| Pachypodium lamerei Drake, 1899 |
| Pachystelma Brandegee, 1920 |
| Pachystelma cordatum Brandegee, 1920 |
| Parsonsiinae Benth. & Hook. f., 1876 |
| Pattalias S. Watson, 1889 |
| Pattalias angustifolius (Torr.) S. Watson, 1889 |
| Pattalias palmeri S. Watson, 1889 |
| Pattalias palustris (Pursh) Fishbein, 2017 |
| Peltastes Woodson, 1932 |
| Peltastinae Pichon ex M.E. Endress, 2014 |
| Pentalinon Voigt, 1845 |
| Pentalinon andrieuxii (Müll. Arg.) B.F. Hansen & Wunderlin, 1986 |
| Pentalinon luteum (L.) B.F. Hansen & Wunderlin, 1986 |
| Pentalinoninae Pichon ex M.E. Endress, 2014 |
| Periplocoideae R. Br. ex Endl., 1838 |
| Pherotrichis Decne., 1838 |
| Pherotrichis balbisii A. Gray, 1886 |
| Pherotrichis leptogenia B.L. Rob., 1894 |
| Pherotrichis mixtecana Brandegee, 1910 |
| Pherotrichis schaffneri A. Gray, 1886 |