Thelypteris Dryopteris is a fern species commonly known as the marsh fern or the oak fern. There are several synonyms for this species, including Dryopteris thelypteris, Polystichum thelypteris, and Phegopteris thelypteris. These synonyms are often used interchangeably depending on the context. Thelypteris Dryopteris is native to North America and is commonly found in wetlands, swamps, and other moist areas. The fern is known for its attractive foliage and is a popular choice for gardens and landscaping projects. Its versatility and beauty make it a beloved addition to any outdoor space.