I think this is Allium stellatum.
Also known as wild garlic but I've read the bulb is more like an onion.
Crex Sand Prairie State Natural Area, Burnett Co., WI
Allium stellatum (Autumn onion, Prairie onion) is a perennial wild onion native to North America, where it grows in rocky, sandy soil. It grows from a bulb to about 1-2 feet (30-60 cm) with tufts of leaves which die back as the scape of pink to purple flowers forms. The bulbs are strongly flavored but can be eaten.