Blue Curls is also known as Bastard Pennyroyal.

Plant is a hairy annual with a taproot. Preferred habitat is sandy pine woods, rocky woods and old fields. Distribution is throughout the Escambia region.

Leaves are opposite on the stem; widest at the center to several times longer than broad; no teeth or lobes but occasionally with have a few scattered teeth. Leaf base is wedge-shaped or sometimes graduating to a narrow point.

Flowers are at end of stems; solitary. Calyx has two lips; corolla is blue to violet; often spotted with purple; four stamens; long and curled. Flowers occur in late summer.

Fruit is an ovary with two or more seed chambers.

A related species, T. Canadensis, has yellow flowers.