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

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

Introduction to Vascular Plants

© Adolf Ceska  Email the photographer   (Photo ID #5695)

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Distribution of Gymnocarpium disjunctum
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Species Information

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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.

Source: The Illustrated Flora of British Columbia

Habitat / 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.

Source: The Illustrated Flora of British Columbia


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) 585 1078 1849
Slope Gradient (%) 0 26 84
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
3 189 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 4 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: CWH(1), ESSF(11), ICH(29), IDF(1), MS(1), SBS(7)


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

Dryopteris disjuncta (Rupr.) Morton
Gymnocarpium dryopteris subsp. disjunctum (Rupr.) Sarvela
Gymnocarpium dryopteris var. disjunctum (Rupr.) Ching

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References