Crested wood fern

IUCN Red List

LC - Least Concern

NatureServe

N5 - Secure
SNR - Unranked

Minnesota

not listed

Great Plains

OBL - Obligate wetland

Midwest

OBL - Obligate wetland

Northcentral & Northeast

OBL - Obligate wetland

Crested wood fern is a common, easily identified, medium-sized fern. It occurs in Europe, northwestern Asia, and North America. In the United States it occurs from Maine to South Carolina, west to Minnesota, Iowa, and Tennessee, and there is a disjunct (geographically separate) population in the foothills of the Rocky Mountains in northeast Washington, northern Idaho, and northwest Montana. It occurs throughout southern Canada.

Crested wood fern is found in a variety of wet habitats with rich soil, including swampy deciduous woodlands, coniferous swamps and bogs, and open shrubby wetlands.

Crested wood fern rises on several closely spaced or clustered leaves (fronds) from an erect to prostrate and short-creeping underground stem (rhizome). There is usually a rosette of cluster of overwintering sterile fronds along with several fertile fronds.

The fronds are 14″ to 28″ (35 to 70 cm) long and 3″ to 4¾″ (8 to 12 cm) wide. They are pinnate-pinnatifid, meaning that they are once cut into separate leaflets (pinnae), and those pinnae are only lobed, not cut into separate units. This gives the frond a sturdy rather than a lacy appearance.

The frond stalk (petiole) is one-third to one-quarter the length of the leaf, and it is scaly, at least near the base. The scales on the petiole and the rhizome are tan, linear to egg-shaped, and a single color (concolorous). They are not shiny.

The fertile frond is tall, narrow, and stiffly erect. The blade is narrowly lance shaped or with almost parallel sides (linear), widest at or above the middle, and tapered gradually to the base. It is pinnately compound, divided into 10 to 20 pairs of pinnae. The overall shape of the frond is said to resemble a rooster’s comb or crest—the inspiration for both the common name and the species epithet, cristata. The central axis (rachis) is green, stout, and slightly scaly toward the bottom.

The sterile frond is spreading, broader, triangular, and shorter, one-half to three-quarters the length of the fertile frond. It remains green through the winter.

The pinnae are ¾″ to 3½″ (2 to 9 cm) long and vary from triangular to linear. Lower pinnae on fertile fronds are triangular, widely spaced, and often louvered, twisted 90° like an opened Venetian blind. They become gradually less triangular and less widely spaced approaching the tip. They are cut into 6 or more pairs of blunt lobes. The lowest lobe of the lowest pinna is the same length as the opposite lobe and is slightly longer than the next lobe.

The reproductive structures are born on the underside of the lobes. There are 1 to 6 round clusters (sori) of spore-bearing cases (sporangia) arranged halfway between the midvein and the margin of each lobe. Each sorus is covered with a thin, kidney-shaped, protective veil (indusium). The indusium is pale white or tan and clearly visible at first, but it is usually shriveled at maturity.

Height

14″ to 28″ (35 to 70 cm)

Similar Species

Swampy deciduous woodlands, coniferous swamps and bogs, and open shrubby wetlands

Sporulation

June to September

Pests and Diseases