| Lobelia splendens var. ignea Hook., 1857 |
| Lobelia standleyi McVaugh, 1943 |
| Lobelia stenodonta (Fernald) McVaugh, 1940 |
| Lobelia stolonifera Donn. Sm., 1899 |
| Lobelia stricta M. Martens & Galeotti, 1842 |
| Lobelia sublibera S. Watson, 1890 |
| Lobelia subnuda Benth., 1840 |
| Lobelia subscaposa Rzed., 2016 |
| Lobelia tarsophora Seaton ex Greenm., 1898 |
| Lobelia tatea (E. Wimm.) E. Wimm., 1956 |
| Lobelia trivialis E. Wimm., 1935 |
| Lobelia tuerckheimii Vatke ex B.L. Rob., 1891 |
| Lobelia umbellifera McVaugh, 1940 |
| Lobelia urticifolia E. Wimm., 1926 |
| Lobelia velutina M. Martens & Galeotti, 1842 |
| Lobelia villaregalis T.J. Ayers, 1987 |
| Lobelia virescens Benth., 1841 |
| Lobelia volcanica T.J. Ayers, 1990 |
| Lobelia xalapensis Kunth, 1819 |
| Lobelia yucatana E. Wimm., 1935 |