Great River Bluff St Park 6-2005 - dogs-at-work
White camas 
http://www.dnr.state.mn.us/wildflowers/whitecamas.html 

White camas (Zigadenus elegans)  
 
Poisonous perennial, about 3 feet tall. Member of the Lily Family found in wet prairies. Tall panicle of white flowers that open in early July and include 6 tepals (sepals and petals that look alike). Leaves (mostly clustered around base) are long and narrow.

White camas
http://www.dnr.state.mn.us/wildflowers/whitecamas.html

White camas (Zigadenus elegans)

Poisonous perennial, about 3 feet tall. Member of the Lily Family found in wet prairies. Tall panicle of white flowers that open in early July and include 6 tepals (sepals and petals that look alike). Leaves (mostly clustered around base) are long and narrow.