Trema lamarckianum, Lamarck's trema, West Indian nettle tree, or pain-in-the-back is a plant species in the genus Trema of the family Cannabaceae. It is a small evergreen shrub that is native of Florida and the West Indies. It has several common names such as pain-in-back, cabrilla and Lamarck trema. It is 6 m tall growing all year.

Trema is a genus of about 15 species of evergreen trees closely related to the hackberries (Celtis), occurring in subtropical and tropical regions of southern Asia, northern Australasia, Africa, South and Central America, and parts of North America. They are generally small trees, reaching 10–20 m (33–66 ft) tall.