Sp. Pl. 2: 1063. 1753; Gen. Pl. ed. 5, 484, 1754.

Etymology: Saxon, Osmunder, name for Thor, god of war
Treatment appears in FNA Volume 2.

Plants terrestrial. Stems creeping; tips often somewhat erect. Leaves dimorphic; fertile leaves erect, often notably smaller than sterile leaves in length and width. Blades 1–2-pinnate; pinnae monomorphic to dimorphic, pinnatifid or pinnate.


Nearly worldwide, tropical and temperate regions.


Species 10 (3 in the flora).

Selected References



1 Fertile leaves with pinnae monomorphic, all spore-bearing; tuft of hairs persistent on abaxial surface of pinnae near base. Osmunda cinnamomea
1 Fertile leaves with pinnae dimorphic, some spore-bearing, some not; tuft of hairs absent on abaxial surface of pinnae near base. > 2
2 Sterile leaves 2-pinnate with pinnules sessile. Osmunda ruggii
2 Sterile leaves pinnate-pinnatifid or 2-pinnate with pinnules stalked. > 3
3 Fertile pinnae apical, sterile leaves 2-pinnate. Osmunda regalis var. spectabilis
3 Fertile pinnae medial, sterile leaves pinnate-pinnatifid. Osmunda claytoniana