nuttalliana or Vexibia nuttalliana
looks very much like an Oxytropis sp., with a raceme of flowers with
pointed keels. Look inside the flower, however, and you'll find the stamen filaments
are separate, while Oxytropis spp. have united stamens. Flowers sometimes
have a purple calyx. Fruits of Silky Sophora are called loments and are pods with
constrictions around the seeds. Silky Sophora is most commonly found on sandy
soils on the plains.
Compare to Oxytropis sericea, which
has united stamens and a plump fruit, held upright and without constrictions.