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

Streptopus amplexifolius var. chalazatus (L.) DC.
clasping twistedstalk (tubercle twistedstalk)

Introduction to Vascular Plants

© Bryan Kelly-McArthur  Email the photographer   (Photo ID #79151)

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Distribution of Streptopus amplexifolius var. chalazatus
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Species Information

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Perennial herb from a thick, short rhizome covered with fibrous roots; stems erect, 40-120 cm tall, branched, sometimes bent at nodes (zigzag), smooth throughout or coarse-hairy on the lower third.
Stem leaves several, egg-shaped to broadly lanceolate, 5-15 cm long, 2-6 cm wide, unstalked, tapering to a clasping base, glaucous beneath, the margins entire or minutely toothed; basal leaves lacking.
Inflorescence of 1 or sometimes 2, stalked flowers drooping from leaf axils, the stalks 2-5 cm long, jointed and abruptly bent or kinked, smooth; flowers greenish-white to yellowish-green, bell-shaped, of 6 similar, distinct tepals, the tepals 8-14 mm long, oblong-lanceolate, concavely tapering to long, pointed, spreading or bent-back tips; stamens 6; pistil 1, 3-chambered.
Berries, egg-shaped to cylindric-ellipsoid, yellow to red, often becoming dark purple, 10-18 mm long; seeds several to many.
Two varieties occur in BC:

1. Stems coarsely hairy below the first branches; leaves with tiny, irregularly spaced teeth; plants mostly from west of the Coast-Cascade Mountains................... var. amplexifolius

1. Stems smooth; leaf margins entire; plants mostly from east of the Coast-Cascade Mountains................... var. chalazatus Fassett

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist forests, streambanks, thickets, avalanche tracks and clearings in the lowland and steppe to subalpine zones; common throughout BC; var. amplexifolius - circumboreal, N to AK, YT and NT, E to NF and S to NC, TN, MN, SD, NM, AZ and CA; Greenland, Eurasia; var. chalazatus - amphiberingian, N to AK, E to AB and S to SD, NM, UT, ID and OR; E Asia.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Streptopus amplexifolius var. chalazatus

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) 1029 1029 1029
Slope Gradient (%) 7 7 7
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
345 344 345
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 4 4
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: ICH(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.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References