Osmundaceae

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Osmundaceae A family of eusporangiate ferns of primitive type and ancient ancestry. The sporangia, all developing together, are massive and short-stalked and have a group of thick-walled cells at their apices, instead of a ring (annulus) of thickened cells as in more modern ferns. There are 3 genera, with about 18 species, found throughout most of the world.