Astragalus flexuosus (Slender Milkvetch)
|Also known as:
|sun; sandy prairie, bluffs
|8 to 16 inches
|Wetland Indicator Status:
|MN county distribution (click map to enlarge):
|National distribution (click map to enlarge):
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An erect raceme of 12 to 25 pinkish purple to whitish pea-like flowers, each 3/8 to 5/8 inch long on a very short hairy stalk. The upper hood is quite large and showy with white bars in the middle and base. The calyx tube is short, less than 1/8 inch with sharp triangular lobes and fine hairs. The central stalk is greenish gray from soft fine hairs and emerges from the upper leaf axils, growing up to 2½ inches long by the time fruit sets.
Leaves and stems:
Leaves are alternate and compound, 2 to 3 inches long with 11 to 25 linear to oblong leaflets that are toothless, sometimes short-stalked, often folded in along the midrib with a rounded to squared off tip, sometimes notched, with short appressed hairs on the lower surface and two leafy stipules at the base of the stalk, connected freely at the base. Multiple stems up to 20 inches long form sprawling clumps with erect tips, silvery green in color from fine appressed hairs.
Astragalus flexuosus was likely never widespread in Minnesota, which is at the very eastern edge of its range. Preferring sandy soils or rocky hilltops and bluffs, over 99% of its habitat has been destroyed by agriculture, if not crops then by grazing. Gravel mining and encroachment of red cedar, once controlled by frequent fire, also threaten it today. According to the DNR, it was listed as a Special Concern species in 1984. There are 3 varieties in North America, with var. flexuosus found in Minnesota.
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Photos courtesy Peter M. Dziuk taken in Chippewa County.
Have you seen this plant in Minnesota, or have any other comments about it?