is a widespread and variable species, in such aspects as height, number of leaflets, flower length and seedpod curvature; five varieties are recognized, of which two are common (var castoreus, var newberryi). The leaflets are quite distinctive, being rather larger and fewer in number than for many similar species - up to 0.8 inches long, numbering 3 to 15. Leaflet tips may be notched or entire, pointed or rounded. Leaves, calyces and stems have a covering of long, silky hairs.
Flowers form in groups of between 3 and 8, at the tip of upright stalks. Buds are creamy white, while the petal color ranges from white to pinkish purple. Colored banner petals have a whitish patch at the center, and all such petals are crossed by a few vertical pink veins, most strongly towards the base. The banner petal is curved back by about 40 degrees. The reddish calyx has a covering of hairs; mostly white, some darker. Seed pods are inflated, about one inch long, and densely covered by white hairs.