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

Streptopus amplexifolius (L.) DC.
clasping twistedstalk (claspleaf twistedstalk)

Introduction to Vascular Plants

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

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Distribution of Streptopus amplexifolius
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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

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) 0 964 2097
Slope Gradient (%) 0 19 410
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
0 0 360
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: AT(5), BAFA(2), BWBS(97), CDF(54), CWH(1504), ESSF(1855), ICH(1608), IDF(144), IMA(2), MH(137), MS(384), PP(8), SBPS(20), SBS(1190), SWB(4)

Ecological Indicator Information

A shade-tolerant/intolerant, submontane to subalpine, circumpolar forb (transcontinental in North America). Occurs on fresh to very moist, nitrogen-rich soils within boreal. temperate, and cool mesothermal climates. Occurrence increases with increasing latitude and precipitation. Sporadic to abundant in submontane to subalpine coniferous forests on water-receiving and water-collecting sites. Usually associated with Abies amabilis, A. lasiocarpa, Athyrium filix-femina, Gymnocarpium dryopteris, Oplopanax horridus, Ribes lacustre, Rubus parviflorus, R.spectabilis, Tiarella trifoliata, and T. unifoliata. A nitrophytic species characteristic of Moder and Mull 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.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References