Eupatorium mohrii, commonly called Mohr's thoroughwort, is a herbaceous perennial plant in Asteraceae

Asteraceae

The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

 native to the southeastern coastal states of the United States, from North Carolina to Florida and Louisiana to Texas. It can also be found in the Caribbean

Caribbean

The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...

. The stems grow from 30 to over 100 cm tall and are produced from tuberous rhizomes. As with other species of Eupatorium

Eupatorium

Eupatorium is a genus of flowering plants in the aster family, Asteraceae, containing from 36 to 60 species depending on the classification system. Most are herbaceous perennial plants growing to 0.5–3 m tall. A few are shrubs. The genus is native to temperate regions of the Northern Hemisphere....

, the inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

s contain a large number of white flower heads with disc florets and no ray florets. It forms hybrids with Eupatorium serotinum

Eupatorium serotinum

Eupatorium serotinum, also known as late boneset or late thoroughwort, is a fall-blooming herbaceous plant native to North America...

and Eupatorium rotundifolium

Eupatorium rotundifolium

Eupatorium rotundifolium, commonly called Roundleaf thoroughwort, is a herbaceous perennial plant in Asteraceae native to the eastern states of the United States in an area from New Jersey to Oklahoma south to Texas to Florida. The stems grow from 40 to over 100 cm tall and are produced from...

.

E. mohrii grows in moist areas, edges of ponds, and sandy soils.