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

Astragalus alpinus L.
Alpine Milk-vetch (Alaskan Sagebrush; alpine milkvetch)
Fabaceae (Pea family)

Introduction to Vascular Plants

© Virginia Skilton  Email the photographer   (Photo ID #2755)

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Distribution of Astragalus alpinus
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SUBTAXA PRESENT IN BC
Astragalus alpinus var. alpinus

Species Information

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General:
Low mat-forming perennial herb from a taproot and rhizomes; stems few to several, decumbent to ascending, 5-35 cm long, slender, branched, with short, appressed, unbranched hairs.
Leaves:
Alternate, pinnately compound, 5-15 cm long, stalked; leaflets 13 to 25, egg-shaped to oblong-elliptic, rounded to notched at the tip, 5-15 (20) mm long, appressed-hairy, the stalks equal to or longer than the leaves; stipules 1-8 mm long, the lower ones joined and clasping the stem.
Flowers:
Inflorescence a short, axillary raceme of 5 to 30 pea-like flowers, the flowers ascending at first, later nodding, the racemes 1-6 cm long on stalks from shorter to longer than the leaves; corollas pinkish- to bluish-purple, often white towards the base, 7-15 mm long, the darker-purple keel about as long as the banner, both longer than the wings; calyces bell-shaped, short-black-hairy, 3-6 mm long, the awl-shaped teeth about half the length of the tube.
Fruits:
Pods, ellipsoid-oblong, drooping from a slender stalk about as long (1-3 mm) as the calyx teeth, black appressed-hairy, membranous, 8-17 mm long, grooved below, almost 2-chambered, the partition sometimes nearly complete.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Moist to mesic streambanks, river terraces, meadows, rocky slopes, heath, tundra and open forests in the montane to alpine zones; frequent in BC east of the Coast-Cascade Mountains; N to AK, YT and NT, E to NF and S to ID, MT, NM, NV, WA and NE OR.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Astragalus alpinus

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) 33 1805 2682
Slope Gradient (%) 0 27 100
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
10 171 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 2 6
Modal Nutrient Regime
Class
C
Number of field plots
 species was recorded in:
218
Modal BEC Zone Class
ESSF
All BEC Zones (# of stations/zone) species was recorded in: AT(42), BAFA(26), BWBS(10), ESSF(74), IMA(16), MH(12), MS(8), SBPS(5), SBS(1), SWB(12)

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.

Taxonomic and Nomenclatural Links

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General References