Canadian Fleabane is a tall annual of waste ground, with very small flowers in loose clusters. The lilac ray florets are very short. The stem is covered in bristly hairs.
It is similar to Guernsey Fleabane, which is hairier, has lighter-coloured leaves and no ray florets.

Flower, showing short lilac ray florets, and bristly hairs on stem		Seeds		Leaves and hairy stem