Osmunda cinnamonea is a type of fern that is known for its cinnamon-colored spore cases. It is also commonly referred to as cinnamon fern. However, there are a few other synonyms that can be used interchangeably with this species, such as royal fern, interruptedly-branched fern, and flowering fern. These terms describe different aspects of Osmunda cinnamonea, such as its regal appearance or unique branching habit. Regardless of which synonym is used, this fern is a popular choice for gardeners and naturalists alike due to its ornamental value and ecological importance.