• Onychium Blume, 1825 accepted as Dendrobium O. Swartz, 1799 [Family: Orchidaceae]
• Onychium Kaulfuss, 1820 [Family: Pteridaceae]
• Onychium Reinwardt, 1825 accepted as Lecanopteris Reinwardt, 1825 [Family: Polypodiaceae]
• Onychium densum Brack. accepted as Aspidotis densa (Brack.) Lellinger
• Onychium strictum auct. non Kunze accepted as Anopteris hexagona (L.) C. Christens.
• Onychiumsporites Hu †