Friends of Netarts Bay Watershed, Estuary, Beach, and Sea

Polystichum munitum
Sword Fern
Western North America
Family Dryopteridaceae
Native

The sword fern is the most common of our local ferns - big, showy, and evergreen. It is a forest plant found in low to middle elevations. Its fronds are lance-shaped with long alternating pinna (leaflets) attached to a scaly rachis (midrib) by narrow petiole. At the base of each pinna is a distinctive ear-like lobe called an auricle. The margin of the pinna is dentate with incurved tips.

The mechanism for the dicharge and dissemination of spores by a mature sporangium is remarkable. The spoangium consist of a hollow, rather spherical case of flattened cells enclosing the spores, commonly around 64. It is connected to the base of the sorus by a thin stalk. Arching over about two-thirds of the spoangium is a narrow row of thick-walled cells termed the annulus. Continuing along the other third of that same row to the stalk are thinner walled cells, two of which are called lip cells. The cells of the annulus can fill with water during the wet season. When the water begins to evaporate during the dry season, cohesive and even stronger adhesive forces of the water come into play. As evaporation proceeds, water inside each annulus cell adheres to its thick latteral walls, and cohesion of the water molecules resists the water from breaking apart. This results in the latteral walls pulling together, straightening the annulus and opening the sporangium by separating the lip cells. As the spoangium opens, it caries the spores along. A point is finally reached at which the tensile strength of the water inside each cell caused by the straightening of the annulus is greater than the water’s cohesive forces. The water breakes, filling the cells with water vapor. This releases the tension on the elastic radial walls of each cell causing the annulus to spring back, catapulting the spores outward an inch or two.

Pinna

Blechnum (Struthiopteris) spicant
Deer Fern
Circumpolar
Family Blechnaceae
Native

The Deer Fern is green all year. It may grow to about two feet tall and has distinctive sterile and fertile fronds. Sterile fronds are lower on the plant and spread outward. The entire base of each pinna is attached to the rachis. The fertile fronds point upward and have narrow pinnae that are sometimes rolled together from the underneath side to become tube-like. The sori are continuous along the axis of the pinna covered with continuous indusia that are attached along the margin. Deer ferns are common in our moist, coastal area.

Reproductive (upper) and vegetative (lower) fronds

Underside of reproductive frond

Drytopteris expansa
Spreading Wood Fern
Western North America, parts of Eastern Canada
Family Dryopteridaceae
Native

The Spreading Wood Fern, mostly found in moist forest, is deciduous and, along with the Lady Fern, drops its leaves in the late fall. It can grow to three feet tall. Its overall leaf shape is triangular, broadest at the base and tapering toward the tip (Compare with the Lady Fern). The leaves are tripinnate. Sori are round and covered by a round indusium.

Trinagular shape of frond

Sori

Athyrium filix-femina
Lady Fern
Throughout North America
Family Dryopteridaceae
Native

The Lady Fern is a delicate upright perennial growing mostly in damp shaded forest, but it can tolerate open sun. It has bright green fronds up to a foot wide and three feet long that are deciduous and drop off in the late fall. It often grows near and can be confused with the Spreading Wood Fern Dryopteris expansa, but the frond shapes differ. The Lady Fern frond is narrow near the base, widens at the middle, and narrows again toward the tip, giving it a lance or oval shape. It is also bipinnate. The Wood Fern frond is more triangular and tripinnate. The sori are half moon to horseshoe shaped instead of round and the indusium is long and curved and attached on one side.

Oval shape of frond

Sori

Polypodium glycyrrhiza
Licorice Fern
Coastal North America from Alaska to California
Family Polypodiaceae
Native

The licorice fern is deciduous, glorious in our moist coastal fall and winter but losing its fronds in dry summer. It does well in moist fertile soil but in our area is more often found as an epiphyte on the sides of trees and woody shrubs, usually in shade. Fronds are one to two feet long. Leaflets alternate along each side of the frond’s rachis, and each is attached along its entire base. It gets its name from its sweet, licorice-flavored rhizome, chewed by coastal tribes of Native Americans, and now countless school children on field trips.

Upper side of frond

Lower side of frond

Rhizome

Pteridium aquilinium
Bracken Fern
Throughout the United States and other parts of the world
Family Dennstaedtiaceae
Native

The Bracken Fern is the world’s most widespread fern. It is large, often more than three feet tall, bright green, with triangular, bipinnate leaves branching from an erect stalk. Its rhizomes, which are edible and were consumed by native Americans, are deep enough underground to resist the heat of forest fires. The fern appears in the spring as curled fiddleheads, growing upward and spreading their maturing leaves. They die back in the fall. The leaves are coated with minute hairs. The sori are continuous along the margins of the pinnae and do not have an indusium. Bracken ferns are common in slightly shaded areas or clearings, especially in sandy soil, either wet or dry.

Fiddlehead

Sori

Polypodium scouleri
Leather Leaf Fern, Leather Polypody
Coastal North America from British
Columbia to California
Family Polypodiaceae
Native

Then Leather Fern grows in trees, rocks, an in moist humus soils along the salt-sprayed west coast. You can find it mainly attached to shaded Sitka Spruce in our area. It is distinguished by its thick robust leaves, up to a foot or more long, with rounded ends of the pinnae. The sori are large and round, have no indusium, and are in rows near the distal end of the frond.

Upper side of frond

Sori

Adiantum pedatum
Northern Madenhair Fern,
Five-Finger Fern
Coastal North America from Alaska to
California and Eastern North America
Family Pteridaceae
Native

The Northern Maidenhair Fern has delicate spreading fronds growing from a bifurcated black wiry stipe (stalk). The five-finger common name refers to its palmate shape. The maidenhair name is from its fine, shiny stipes. Its leaves repel water, hence the generic name Adiantum which means “unwetted” in Greek. The specific name comes from looking like a bird’s foot. It is mostly deciduous, though in our area some fronds will persist through winter, and it inhabits moist vertical bluffs and rocky hillsides. The leaflets are smooth on one edge and lobed on the other. Bifurcated veins lead into each lobe. Oblong sori line the edges of the leaflets. It is not common between the capes but can be found in some shaded wet locals.

Frond

Leaflet (pinna)

Cystopteris fragilis
Fragile fern
Circumboreal
Family: Dryopteridaceae
Native

Small and delicate, this fern inhabits moist soils to dry rocky cliffs throughout the Pacific Northwest. Fronds are light green, generally less than a foot long, tapering at both ends, with only a few hairs at the base. Pinnae are irregularly toothed with branched or forked veins. The plants are rhizomatous. Sori are round, occurring on one or both sides of the pinnule, and halfway covered by a thin indusium. C. fragilis dies back in the winter.

Frond

Pinnae

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