Some Cool Ferns

During the warmer months of the year, ferns are common plants of the forest floor. Some of the most common ferns in this area are hay-scented fern (Dennstaedtia punctilobula), the wood ferns (Dryopteris), and bracken fern (Pteridium aquilinum), however, there is a large variety of less common and fascinating fern species that inhabit our woods and meadows.

Sensitive fern (Onoclea sensibilis) is a easily recognizable fern of damp or wet areas. This species often grows in wet, wooded areas or along forest edges. Many areas where this fern grows many not appear wet at first, but a closer examination under the soil will show that the area is indeed wet enough to support a group of these ferns. Many ferns are characterized by their divided leaves and branching vein system. Sensitive ferns are different in these respects, as the fronds only have several large divisions and contain a "netted" vein system.


Climbing fern, also known as Hartford fern (Lygodium palmatum), is a truly exciting species to find. If a casual observer passed this plant in a wet meadow, they would not realize that it is a fern. The palmate leaves and vine-like growth make this plant unlike any other fern in the region. Much like the sensitive fern, climbing fern needs a certain amount of moisture in the soil in order to survive. However, climbing fern is no where near as frequently encountered as sensitive fern. This species is listed as rare in Pennsylvania, as it is found in relatively few locations around the state. Despite being considered relatively rare, where climbing fern does occur, it often grows in large patches covering acres of ground. Climbing fern also has an interesting history, as it was the first plant in the United States to have a protection law. These vine-like plants were once collected for decorations, causing the populations to significantly decrease, which resulted in a Connecticut law banning the collection of this species.

Although it may look like many other ferns, rattlesnake fern (Botrychium virginianum) is very different than other common forest ferns. The major distinctive feature is the fertile frond that is different than the rest of the plant. In the photo, notice the "snake rattle" that grows like a frond off the main stem (where the plant gets its name); this is the fertile frond. Many other fern species produce spores on the undersides of normal, leafy fronds, but this is not the case with rattlesnake fern. This unique fertile frond is where the spores are produced. This distinctive feature allows for easy identification of this fern. Rattlesnake ferns are common along woodland edges and in small openings in the forest.


Triangle grapefern, or triangle moonwort, (Botrychium lanceolatum) appears to be an opposite of the rattlesnake fern. Rattlesnake ferns have a large sterile frond and a relatively small fertile frond, but this grapefern has a huge fertile frond and a thin, small sterile frond. This species is much less common than rattlesnake fern and is only occasionally found in wet or damp woods.

These are just a few of the many interesting ferns that grow in the woods this time of year. The next time you are in the woods, keep an eye out for these species that are often overlooked due to the presence of more colorful and showy plants and flowers.