Dryopteris expansa (C. Presl) Fraser-Jenkins & Jermy
spiny wood fern (spreading wood fern; spreading woodfern)
Dryopteridaceae (Wood Fern family)

Introduction to Vascular Plants


© Kevin Newell     (Photo ID #5388)


E-Flora BC Static Map

Distribution of Dryopteris expansa
Click here to view the full interactive map and legend

Species Information

Deciduous perennial arising in vase-like clusters or singly.
Triangular to oblong-triangular, 20-70 cm long, 10-60 cm wide, sparsely glandular on rachis and lower side of pinnae, 2- to 3-pinnate, the lowest pinnae longer than the upper ones, leaf outlines triangular.

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 Dryopteris expansa

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)
737 0 2750
Slope Gradient (%)
23 0 410

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

350 0 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 0 8
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

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

BAFA(1), BWBS(36), CDF(72), CMA(1), CWH(2243), ESSF(1067), ICH(1419), IDF(59), MH(59), MS(79), SBPS(3), SBS(645)

Habitat and Range

Mesic to wet forests, forest margins and scree slopes from the lowland and steppe to subalpine zones; common in BC; circumpolar, N to AK, YT and NT, E to NF, S to MI, WI, MN, CO, ID and CA; Eurasia.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Dryopteris assimilis S. Walker
Dryopteris dilatata auct. non (Hoffm.) A. Gray
Dryopteris dilatata subsp. americana (Fisch.) Hult╬śn
Dryopteris spinulosa subsp. assimilis
Dryopteris spinulosa var. dilatata auct. non (Hoffm.) Underw.