Identifying Pacific Northwest Native Ferns

Maidenhair, Sword Fern, Deer and Lady Ferns Thrive in Damp Forests

Aug 30, 2009

From tough sword ferns to delicate maidenhairs, ferns flourish on the moist, shady forest floor of temperate rainforests of Oregon, Washington and British Columbia.

Ferns are ancient plants that developed before flowering plants. A fern doesn’t produce seeds directly, but rather develops spores that grow in cases, called sori, generally appearing as dots on the backs of fertile leaves. Rows of orange-brown shield-covered sori are easily visible on the backs of the fertile fronds of sword ferns.

The spores, when released, do not develop directly into ferns, but rather grow into a tiny leaf-like structure called a prothallium. The prothallium produces eggs and sperm that unite to generate new ferns. It takes several years for a fern to grow from a spore.

The leaves and roots of ferns grow from underground rhizomes that can be extensive and live for many years. Though the leaves, or fronds, of many ferns die back in winter, the rhizome survives to sprout new fronds in spring.

In dense conifer forests, sword ferns may blanket the ground. Their tough, leathery leaves rise in a circular arrangement from the base and can grow to three or four feet in length. The dark green fronds are used extensively in flower arrangements. An abundance of sword fern fronds are collected every year for sale to the floral industry across the country. The plants are evergreen.

The soft, delicate fronds of the maidenhair circle around the tops of wiry black stems to produce round clusters in damp areas. They particularly like dripping stream banks or areas where they’re continually splashed by falling water. The edges of the thin leaflets on each frond are fringed. They are very common in Northwest forests and a favorite with native plant enthusiasts and gardeners. Fronds die back in winter.

The shiny black stems of maidenhair ferns were used in basketry by Native Americans.

This large fern is common along streams, but are plentiful wherever the forest is damp and shady. It can grow to five feet high with crisp, gracefully arching fronds. It’s best identified by the shape of its fronds: widest at the center and tapering toward both the top at bottom. The lady fern is prettiest in spring and dies back in winter.

The fertile and non-fertile fronds are deer fern are distinctive. The fertile (spore-bearing) fronds are long and narrow, standing erect. The slender non-spore-bearing fronds grow in shorter clusters around them. Fronds taper toward each end. They favor deep, wet forests.

Their resemblance to stalks of grain prompted the name spicant, from the Latin for a “head of grain.” Deer like to eat these ferns, hence its common name, “deer fern.”

Ferns growing on the trunks of trees of big-leaf maples are almost certainly licorice fern. They find a cushiony clump of moss on broadleaf trees, or even on rocks, to take root. They’re crisp and attractive, smaller than most ground ferns and with fewer leaves. The rhizome buries itself in thick moss to obtain moisture. They are evergreen, but in dry weather, the leaves wither, only to reappear when the rain comes.

The spore-bearing sori of the licorice fern are large and easy to see in rows along the leaflets.

Bracken is seemingly everywhere, spreading across open clearings and fields. Unlike other ferns here, it survives dry conditions. Bracken is widespread in the northern hemisphere. Its rhizomes reach deep into the ground, storing food and continually sending up new shoots. It’s difficult to remove from spots where it’s not wanted.

Fronds are triangular shaped, made up of linearly triangular leaflets that divide again into individual sub-leaflets. They grow in clusters that can be up to five feet high.

Ferns are as much a part of Pacific Northwest woods as conifer trees, carpeting the shady forest floor with green.

Sources:

National Audubon Society Field Guide to the Pacific Northwest, by Peter Alden and Dennis Paulson, Chanticleer Press, Inc., N.Y., 1998.

Ferns to Know in Oregon, by Charles R. Ross, Oregon State University Extension Service, Corvallis, OR, 1983.

The copyright of the article Identifying Pacific Northwest Native Ferns in Plant Species is owned by Linda McDonnell. Permission to republish Identifying Pacific Northwest Native Ferns in print or online must be granted by the author in writing.