| Abbreviation | Definition |
|---|---|
| PGU | Plant Growth Unit |
| PH | Plant Hygrophelia |
| PHM | Pink Hibiscus Mealybug |
| PHWI | Phlyctis Willeyi (plant) |
| PHWO | PHiladelphus WOotonii Hu (Wooton's Mock Orange - plant) |
| PI | Plant Introduction |
| PJM | P.J. Mezitt |
| PK | Pure Kush |
| PL | Potato Leaf |
| PL | Preliminary Leaf |
| PLO | Plant Liberation Organization |
| PLRV | Potato Leafroll Virus |
| PMB | Paul Martin Brown, botanist |
| PMG | Pest Management Guide |
| PMP | Program in Molecular Plant Biology |
| PNP | Plant Names Project |
| PPAF | Plant Patent Applied For |
| PPFD | Photosynthetic Photon Flux Density |
| PPMIS | Plant Pest Management Information System |
| PPQ | Plant Protection and Quarantine |