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

Botrychium hesperium (Maxon & R.T. Clausen) W.H. Wagner & Lellinger
western moonwort
Ophioglossaceae (Adder's-tongue family)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #84167)

E-Flora BC Static Map
Distribution of Botrychium hesperium
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Species Information

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Deciduous perennial, 3-15 cm tall.
1- to 3-pinnate, 2-3 times length of trophophores, with a single midrib, this midrib sometimes with 2 smaller, less conspicious ribs.
Triangular-shaped to narrowly oblong, dull, grey-green, the stalks up to 1/4 the length of the trophophores; blades 1- to 2-pinnate, up to 6 cm long and up to 5 cm wide; pinnae to 6 pairs, usually approximate or overlapping, with entire or slightly lobed margins; the basal pair of pinnae, dissimilar in size, commonly much larger and more divided than the adjacent pair.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic grassy slopes in montane to subalpine zones; rare in SC and SE BC; E to ON and S to MI, MN, CO and AZ, disjunct in ON and MI.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Botrychium hesperium

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) 1320 1426 1550
Slope Gradient (%) 4 15 25
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
45 112 180
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
3 3 3
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: MS(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

Botrychium lunaria subsp. occidentale A.& D. L÷ve & Kapoor
Botrychium matricariifolium subsp. hesperium Maxon & Clausen
Botrychium matricariifolium var. hesperium (Maxon & Clausen) Broun

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References