Pot marigold 
Prairie fleabane 
Prickly Lettuce 
Prickly sow-thistle 
Pseudopodospermum libanoticum 
Pterocephalus sanctus 
Pulicaria auranitica 
Pulicaria glutinosa 
Pulicaria incisa 
Pulicaria undulata 
Purple Burr-daisy 
Purple Coneflower 
Purple fan-flower 
Purple milk thistle 
Purple salsify 
Purple Star-Thistle 
Purplestem aster 
Racemose pussytoes 
Rampion Bellflower 
Rattlesnakeweed 
Rayless chamomile 
Rayless Sunflower 
Red Dahlia 
Red Everlasting