     Paxistima, Canby - Paxistima (Pachistima) canbyi
Pear, Ussurian - Pyrus ussuriensis
Pine, Bristlecone - Pinus aristata
Pine, Eastern White - Pinus strobus 
Pine, Jack - Pinus banksiana
Pine, Limber - Pinus flexilis
Pine, Mugo - Pinus mugo
Pine, Ponderosa - Pinus ponderosa
Pine, Red - Pinus resinosa 
Pine, Rocky Mountain Lodgepole - Pinus contorta var. latifolia
Pine, Scots - Pinus sylvestris
Pine, Swiss Stone - Pinus cembra
Plum, Canada - Prunus nigra
Plum, Cistena - Prunus x cistena - also Cistena Cherry or Purpleleaf Sandcherry
Plum, Double Flowering - Prunus triloba var. multiplex (cv Multiplex) 
Plum, Muckle - Prunus x nigrella cv Muckle
Plum, Wild - Prunus americana
Poison Ivy - Rhus radicans
Poplar, Balsam - Populus balsamifera
Poplar, Black Cottonwood - Populus trichocarpa
Poplar (Columnar Swedish Aspen) - Populus tremula cv Erecta
Poplar, Cottonwood - Populus deltoides
Poplar, Hybrid - Populus deltoides hybrids
Poplar, European Black - Populus nigra
Poplar, Northwest - Populus x jackii cv Northwest 
Poplar, Tower - Populus x canescens cv Tower - also Tower Aspen
Poplar (Trembling Aspen) - Populus tremuloides - also Quaking Aspen
Poplar, White - Populus alba - also Silver Poplar 
Potentilla, Shrubby - Potentilla fruticosa - also Shrubby Cinquefoil
Prinsepia, Cherry - Prinsepia sinensis


