The stem is wandlike. The flowers are blue, violet, or white and are wide-open, bell-shaped with 5 spreading lobes. The blooms are tucked singly in axils of roundish, clasping leaves. The base (calyx) of the blossom resembles a mirror handle and is the source of its common name. It grows to a height of 6 to 30 inches. It is found mainly in sterile fields and clearings. It blooms between May and August.

Sources:
"A Field Guide to Wildflowers, Northeastern and North-central North America" by Roger Tory Peterson and Margaret McKenny
Encyclopaedia Britannica, Volume 23

Photo taken beside my house