This plant is slightly furry with purple leaves which appear fused together around the stem. It grows in low wet areas. (I shot this from the boardwalk at Lake Waban.) It’s in the sunflower family! Native people used it to break fevers by heavy sweating, and it was a very commonly used medicinal plant in the 19th century for all kinds of ailments. The latin name perfoliatum comes from the way the stem appears to perforate the leaves. Native.
Common Boneset, Thoroughwort, Agueweed, Feverwort (Eupatorium perfoliatum)