This section is from the book "Who's Who Among The Wild Flowers", by W. I. Beecroft. Also available from Amazon: A Field Guide to Edible Wild Plants.
Ague-weed: Indian Sage. Eupatorium perfoliatum.
Composite Family. July - Sept.
Found in low, wet ground. From Nebraska, Manitoba, New Brunswick, south to the Gulf of Mexico.
Small, dull white, in large, flat-topped cluster terminating stem 2 - 5 feet high.
Opposite, often united at the base around the stem, wrinkled, toothed. Plant stem and under surface of leaves downy.

Thoroughwort.
 
Continue to: