15 cm ruler for scale

Branching annual or biennial plant with a dense flower spikes at stem tips and clusters in leaf axils. Flowers are white to purple-blue, small - measured to 3 mm diameter. Calyx is spiny making the flower clusters prickly. Leaves lanceoate, toothed, opposite, leaf highlighted in above photo was 5 cm long (including petiole) and 1 cm wide. Stems square, pubescent. Leaf bottoms have very short hairs, there are hairs on leaf margins, top of leaves are glabrous.

Budd's Flora describes this as not generally common, locally abundant. Found in disturbed soil in forest clearings.

Height is listed to 50 cm, we measured plants to 70 cm tall.

Took the above photos on August 1st, disturbed soil near a forest cabin, Meadow Lake Provincial Forest, about 500 km north west of our home in Regina, SK.