The woody trunk of the tree is equipped with irregular and thorny branches and can reach 50 cm in circumference.

The corolla, like that of other legumes like common beans, is butterfly-shaped; however, the largest petal, called the "standard", is arranged in the lower part.

The remaining two petals partially fuse together on occasion and form the flower's keel or "carina"; this protects its reproductive organs.

The tree's fruit is a legume, a dry pod a few centimeters in length derived from a single carpel and contains about 8–10 chestnut-brown bean-shaped seeds.

In cultivation in the United Kingdom this plant has gained the Royal Horticultural Society's Award of Garden Merit.

It is distributed throughout northeastern and central western Argentina, eastern Bolivia, southern Brazil, much of Paraguay, and almost all of Uruguay.