This section is from the "The Herb Hunters Guide" book, by A. F. Sievers. Also available from Amazon: Herb Hunters Guide.

Figure 26.Boneset (Eupatorium perfoliatum)
Eupatorium connatum Michx.
Thoroughwort, thorough-stem, thoroughwax, wood boneset, teasel, agueweed, feverwort, sweating plant, crosswort, vegetable antimony Indian sage, wild sage, tearal, wild isaac.
Boneset is a common weed in low, wet ground, along streams, on the edges of swamps, and in thickets from Canada to Florida and west to Texas and Nebraska.
This plant is easily recognized by the peculiar arrangement of the leaves, which are opposite each other and joined at the base, making it appear as though they were one with the stem passing through the center. It is erect, growing rather tall, from 1 to 5 feet in height, with rough, hairy, stout stems. The crowded, flat-topped clusters of flowers are produced from about July to September and consist of small heads of tubular white flowers.
The leaves and flowering tops, collected when the plants are in flower, and stripped from the stalk.
 
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