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

Astragalus purshii Douglas ex Hook.
woollypod milk-vetch (woollypod milkvetch)
Fabaceae (Pea family)

Introduction to Vascular Plants

© Virginia Skilton  Email the photographer   (Photo ID #25503)

E-Flora BC Static Map
Distribution of Astragalus purshii
Click here to view our interactive map and legend
Details about map content are available here
Click on the map dots to view record details.

Species Information

Click on the image below to view an expanded illustration for this species.


Perennial herb from a taproot and branching stem-base; stems prostrate, tufted or mat-forming, 5-10 cm long, greyish-woolly with unbranched hairs.
Alternate, pinnately compound, crowded, 2-15 cm long, white-woolly; leaflets 5 to 19, elliptic or oval to oblong, 5-20 mm long; stipules membranous, lanceolate, long-pointed, 3-15 mm long, usually exceeding the internodes, not joined at the base.
Inflorescence a short, axillary raceme of 2 to 10 pea-like flowers, the raceme-stalks from shorter to longer than the leaves, sometimes almost lacking, arching or lying on the ground in fruit; corollas yellowish-white to reddish-purple, 1-3 cm long, the banner longer than the wings and the blunt keel; calyces cylindric, 12-16 mm long, black- to grey-hairy, the narrowly lanceolate teeth 1/3-1/2 as long as the tube.
Pods, egg-shaped or narrowly ellipsoid, spreading, unstalked, 1-2.5 cm long, leathery, greyish-woolly, somewhat flattened, straight to curved, 1-chambered.
Two intergrading varieties of this highly variable species are recognized in BC.

1. Flowers yellowish-white or pale lavender, the keels purple-tipped; pods nearly straight.................. var. purshii

1. Flowers reddish-purple; pods curved and strongly grooved............... var. glareosus (Dougl. ex Hook.) Barn.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Mid Spring
Fruit/Seed characteristics:
Colour: Black
Present from Spring to Summer
Source:  The USDA

Habitat / Range

Dry grasslands and sagebrush scrub in the steppe and lower montane zones; common in SC BC; E to AB and S to SD, ND, CO, NV and NE CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Astragalus purshii

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) 225 637 1535
Slope Gradient (%) 0 28 70
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
20 198 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 2 6
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: BG(59), IDF(13), MS(2), PP(41)


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