Nature on Trail: Ferns

By  Janice Van Cleve

As we trudge miles through the woods on our way to summits, we often overlook the beauties of the understory. Common ferns (polypodiaceae) are an important and ancient part of the lush greenery that abounds in our forests.
Ferns are indeed ancient. The fossil record from 500 million years ago shows they are one of the first vascular plants—that is, plants that have specialized stiff tissues for holding leaves aloft and for transporting water and nutrients. They were the dominant plants on earth during the Carboniferous Period and a main source of today’s coal. Currently over 10,000 species have been identified, and just over 30 occur in the Cascades and Olympics.

There are many ways to slice and dice the fern family. One is by habitat. Many of our ferns like the moist, damp, shady woods and these tend to grow the biggest. Others, however, prefer rocky habitats and can be found even up above timberline in talus fields. One of my favorite places to appreciate ferns is in the rainforest between Little Si and Big Si when the overcast sky casts a hushed gray pall over their drippy green fronds. Another good place is on the east slopes of Tiger Mountain.

Licorice ferns are known to grow on the trunks of maple trees. Photo by Emma Cassidy.

Another way to distinguish ferns is by leaf pattern. Some ferns have branches with feathery, compound leaves paired along each branch. Two of the most common around here are the Pacific oak fern, found in shady, rocky places and the common bracken, which likes sunshine and is one of the plants most aggressive in reclaiming clearcut or burned-out spaces. Bracken can be particularly dense in high altitude meadows. It was up to my shoulders on the Bare Mountain Trail and very thick on the way up to Marmot Lake.

Other ferns have either compound or simple leaves growing right out of the main stem. The common sword fern is a good example of this. Each lobe looks like a sword wielded by the Uruk Hai (one of Saruman’s well-armed orcs in the Lord of the Rings). One of my favorite ferns is the graceful deer fern. This one has lobed leaves that don’t quite end at the stem before the next one begins, forming a wavy line. The shape of a deer fern frond starts small at the base, gradually widening into a gentle blade, and then returns to a point.

The rough and hearty ferns that grow among rocks sometimes don’t look like ferns at all. The rock brake and Brewer’s cliff brake are short, about 6 to 8 inches high, with leaves and stems not at all feathery. These are found in Eastern Washington along the Columbia Gorge. In contrast, the Aleutian maidenhair fern can reach up to 28 inches tall. Its leaves, lobed on only one side, are found on branches in rows of two. They remind me of a line of crows flying to the branch—except that they’re green, of course.

The Field Guide to the Cascade and Olympics published by The Mountaineers Books is a reasonable guide to some of the more common ferns—but because it’s an all-inclusive field guide, its selection of ferns is limited. I’ve heard that tender fiddlehead fern sprouts are edible, but all ferns contain some carcinogenic compounds, especially the common bracken. I’ll stick to mushrooms!