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

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

Introduction to Vascular Plants

© Paul Handford  Email the photographer   (Photo ID #65439)

E-Flora BC Static Map
Distribution of Astragalus purshii var. purshii
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Species Information

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General:
Perennial herb from a taproot and branching stem-base; stems prostrate, tufted or mat-forming, 5-10 cm long, greyish-woolly with unbranched hairs.
Leaves:
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.
Flowers:
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.
Fruits:
Pods, egg-shaped or narrowly ellipsoid, spreading, unstalked, 1-2.5 cm long, leathery, greyish-woolly, somewhat flattened, straight to curved, 1-chambered.
Notes:
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

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

Ecology

Ecological Framework for Astragalus purshii var. 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

Minimum

Average

Maximum

Elevation (metres) 635 869 1104
Slope Gradient (%) 11 16 22
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
150 64 340
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
1 2 4
Modal Nutrient Regime
Class
A
Number of field plots
 species was recorded in:
2
Modal BEC Zone Class
BG
All BEC Zones (# of stations/zone) species was recorded in: BG(1), IDF(1)

Climate

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

Astragalus incurvus (Rydb.) Abrams
Astragalus purshii var. interior M.E. Jones

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References