Pennsylvania cudweed 
Pentaphragma begoniaefolium 
Perennial Sunflower 
Perezia magellanica 
Pericallis cruenta 
Phagnalon barbeyanum 
Phagnalon graecum 
Phagnalon nitidum 
Philadelphia fleabane 
Picris asplenioides 
Picris cyanocarpa 
Picris strigosa 
Pineappleweed 
Pink and white everlasting 
Pink Hawk's-Beard 
Pink Thoroughwort 
Pinnate goodenia 
Pinnate prairie coneflower 
Plain treasureflower 
Plains coreopsis 
Platycodon 
Pliant Lettuce 
Polychrysum 
Pompom weed