Eupatorium serotinum

Eupatorium serotinum is similar to E. semiserratum but has a petiole that is 2 cm or more long, while E. semiserratum has a petiole that is less than 2 mm long or absent. It is also similar to Ageratina altissima which has a short petiole, 20 flowers per head, phyllaries in 2 series and no glands, while Eupatorium serotinum also has 11 flowers per head, phyllaries in 3 or more series, and resinous glands. A. altissima is also lower growing and has bright white flowers while E. serotimum has dirty gray flowers. Similar to E. rugosum but has a purple stem. Opposite leaves, 12-15 teeth on each side of leaf. Petiole longer than 5 mm. Upper leaves sometimes alternate or just scattered.

The seeds of several Eupatoriums are eaten by birds.

Found frequently in open places throughout Louisiana and southeast and north-central Texas. It ranges throughout the southeastern United States and Mexico. The species in this genus had many medicinal uses by early pioneers. Their leaves were used as a poultice under splints to heal broken bones, which explains the origin of its common name, "boneset."

Old fields, waste ground, and railroad embankments, open moist woods in bottomlands.