Lobelia, a genus of about 375 species of annual and perennial plants that grow in temperate and tropical areas north and south of the Equator. Lobelia flowers have two lips, of which the upper is divided into two lobes, and the lower into three. Each flower has a long nectar tube. Many species of lobelia are grown in gardens.

The cardinal flower grows from two to five feet (60 to 150 cm) tall in low, wet areas of North America. Its bright scarlet flowers are pollinated chiefly by hummingbirds. Indian tobacco is a small annual plant with blue flowers. Lobeline, a drug obtained from the plant, was once used as an emetic and to relieve spasms and clear the lungs of phlegm.

The genus Lobelia is of the bluebell family, Campanulaceae. The cardinal flower is L. cardinalis; Indian tobacco, L. inftata; edging lobelia, L. Erinus.