Stout biennial plant, erect, single stemmed, to several stems from the crown of the plant. Very showy, large white flowers to 12 cm in diameter, fragrant. Flowers appear mid July, and begin to open after 8:00 p.m. Leaves are alternate, lanceolate, deeply toothed, and rough to touch. Leaves to12 cm long and 2 cm wide.
Habitat is clay hillsides along the southern edge of Saskatchewan. Budd's Flora describes as plentiful locally, but not common.
Height is listed to 60 cm in Budd's Flora, the plants we observed were 30 - 40 cm tall.
The above photos were taken July 24th and August 3rd, on the clay cliffs of the Frenchman River valley near Eastend, about 400 km SW of our home in Regina, SK.