slopes in the lowland and montane zones; common throughout BC, except Queen Charlotte Islands and adjacent coast and NE BC; N to SE AK, E to AB and S to OR and MT.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Acer glabrum

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) 0 936 2500
Slope Gradient (%) 0 33 235
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 202 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 3 8
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(2), BG(58), BWBS(1), CDF(4), CWH(219), ESSF(170), ICH(2257), IDF(834), MS(508), PP(69), SBPS(2), SBS(480)

Ecological Indicator Information

A shade-tolerant to shade-intolerant, montane to subalpine, Western North American deciduous shrub distributed more in the Cordilleran than the Pacific region. Occurs on nitrogen-rich, water-shedding and water-receiving sites within continental boreal, cool temperate, cool semiarid, and occasionally cool mesothermal climates. Scattered throughout coastal British Columbia; its occurrence increases with increasing continentality. Common on eastern Vancouver Island and in Skeena River valley. Grows with vine maple in the southem coast-interior ecotone. Like A. circinatum, it inhabits open-canopy forests, clearings, and primary succession stages on fragmental colluvial soils. Regenerates abundantly from stump sprouts; it hinders regeneration and growth of shade­intolerant conifers. Characteristic of Moder and Mull humus forms.

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 not evaluated, unknown or variable.

Synonyms and Alternate Names

Acer diffusum Greene
Acer glabrum subsp. diffusum (Greene) E. Murray
Acer glabrum subsp. neomexicanum (Greene) E. Murray
Acer glabrum var. parviflorum E. Murray
Acer neomexicanum Greene

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References