Showy flowers from violet to purple-blue, grow from leaf axils. I measured a flower at 25 mm long and 22 mm wide. Leaves are opposite, sessile, oblong-lanceolate, serrate. Plants are glabrous and have square stems. Begin flowering mid to late July.
Habitat is river shoals and steam banks in the Boreal forest.
Height is listed in Budd's Flora to 100 cm. We measured plants to 45 cm tall.
This plant is very rare, listed as an S1 by the Saskatchewan Conservation Data Centre.
The above photos were along the Red Deer River, July 13th and August 6th, about 400 km north east of our home in Regina, SK.