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

Listera caurina Piper
northwestern twayblade
Orchidaceae (Orchid family)

Introduction to Vascular Plants

© Mark Gardiner  Email the photographer   (Photo ID #66585)

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Distribution of Listera caurina
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Species Information

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Perennial herb from slender rhizomes, with fibrous roots; stems 10-30 cm tall, slender, with 2 leaves, glandular-hairy above.
Two, near middle of stem, roughly opposite, broadly egg-shaped, 2.5-7 cm long, 1.8-4.5 cm wide, abruptly tapered to base.
Inflorescence a few- to many-flowered, terminal raceme, the flowers greenish to yellowish; sepals 3-4 mm long, narrowly lanceolate, 1-veined, distinct, spreading; petals similar to sepals, 2.8-3.5 mm long; lip 4.5-7 mm long, about 3.5 mm wide, wedge- to egg-shaped, rounded or with shallow notch at tip, with a pair of lateral threadlike teeth at base; column 1.5-2.5 mm long.
Capsules, spreading, egg-shaped, to 7 mm long.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist forests, bogs and meadows in the montane and subalpine zones; frequent on the coast, infrequent in NW BC and E of the Coast-Cascade Mountains south of 55 degrees N; N to AK, E to AB and S to WY, ID and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Listera caurina

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) 0 497 1943
Slope Gradient (%) 0 26 350
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 237 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 4 8
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: BWBS(4), CWH(745), ESSF(42), ICH(80), IDF(3), MH(88), MS(6), SBPS(1), SBS(34)

Ecological Indicator Information

A shade-tolerant, submontane to montane, Western North American forb distributed more in the Pacific than the Cordilleran region. Occurs on fresh to very moist, nutrient-medium soils within boreal, wet cool temperate, and cool mesothermal climates; its occurrence decreases with increasing elevation and continentality. Scattered in dense coniferous forests on water-shedding and water-receiving sites; often associated with Blechnum spicant, Gaultheria shallon, Hylocomium splendens, Rhytidiadelphus loreus, Plagiothecium undulatum, and Vaccinium alaskaense. Characteristic of friable Mors and acidic Moder humus forms.

SourceIndicator Plants of Coastal British Columbia (Information applies to coastal locations only)


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

Listera banksiana auct. non Lindl.
Neottia caurina (Piper) Szlach.
Ophrys caurina (Piper) Rydb.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References