This lifeform is found widely in Eurasia. This lifeform is widespread in North America. This lifeform is common in suitable environments.

Marsh fern or marsh shield-fern (Dryopteris thelypteris to Thelypteris palustris) is found in marshes and wet woods from New Brunswick west to Manitoba, and south to Florida, Louisiana, and Texas.  This species is also found in Eurasia.  The leaves can be up to 30 inches long and six inches wide.  The sori are crowded

Marsh ferns (Thelypteridaceae) are essentially a tropical family with about 900 species. There is no universal agreement on the generic division of this family. The Thelypteridaceae family, per Kartesz, is represented by five genera and 63 species in North America, including Greenland, Hawaii, Puerto Rico, and the Virgin Islands.

Order Eufilicales contains most of the ferns seen in the woodlands in North America. There is some discussion as to the proper division of this order into families. Previoulsy in this reference, all ferns were grouped into a single family. We have recently begun the task of moving various ferns to a more modern family organization.

Ferns (Class Filicinae) are normally divided into four different orders.

Fern Phylum (Pteridophyta) is a large group of primarily tropical plants that typically reproduce by a complicated process involving spores. There are typically two different generations involved in the reproductive process.

Although Ferns have vascular tissue, they are separated from the seed plants in that ferns grow directly from the fertilized zygote. There are probably over 9,000 species in this group worldwide. In prehistoric times, this phylum was the predominant plant phylum on earth. Most of the coal and oil used for energy today derives from this phylum.

Although they are still numerous in moist areas, ferns have generally been replaced by seed plants. Most ferns are small to medium-sized plants. However, there are tree ferns in the tropics.

The Fern phylum is divided into several classes including:
horsetails - Class Articulate or Class Equisetinae
Club Mosses - Class Lycopodiinae
Psilotes - Psilotinae Class
Quillworts - Class Isoetinae
Ferns - Class Filicinae

The first four classes are very primitive when compared to the last or fern class. Some authors have suggested that the fern class is more closely related to the seed plants than the first four classes.

Kartesz finds 27 different families in the Pteridophyta. He finds 893 full species growing in greater North America, including Hawaii, Puerto Rico, the Virgin Islands, and Greenland.

Plant kingdom contains a large variety of different organisms including mosses, ferns, and seed plants. Most plants manufacture their energy from sunlight and water. Identification of many species is difficult in that most individual plants have characteristics that have variables based on soil moisture, soil chemistry, and sunlight.

Because of the difficulty in learning and identifying different plant groups, specialists have emerged that study only a limited group of plants. These specialists revise the taxonomy and give us detailed descriptions and ranges of the various species.  Their results are published in technical journals and written with highly specialized words that apply to a specific group.

On the other hand, there are the nature publishers. These people and companies undertake the challenging task of trying to provide easy to use pictures and descriptions to identify those species.