By Tom Koritansky, Director of Park Operations

Ferns are a fascinating group of plants. They are the second most diverse group next to seed-producing plants and have quite a long history. Ferns are found in the fossil record all the way back to the Devonian period of the Paleozoic era more than 360 million years ago—that’s older than land mammals, birds and flowering plants! Although these ancestral ferns have long gone extinct, the ferns found today still share the same basic characteristics of their ancestors. After spring ephemeral plants have bloomed and gone dormant for another year, ferns are an excellent group of plants to find throughout the summer months.  

Ferns share some of the same structures as flowering plants like roots, stems and leaves; however, they do not reproduce the same way. Flowering plants reproduce by seeds. Ferns are non-flowering and reproduce through the production of spores. Aside from their overall structure that makes them stand out compared to other plants, their unique life cycle is also worth a closer look.  

All plant life cycles involve what is known as the alternation of generations. Ferns alternate between sporophyte and gametophyte generations. The fern life cycle begins with the development of a gametophyte, which grows from a released spore. Gametophytes are small heart-shaped plants that are equipped with structures to produce both eggs and sperm (collectively known as gametes). Eggs are produced in archegonia and sperm are produced in antheridia. Gametes released by gametophyte need water in order for sperm to swim to released eggs so that they become fertilized. A zygote forms at fertilization that eventually grows into the sporophyte. The sporophyte is the generation of a fern we most often recognize.  As the sporophyte grows, spore forming structures known as sori form on fronds. Fronds are another term for fern leaves. Spores released from sori begin another gametophyte generation.

The presence of water is very important for ferns since their reproduction depends on it. Because of this necessity, ferns are often found in moist environments where water is present. At Lake Metroparks, some of the best places to view ferns are along streambanks and floodplains of the Grand and Chagrin Rivers and their tributaries.

Ferns differ greatly in the size and shape of their fronds, the number of divisions of leaflets and subleaflets on a frond, and the placement of sori. On some ferns, sori are located on margins of leaflets, others on the midrib, while others may even produce separate spore-forming fronds.

We’re lucky to have quite a lot of fern diversity within the parks. Good fern diversity is often an indicator that land has gone undisturbed for some time. If you’re out in the parks this summer, take a moment to look for these ferns along the trail:

New York fern (Theylpteris noveboracensis) — Most often growing in colonies, New York fern is also noted by its lighter green color. Fronds stand about 18 inches tall and about six inches wide tapering to a point at the top and bottom. Leaflets of the fronds are stemless and never opposite of each other. A good place to see New York fern is along the trails of Hogback Ridge Park.

Christmas fern (Polystichum acrostichoides) — Known for being green at Christmas, this evergreen fern is quite abundant throughout the parks and grows in clusters. Leaves can be up to three feet tall, but relatively thin at only four inches wide. The lance-shaped leaflets feature a distinctive lobe at the base resembling a Christmas stocking. Look for Christmas fern along slopes and wooded streambanks. Both Girdled Road Reservation and Penitentiary Glen Reservation boast ample populations of Christmas fern.

Ostrich fern (Matteuccia struthiopteris) — One of the largest ferns with fronds reaching up to 60 inches tall and 14 inches wide. Leaflets are alternately placed along fronds. Smaller, fertile spore-forming fronds form separately from the larger sterile fronds. Most often found along streambanks and floodplains. Look for ostrich fern growing along the Grand River floodplain at Indian Point Park.

Maidenhair fern (Adiantum pedatum) — Uniquely divided recurving stalks from which leaflets emerge are a noticeable characteristic of maidenhair fern. Flattened fronds often grow to about 16 inches long. Although this fan-shaped fern occurs more sporadically in the parks than others, it can can be found along the banks of Paine Creek.

Sensitive fern (Onclea sensiblis) — Another tall fern with fronds extending about 24 inches high. The leaves of sensitive fern are stout and course with conspicuous veins. Also found in wet and moist environments within woodlands and meadows. Sensitive fern gets its name because it wilts quickly when cut. Sensitive fern can be found in some of the wet woods and meadows of Lake Erie Bluffs.   

Royal fern (Osmunda regalis) — Widely spaced and branching leaflets are notable characteristics of royal fern. Fertile leaflets appear at the top of stems. This fern can grow to heights up to six feet depending on its environment. Look for royal fern within wetlands at Girdled Road Reservation and along the floodplain of Paine Creek at Hell Hollow Wilderness Area.