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

Physaria didymocarpa (Hook.) A. Gray
Double Twinpod (common twinpod)
Brassicaceae (Mustard family)

Introduction to Vascular Plants

© RĂ©al Sarrazin  Email the photographer   (Photo ID #26962)

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Distribution of Physaria didymocarpa
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Physaria didymocarpa ssp. didymocarpa

Species Information

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Tufted perennial from a heavy-rooted, often branched stem-base; stems numerous, decumbent, 2-17 cm long, with silvery starlike hairs, these not closely appressed.
Basal leaves numerous, in a rosette, withering and persistent, 2-8 cm long, blades egg-shaped, mostly obtuse, with few inconspicuous teeth or toothed, rarely entire, with narrow to wide winged stalks, these about as long as the blades, silvery; stem leaves several, reduced, oblanceolate, entire or with occasional tooth.
Racemes congested, elongating in fruit; flower stalks spreading, straight or slightly curved, 8-12 mm long; petals yellow, 9-12 mm long, broadly spoon-shaped or egg-shaped.
Silicles, paired, much-inflated, 1-2 cm long, at least as wide, base very slightly heart-shaped, apical sinus narrow, nearly closed, 2-4 mm deep, loosely hairy with rays of hairs spreading; beaks 6-9 mm long; seeds 2-3 per chamber.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Dry grasslands, shrublands and rocky slopes in the montane to alpine zones; rare in SE BC; E to SW AB and S to WA, ID, and WY.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Physaria didymocarpa

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) 1050 1783 2180
Slope Gradient (%) 54 58 65
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
106 194 225
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 2 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: ESSF(2), IDF(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

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General References