They have white umbrella-shaped flower, the stem is hollow. It grows near maple trees. This was about 3 to 4 feet high. Smells like celery. Please advise and thank you for your help. Found near Michigan/Ontario border. pictures attached.
Possibly Heracleum maximum. See.... http://fireflyforest.net/firefly/2006/08/18/common-cowparsnip/ http://plants.usda.gov/java/profile?symbol=HEMA80
