Flower:

Round flower heads 3/8 to ½ inch across, single at the tips of long stalks at the top of the plant and arising from the upper leaf axils. Flower heads are made up of about 50 tiny, greenish white flowers, each with 5 petals (magnification may be needed), a single style, and 5 long white stamens with pale yellow tips. Stalks are angled, smooth to sparsely hairy, green, and ¾ to 2½ inches long.

Leaves and stems:

Leaves are alternate, twice compound, 2 to 4 inches long, very feathery with 6 to 14 oblong branches, each up to 1½ inches long and with 20 to 30 pairs of leaflets. Leaflets are about 1/8 inch long, lance-oblong with a fringe of short hairs around the edge. Leaf stalks are finely hairy. Stems are erect, few branched, grooved, and hairless to sparsely hairy.

Fruit:

Fruit is a pea-like pod about ½ inch long, curved, flattened, the pods arranged in a spiral around the head. Pods dry to brown and split along the top seam, releasing 2 to 5 shiny, flattened, reddish-brown seeds.

Notes:

Prairie Mimosa is an uncommon plant that reaches the northern edge of its range in Minnesota. According to the DNR, it was likely much more common before virtually all the prairie in the state was converted to agriculture. Though it is found in assorted habitats in other parts of its range, in MN it is now found primarily along lake shores that are somewhat protected from the plow, often in sandy soil. It was listed as a Special Concern species in 1984. An attractive species, the feathery foliage, small round flower heads, and fruit clusters make it easy to identify. It is available in the native plant trade and does well in a sunny garden with loamy or sandy soil.