Photo © Robert Moseley CLICK PHOTO FOR A LARGER IMAGE

Dryopteris cristata (L.) Gray

Crested Shield-fern

Dryopteridaceae (Wood fern family)

Synonym: Polypodium cristatum L.

General Description: A pale green fern with dimorphic leaves, 35-70 by 8-12 cm, clustered on a short rhizome. The fertile leaves are deciduous, larger, and tend to be erect, compared to the smaller, more spreading, evergreen sterile leaves. Petioles are 1/4 to 1/3 the length of the leaf, with scattered tan scales. The blade is green, more or less lance-shaped, pinnate-pinnatifid, and not glandular. Pinnae of fertile leaves are twisted out of plane of the blade and perpendicular to it, with margins distantly serrate with spiny teeth. Sori are located midway between the midvein and the segment margin.

Illustration.

Field Identification Tips: Sterile leaves are evergreen, smaller, and more spreading compared to the fertile leaves. Identification can be complicated by the presence of hybrids in the field.

Phenology: Spores released June through September.

Similar Species: Dryopteris cristata differs from other members of the genus in Idaho by having less dissected leaves. It can occur with Athyrium filix-femina (lady-fern) but can be differentiated by its narrower, dimorphic leaf blades that are less dissected.

Photo © Robert Moseley CLICK PHOTO FOR A LARGER IMAGE

Habitat: Wet meadows, forested wetlands, and open shrubby wetlands. In Idaho, often found on hummocks, downed woody debris, or at the base of deciduous shrubs in wetlands where soils are high in organic matter.

Global Distribution: Across southern Canada from British Columbia to Newfoundland, southward to North Carolina, through the Ohio Valley and Great Lake states, and in Washington, northern Idaho, and northwestern Montana.

Idaho Distribution: Boundary and Bonner counties in the Panhandle region.

References:

Bursik, R. J. 1992. Field investigations of sensitive plant taxa occurring on the Priest Lake Ranger District, Kanisku National Forest, Idaho Panhandle National Forests. Unpublished report prepared for the Panhandle National Forests by the Idaho Department of Fish and Game, Conservation Data Center, Boise. 141 pp. plus appendices.

Caicco, S. L. 1987. Field investigations of selected sensitive plant species on the Idaho Panhandle National Forest. Unpublished report prepared for the Panhandle National Forests by the Idaho Department of Fish and Game, Conservation Data Center, Boise. 44 pp. plus appendices.

Flora North America Editorial Committee. 1993. Flora of North America, Vol. 2. Pteridophytes and Gymnosperms. Oxford University Press, Inc., New York. 475 pp.

Montana Natural Heritage Program. Montana rare plant field guide. Available at: http://nhp.nris.state.mt.us.

Moseley, R. K. 1989. Field investigations of 16 rare plant taxa occurring in wetlands on the Bonners Ferry Ranger District, Idaho Panhandle National Forest. Unpublished report prepared for the Panhandle National Forests by the Idaho Department of Fish and Game, Conservation Data Center, Boise. 75 pp. plus appendices.

Moseley, R. K. 1990. Field investigations of eight rare plant taxa occurring in wetlands on the Sandpoint Ranger District, Idaho Panhandle National Forests. Unpublished report prepared for the Panhandle National Forests by the Idaho Department of Fish and Game, Conservation Data Center, Boise. 42 pp. plus appendices.