Gymnocarpium disjunctum (Rupr.) Ching
western oak fern (Pacific oakfern)
Dryopteridaceae (Wood Fern family)

Introduction to Vascular Plants


© Adolf Ceska     (Photo ID #5695)


E-Flora BC Static Map

Distribution of Gymnocarpium disjunctum
Click here to view the full interactive map and legend

Species Information

Deciduous perennial arising individually at spaced intervals from long creeping rhizomes and usually in large colonies.
On wiry, smooth or sparingly glandular stipes, 10-40 cm long, blades triangular, 10-35 cm long and about the same width, 3-pinnate; ultimate segments lobed.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.


Ecological Framework for Gymnocarpium disjunctum

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)
1078 585 1849
Slope Gradient (%)
26 0 84

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

189 3 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 0 7
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

CWH(1), ESSF(11), ICH(29), IDF(1), MS(1), SBS(7)

Habitat and Range

Moist forests, glades, rocky slopes, streambanks from the lowland to subalpine zones; common throughout all but NE BC; amphiberingian, N to AK, E to AB and S to WY, MT, OR and WA; Kamchatka, Sakhalin.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Dryopteris disjuncta (Rupr.) Morton
Gymnocarpium dryopteris subsp. disjunctum (Rupr.) Sarvela
Gymnocarpium dryopteris var. disjunctum (Rupr.) Ching