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

Cassiope tetragona (L.) D. Don
four-angled mountain-heather (white arctic mountain heather)
Ericaceae (Crowberry family)

Introduction to Vascular Plants

© Allan Carson  Email the photographer   (Photo ID #17741)

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Distribution of Cassiope tetragona
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Species Information

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Coarse dwarf shrub, mat-forming; stems 4-angled, stiff, ascending to erect, 5-30 cm long, finely hairy.
Evergreen, opposite, distinctly in 4 rows, appressed, nearly concealing the stems, egg- to lance-shaped, 2-6 mm long, deeply grooved on the back, conspicuously finely hairy and minutely fringed on outer surface, usually glabrous or glandular on concave inner surface; unstalked.
Solitary in leaf axils to few near branch tips, nodding on stalks 10-25 mm long, longer than the subtending leaves; corollas white or pinkish, bell-shaped, (4) 5-10 mm long, lobes egg-shaped, almost 1/2 the length of the tube; calyces reddish, egg-shaped, 2-2.5 mm long, entire; stamens not enlarged at the base.
Capsules, globe-shaped, glabrous, about 3 mm wide.
Two varieties are recognized in BC:

1. Flowers usually less than 5 (6) mm long, the flower stalks generally less than twice the length of the subtending leaves........................ var. saximontana (Small) C. L. Hitchc.

1. Flowers 6-10 mm long, the flower stalks proportionately longer, more than twice the length of the subtending leaves........................... var. tetragona

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

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

Habitat / Range

Moist to dry meadows, heath, and rocky slopes in the subalpine and alpine zones; frequent in BC in and E of the Coast-Cascade Mountains; circumpolar, N to AK, YT, and NT, E to N PQ, and S to WA and MT; Eurasia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Cassiope tetragona

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) 34 1803 3000
Slope Gradient (%) 0 23 84
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 11 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 3 7
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(15), BAFA(127), CWH(1), ESSF(90), IMA(42), MH(5), SWB(30)

Ecological Indicator Information

A very shade-intolerant, alpine, circumpolar, evergreen shrub (transcontinental in North America). Occurs in continental alpine tundra and subalpine boreal climates on fresh to very moist, nitrogen-medium soils. Scattered to plentiful in heath communities affected by snow-drifts; its occurrence increases with increasing continentality. Often associated with Cassiope mertensiana and Phyllodoce glanduliflora in the coast-interior ecotone. Characteristic of alpine communities.

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 alpine tundra & boreal.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References