| Bastardiastrum incanum (Brandegee) Bates, 1978 |
| Bastardiastrum tarasoides Fryxell, 1988 |
| Bastardiastrum tricarpellatum (B.L. Rob. & Greenm.) D.M. Bates, 1978 |
| Bastardiastrum wissaduloides (Baker f.) D.M. Bates, 1978 |
| Batesimalva Fryxell, 1975 |
| Batesimalva lobata Villarreal & Fryxell, 1990 |
| Batesimalva pulchella Fryxell, 1975 |
| Batesimalva violacea (Rose) Fryxell, 1976 |
| Beloere Shuttlew. ex A. Gray, 1852 |
| Beloere cistiflora Shuttlew. ex A. Gray, 1852 |
| Beloere crispa (L.) Shuttlew. ex A. Gray, 1852 |
| Belotia A. Rich., 1842 |
| Belotia galeottii Turcz., 1846 |
| Belotia grewiifolia A. Rich., 1845 |
| Belotia lessertiana Hochr., 1914 |
| Belotia mexicana (DC.) K. Schum., 1890 |
| Belotia reticulata Sprague, 1921 |
| Belotia tabascana Sprague, 1921 |
| Bernoullia Oliv., 1873 |
| Bernoullia flammea Oliv., 1873 |