Canada anemone, on the TCT this morning, in Ottawa:
White flowers with 5 petal-like sepals (occasionally 6).
A distinctive green central seed head surrounded by many yellowish stamens.
Deeply divided, toothed leaves.
Growing in a large spreading patch rather than as isolated plants.
Blooming in early summer.

A few interesting facts:
Native throughout much of Canada.
Spreads aggressively by underground rhizomes and can form extensive colonies.
Excellent for pollinators.
Not usually browsed heavily by deer.
Can become a vigorous groundcover in moist soils.

I was quite happy to find out that this flower has a distinctive Canadian name! #wildflowers