| Haplopappus pinnatifidus Nutt., 1840 |
| Haplopappus propinquus (A. Gray) S.F. Blake, 1926 |
| Haplopappus pseudobaccharis S.F. Blake, 1950 |
| Haplopappus pulvinatus Moran, 1969 |
| Haplopappus purpusii S.F. Blake, 1926 |
| Haplopappus pyramidatus (B.L. Rob. & Greenm.) S.F. Blake, 1926 |
| Haplopappus ramulosus DC., 1836 |
| Haplopappus rigidifolius E.B. Sm., 1965 |
| Haplopappus rosaricus Moran, 1969 |
| Haplopappus sonoriensis (A. Gray) S.F. Blake, 1926 |
| Haplopappus spinulosus DC., 1836 |
| Haplopappus spinulosus subsp. scabrellus (Greene) H.M. Hall, 1928 |
| Haplopappus squarrosus Hook. & Arn., 1833 |
| Haplopappus stenolepis (H.M. Hall) Hoover, 1970 |
| Haplopappus stolonifer DC., 1836 |
| Haplopappus stoloniferus DC., 1836 |
| Haplopappus tenuilobus A. Gray, 1886 |
| Haplopappus thiniicola Rzed. & E. Ezcurra, 1986 |
| Haplopappus trianthus S.F. Blake, 1938 |
| Haplopappus venetus (Kunth) S.F. Blake, 1926 |