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

Astragalus miser var. serotinus Douglas ex Hook. (A. Gray ex Cooper) Barneby
timber milk-vetch (timber milkvetch)
Fabaceae (Pea family)

Introduction to Vascular Plants

© Curtis Bjork  Email the photographer   (Photo ID #16545)

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Distribution of Astragalus miser var. serotinus
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Species Information

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Perennial herb from a taproot and branching stem-base, often with rhizomes; stems several to many, tufted, decumbent to erect, 10-40 cm long/tall, with short, appressed, unbranched (in ours) hairs.
Alternate, pinnately compound, 3-15 cm long, stalked; leaflets 7 to 21, linear to lance-oblong or oval, 5-30 mm long, greyish appressed-hairy on both surfaces or green and glabrous above; stipules lanceolate, 2-7 mm long, fused into a membranous sheath.
Inflorescence a loose to compact, axillary raceme of 3 to 20 more or less spreading, pea-like flowers, the racemes 1-10 cm long on slender stalks from shorter to longer than the leaves; corollas 8-12 mm long, from white or yellowish to bluish, the banner and wings with blue to pinkish-purple pencilling, the banner slightly longer than the wings and the purple-tipped keel; calyces 3-6 mm long, white or black appressed-hairy, the teeth triangular-awl-shaped, about 1 mm long.
Pods, narrowly oblong, nearly unstalked, drooping, glabrous to hairy, 1.5-2.5 cm long, flattened or not, becoming papery, 1-chambered.
Two varieties occur in BC:

1. Leaflets equally hairy on both sides, the foliage silvery or frosted; calyces 4.5-6 mm long; keels 8-10.5 mm long.......................... var. miser

1. Leaflets glabrous or becoming so above, if hairy then the flowers much smaller; calyces less than 4 mm long; keels 6-8 mm long.............................. var. serotinus (A. Gray) Barn.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic to dry grasslands, sagebrush flats, meadows, thickets, bluffs, roadsides, rocky slopes and forest openings from the steppe to lower alpine zones; common in BC S of 53degreeN and E of the Coast-Cascade Mountains, rare northward to 57degreeN; E to SW AB and S to C WA (var. serotinus) and S to ID, MT and NE WA (var. miser).

Source: The Illustrated Flora of British Columbia


Ecological Framework for Astragalus miser var. serotinus

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) 420 927 1470
Slope Gradient (%) 0 23 64
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
14 221 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 3 5
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(1), IDF(22), PP(9)


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 decumbens var. serotinus (A. Gray ex Cooper) M.E. Jones
Astragalus serotinus A. Gray ex Cooper

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References