The flowers are yellow, with 5 sepals and sub-equal petals, 10 very unequal etamins in 3 groups [3-4-3] and a style very curved upwards.

It blooms in summer and autumn and is visited by bumblebees, which are responsible for its pollination.

The fruit is a hanging indehiscent legume, cylindrical in shape (about 6 to 10 cm) full of seeds.

It is distributed, from sea level to about 200 m above sea level, in all the departments of Uruguay; in southern Brazil in the states of Rio Grande do Sul and Santa Catarina; in Paraguay; and in eastern Argentina, in the provinces of La Pampa, Córdoba, Santa Fe, Misiones, Corrientes, Entre Ríos, and Buenos Aires, reaching as far south as the outskirts of Mar del Plata.

It has been introduced in Alabama, Canary Island, Cape Provinces, Florida, Georgia, India, Iraq, Italy, KwaZulu-Natal, Louisiana, Mississippi, Northern Provinces, Pakistan, South Carolina, Spain and Texas.