Polypodium arcanum Maxon Polypodium arcanum Maxon, Proc. Biol. Soc. Washington 51: 38. 1938 sec. Mickel & Smith 2004=Polypodium deltoideum Liebm., Mexic. Bregn. 190. 1849 hom. illeg., non Sw syn. sec. Mickel & Smith 2004