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

Astragalus tenellus Pursh
pulse milk-vetch (looseflower milkvetch)
Fabaceae (Pea family)

Introduction to Vascular Plants

© Paul Handford  Email the photographer   (Photo ID #65448)

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Distribution of Astragalus tenellus
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Species Information

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General:
Perennial herb from a thick taproot and knotty or short-branched stem-base; stems few to many in bushy clumps, ascending to erect, sometimes sprawling at higher elevations, 20-60 cm tall, branched, short-hairy with appressed, unbranched hairs.
Leaves:
Alternate, pinnately compound, 3-8 cm long, the stalks very short or lacking; leaflets 9 to 25, narrowly lanceolate to oblong, rounded at the tip, 0.8-2.5 cm long, finely appressed-hairy below, commonly glabrous above; stipules joined opposite the leaf stalks and clasping the stem, 3-6 mm long, the lowest papery and often blackish, the upper less strongly united.
Flowers:
Inflorescence a loose, axillary raceme of 4 to 20 pea-like flowers, the flowers at first ascending, later nodding, the racemes 3-10 cm long on short (1-4 cm) stalks; corollas 6-9 mm long, yellowish-white but sometimes pink-tinged, the keel purple-tipped, the banner slightly longer than the wings, which are 1-2 mm longer than the keel; calyces bell-shaped, appressed-hairy with black or white hairs, 2.5-4 mm long, the awl-shaped teeth 2/3 as long as the tube.
Fruits:
Pods, oblong, flattened, 7-18 mm long, drooping from the 1- to 5-mm long stalk, papery-membranous, glabrous, often mottled or stippled, net-veined when mature, 1-chambered.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic to dry grassy slopes and bluffs, sandy and gravelly flats, roadcuts and open forests from the steppe to lower subalpine zones; common in BC south of 57degreeN and east of the Coast-Cascade Mountains; N to S YT, E to MB and S to MN, NE, NM, NV, ID and MT.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Astragalus tenellus

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) 426 892 1560
Slope Gradient (%) 0 24 90
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
3 196 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
0 3 5
Modal Nutrient Regime
Class
C
Number of field plots
 species was recorded in:
123
Modal BEC Zone Class
BG
All BEC Zones (# of stations/zone) species was recorded in: BG(51), BWBS(5), ICH(1), IDF(47), MS(4), PP(12), SWB(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 tenellus var. strigulosus (Rydb.) F.J. Herm.
Homalobus tenellus (Pursh) Britton

Taxonomic and Nomenclatural Links

Additional Photo Sources

Related Databases

General References