Lithospermum is a genus of plants belonging to the family Boraginaceae. The genus is distributed nearly worldwide, but most are native to the Americas and the center of diversity is in the southwestern United States and Mexico. Species are known generally as gromwells or stoneseeds. Some species, such as Lithospermum arvense, are sometimes classified in the genus Buglossoides, but that genus is subsumed into Lithospermum by works such as the Flora of China. In addition, a 2010 molecular study showed that the genus Onosmodium should be included within Lithospermum.