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

Athyrium distentifolium subsp. americanum Tausch ex Opiz (Butters) Hulten
alpine lady fern
Dryopteridaceae (Wood Fern family)

Introduction to Vascular Plants
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E-Flora BC Static Map
Distribution of Athyrium distentifolium subsp. americanum
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Species Information

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Deciduous perennial arising from a short, stout rhizome.
Numerous, upright, narrowly elliptic or lanceolate, 20-70 cm long, 5-25 cm wide, 3-pinnate, ultimate segments oblong, minutely round-toothed.
Fuchs (1974) showed that the name, Athyrium alpestre (Hoppe) Ryland is a later homonym of A. alpestre Clairv. and must be rejected.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry to moist talus slopes, rocks and rocky meadows in the subalpine and alpine zones; infrequent in S BC, rare northward; N to AK, YT and NT, disjunct in PQ and NF and S to CO, UT, NE and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Athyrium distentifolium ssp. americanum

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) 1341 1557 2203
Slope Gradient (%) 0 42 82
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
42 62 315
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 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: CMA(3), ESSF(3), MH(1)


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

Athyrium americanum (Butters) Maxon

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References