See text Osmunda is a genus of primarily temperate-zone ferns of family Osmundaceae.

Smith et al. (2006), who carried out the first higher-level pteridophyte classification published in the molecular phylogenetic era, described three genera in that family, namely Osmunda, Leptopteris, and Todea.

A common theory is that Osmunda derives from Osmunder, a Saxon name for the god Thor.

[9] Other explanations propose that it is from Middle English and Middle French words for a type of fern, or mention an English folk tale of a boatman named Osmund hiding his wife and children in a patch of royal fern during the Danish invasion.

One of the species, the cinnamon fern (Osmundastrum cinnamomeum) forms huge clonal colonies in swamp areas.