Flower:

A cluster of stalked, bi-color flowers at the tip of the stem, sometimes also at branch tips. Flowers are ½ to ¾ inch wide and have a creamy yellow colored erect hood (the standard) with two pink, rudder shaped lateral petals (the wings) that loosely drape along side the lower lip (keel) that is a lighter yellowish pink. The outer surface of the upper standard, calyx and flower stalks are densely covered with fine hairs.

Leaves and stem:

Leaves are compound in groups of 15 to 31. Leaflets are oval elliptic to lance elliptic with pointed tips, ½ to 1 inch long, to 3/8 inch wide, finely hairy on the underside especially along the midrib, silky hairy to hairless on the upper surface, and have a minute stalk. Leaflet color is green to gray-green.

At the base of a compound leaf is a pair of appendages (stipules) that are linear to narrowly triangular with a long taper to a pointed tip. Stems are densely hairy and few branched, with multiple stems from a single crown.

Fruit:

Fruit is a pod 1½ to 3 inches long, slightly flattened, maturing from green to brown, and densely covered in silky hairs that can give it a gray cast.

Notes:

Goat's-rue is restricted to Minnesota's southeast counties, preferring acidic, open sandy prairie soils with sparse tree cover present. Dry site adapted invasive species such as spotted knapweed and leafy spurge present constant concerns for species such as this with already diminished populations from habitat lose to agriculture and over grazing. According to the DNR, it was designated a State Special Concern species in 1984. It does not do well as a garden plant due to its specific soil requirements. Factoid: Back in the days before binomial nomenclature (2-word genus-species Latin names) came into being, a species scientific name might have been several words long, to be as descriptive as possible. In the 1800s naturalist Charles Pickering referred to Goat's-rue as Cicer astragaloides virginianus hirsutie pubescens floribus amplis subrubentibus. Say that 3 times fast :-)

The leaves resemble those of many other members of the pea family, such as Astragalus or Vicia, both of which have flower and fruit clusters on stalks arising from the leaf axils, where Tephrosia are all at stem tips. The size and shape of fruits are different for each of these, with Tephrosia more long and slender like a string bean, Astragalus and Vicia tending to be shorter and broader. The shape of stipules is also usually unique for each species. Vicia is also vining with tendrils, which Tephrosia lacks.