It is native to the Americas, and is known on other continents as an introduced species and a common weed.

It can be weedy in its native range as well, growing on roadsides, on fields, and in other disturbed habitat.

The two subspecies are defined generally on the basis of hairiness: ssp.

The plant produces erect stems up to about 30 centimeters tall.

The inflorescence is a loose terminal raceme of flowers and lance-shaped bracts.