May 18, 2004
Common Burdock (Arctium minus)
Burdock is a biennial that forms a low-growing rosette of leaves its first year, and produces a tall stem with purple thistle-like flowers the second year. It is found throughout the continental United States except in Florida, and is classified as a "noxious weed" in Colorado and Wyoming.

People who allow their long-haired dogs to run free at Fresh Pond in the fall are probably familiar with the round burdock burrs that become entangled in the animals' fur and are next to impossible to remove.