Plant Family: 28 Genera in Olacaceae

Plant Family: 27 Genera in Oleaceae

Plant Family: 22 Genera in Onagraceae

Plant Family: Oncothecaceae – Genus Oncotheca

Plant Family: 11 Genera in Opiliaceae

Plant Family: 740 Gnera in Orchidaceae

Plant Family: 99 Genera in Orobanchaceae

Plant Family: 5 Genera in Oxalidaceae

Plant Family: Paeoniaceae – 42 Species in Genus Paeonia – Peonies

Plant Family: 36 Genera in Ochnaceae

Plant Family: Penthoraceae – Genus Penthorum

Plant Family: 12 Genera in Pentaphylacaceae

Plant Family: Pentaphragmataceae – Genus Pentaphragma

Plant Family: Pentadiplandraceae – Genus Pentadiplandra

Plant Family: Pennantiaceae – Genus Pennantia

Plant Family: 3 Genera in Penaeaceae

Plant Family: 11 Genera in Pedaliaceae

Plant Family: 31 Genera in Passifloraceae

Plant Family: 3 Genera in Paracryphiaceae

Plant Family: 46 Genera in Papaveraceae

Plant Family: 5 Genera in Pandanaceae

Plant Family: 3 Genera in Pandaceae

Plant Family: 3 Genera in Paulowniaceae

Plant Family: 3 Genera in Philydraceae