[Click on species name to see its detail page]
Family – Dryopteridaceae
by Lauren Ebbecke
The wood ferns, genus Dryopteris, are among the most abundant ferns in Wisconsin. Distinguish the genus is relatively easy,however, distinguishing the specific species is somewhat challenging. This is due in part to the numerous confusing hybrids. Inthe past, some species and hybrids were lumped together, while other hybrids were treated as species, varieties and forms (Montgomery, 1981). This genus is now reasonably understood (there are still questions to be resolved) and the species that occur in Wisconsin will be addressed in this paper.
Taxon: Dryopteris fragrans (L.)
fragrant fern, fragrant wood fern
Description: Native, perennial fern that is listed as a “special concern” in Wisconsin because it is found in only 11 counties, primarily in the northern half of the state. The fronds are approximately 2” – 12” tapering from the middle to the base and tip, evergreen, pinnate-pinnatifid and the stipe is sparsely glandular with large, pale, reddish-brown scales at the base. There are usually 15-20 pairs of pinnae that form the body of the frond. A noteworthy characteristic is the persistence of the old fronds (brown) that are curled and hanging in masses below the plant. This fern sometimes hybridizes with D. marginalis to form D. xalgonquinensis. This hybrid is currently found in Michigan (Michigan Natural Features Inventory).
Habitat: Cliffs and prairies. More specifically, this species is found growing on rocks, talus slopes and in cliff crevices in shady locations.
Taxon: Dryopteris filix-mas (L.)
Description: Native, perennial fern 12”-48” long and 4”-12” wide. The blades are pinnate-pinnatifid to bi-pinnate and conspicuously narrowed at the base. The stipe is less than 1/4 the length of the frond, and bears 2 distinct types of scales, one broad and the other extremely narrow and hair-like.
Habitat: It grows in northern upland forests and it is identified as a "special concern" species in Wisconsin because it has only been documented in Ashland, Iron and Brown Counties. According to Gary Fewless, botany professor at UW-Green Bay, “The Brown County specimen is correctly identified, but the location is probably in error, perhaps due mixing of vouchers and subsequent mislabeling” .
Taxon: Dryopteris marginalis (L.)
marginal shield fern, marginal wood fern
Description: Native, perennial fern with fronds approximately 12”-40” long and 4”-10” wide. The blades are pinnate-pinnatifid to bi-pinnate and they are evergreen. It can be easily identified as D. marginalis by the sori which are located near the margin or edge of the pinnae.
Habitat: It is found mainly in the southwestern and northeastern counties, usually on rocks, or on steep slopes.
Taxon: Dryopteris goldiana (Hook.
ex Goldie) A.Gray
giant wood fern, Goldie's fern, Goldie's wood fern
Description: Native, perennial fern with fronds are pinnate-pinnatifid to bi-pinnate, 14”-48” long and 6” -16” wide and evergreen. The petiole is about 1/3 of the length of the frond and is conspicuously scaly, the broad scales dark colored with a lighter border. The lower pinnae are usually clearly narrowed at the base and the blade is not glandular.
Habitat: It is found in scattered locations throughout the state, and is generally uncommon. It is found in moist forests and on steep slopes, often near rocks but less commonly on them.
Taxon: Dryopteris clintoniana
Clinton's shield fern, Clinton's wood fern
Description: Native, perennial fern which has approximately 18”-40” long and 5”-8” wide, pinnate-pinnatifid and sterile fronds are evergreen (fertile fronds die in the winter). The basal pinnae are much smaller than those above and are elongate-triangular in shape.
Habitat: It is very rare and is known from only two locations in the southeastern portion of the state. Because of this, it has been identified as a "special concern" species. It is found in wet woods.
Taxon: Dryopteris cristata (L.)
crested shield fern, crested wood fern
Description: Native, perennial fern which has approximately 14”-28 long, 1/4 or less as wide as long and nearly uniform in width except where narrowed to the tip, pinnate-pinnatifid and sterile fronds are evergreen (fertile fronds die in the winter). Basal pinnae are broadly triangular.
Habitat: It is found throughout the state, where it occupies decidedly wet sites in both sunny and somewhat shaded habitats such as bogs, swamps, boreal forests, northern and southern lowland forests, sedge meadows and shrub carr.
Taxon: Dryopteris carthusiana
Common name - spinulose wood fern, toothed wood fern
Description: Native, perennial fern which has approximately 14" – 28”fronds. The blades are longer than wide, 2 pinnate-pinnatifid or further divided. Tan scales are conspicuous at least at the base of the stipe.
Dryopteris carthusiana and D. intermedia are similar in general appearance and both are common. For D. carthusiana the basioscopic pinnule is longer than the adjacent pinnules, and it is shorter than the adjacent pinnules in D. intermedia. Fronds of D. intermedia are evergreen and those of D. carthusiana are not, a character that is very helpful in winter and spring. Glands on the indusia and midribs of blade segments of D. intermedia are a good character, and although they can be difficult to see, they can be seen with a good hand lens or in the lab under the dissecting scope. D. carthusiana does not have glands.
D. expansa, although a rare species in Wisconsin, is similar to D. carthusiana. However, in its habitat there are as many as 200+ individual plants. It differs from D. carthusiana in that the basioscopic pinnules of D. expansa are very large relative to the upper acroscopic pinnules. Also, the fronds themselves are considerably larger (12” x 36”), and very triangular.
Habitat: Beech forests, bog, boreal forest, cliffs, northland lowland forests and southern upland forests. This fern is abundant in a variety of habitats.
Dryopteris intermedia (Muhl.
ex Willd.) A.Gray X D. marginalis (L.) A.Gray
Common name - glandular marginal wood fern
Description: Native, perennial fern which has approximately 14" – 28”fronds Fronds of Dryopteris intermedia range from 30-90 cm in length. The blades of D. intermedia are evergreen and those of D. carthusiana are not, a character that is very helpful in winter and spring. There are glands on the indusia and midribs of blade segments.
Habitat: Beech forests, bogs or swamps, boreal forest, northland lowland forests, southern upland forests. This fern is also abundant in a variety of habitats.
Dryopteris expansa (C.Presl)
Fraser-Jenk. & Jermy
Common name - northern wood fern, spreading wood fern
Description: Native, perennial fern that is rare which has approximately 12" – 36”fronds. The blade is large, tripinnate and very triangular with the lower (basioscopic) basal pinnule is much longer than the upper (acroscopic) basal pinnule. The fronds are reported in the literature to “die back slowly”. However, in Wisconsin, these fronds are the first to become senescent (process begins in July). It is listed as a "special concern" species in Wisconsin because it is restricted to the northern counties.
Cool moist woods and rocky slopes.
Britton, D.M. 1972. Spinulose wood-ferns, Dryopteris, in western North America. Can. Field. Nat. 96: 241-247.
Carlson, T.J. 1979. The Comparative ecology and frequencies of interspecific hybridization of Michigan woodferns. Mich. Bot. 18:47-56.
Montgomery, James D., and Edgar M. Paulton. 1982. Dryopteris in North America: Part II: The Hybrids. Fiddlehead Forum: Bulletin of The American Fern Society. Vol. 9, No. 4.
Montgomery, James D., and Edgar M. Paulton. 1981. Dryopteris in North America. Fiddlehead Forum: Bulletin of The American Fern Society. Vol. 8, No. 4.
Peck, James H., and W. Carl Taylor. 1980. Check List and Distriutions of Wisconsin Ferns and Fern Allies. Mich Bot. 19:251-268.
Wagner, W.H. Jr., and D.J. Hagenah. 1962. Dryopteris in the Huron Mountain Club area of Michigan. Brittonia 14: 90-100.
Wagner, W.H., Jr. 1971. Evolution of Dryopteris in relation to the Appalachians. Pp. 147-192 in P.C. Holt, The distributional history of the biota of the Southern Appalachians. Part II. Flora. Res. Monog. II, Virginia Polytechnic Inst., Blacksburg.
Ferns (Polypodiophyta), Glossary drawings, Page 1, 2, 3a, 3b, 4, 5, 6
Plants of Wisconsin
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