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Gymnocarpium dryopteris

Oak Fern

At a Glance: Delicate, deciduous fronds. Usually solitary, but often forms a mat of herbaceous cover in forests.

Height: To 16 inches (40 cm).
Growth Form: Fern.
Stems: Stalks are thin, dark, and wiry.
Leaves: Fronds with up to 20 pairs of leaflets, the ultimate segments round-toothed; shape: twice- to thrice-pinnately compound, broadly triangular, with the two lateral pinnae shorter than the central one and the lowest pinnae noticeably asymmetrical; size: to 40 cm (16 in) tall; color: dark green.
Flowers: None; produces spores in small, circular, sori arranged in two rows on lower leaflets; indusia lacking.
Flowering Period: none.


Photo © Starflower Foundation

Sun/Shade Tolerance	Hydrology	Elevation Range
full sun > 80% mostly sunny 60%-80% partial sun and shade 40%- 60% mostly shady 60%-80% full shade > 80%	wet moist dry Wetland Indicator Status:	Mostly found at mid-elevations. low elevation mid elevation sub-alpine high elevation

Soil Preferences
(data not available)

Habitat Preferences
Aquatic and Wetland: Ponds or lakes Shallow pools Sloughs Swales or wet ditches Seasonally inundated areas Marshes or swamps Aquatic bed wetlands Emergent wetlands Scrub-shrub wetlands Forested wetlands Bogs, fens Seeps, springs Shorelines and Riparian: Lake shores Bog margins Streams or rivers Stream or river banks Riparian corridors River bars Floodplains Bottomlands Alluvial areas	Saltwater Areas: In or near saltwater Mud flats Tidal areas Estuaries Saltmarshes Brackish water Seashores Coastal dunes or beaches Rocky or Gravelly Areas: Coastal bluffs Cliffs Rocky slopes Outcrops Crevices Glacial outwash Gullies Slide areas Sub-alpine and Alpine: Heaths Snow beds Tundra Avalanche tracks	Forests and Thickets: Forests and woods Open forests Coniferous forests Old growth forests Deciduous forests Mixed forests Nurse logs Forest edges, openings, or clearings Thickets Meadows and Fields: Pastures or fields Meadows or grassy areas Mossy areas Disturbed Areas: Roadsides Trailsides Logged sites Burned areas Disturbed sites

Wildlife Value
Berries Seeds Nectar for hummingbirds Nectar for butterflies Host for insect larvae Thickets and shelter Thorny or protective cover	Mammals: Forms dense herbaceous stands useful as a cover for forest wildlife.

Ethnobotanical Uses and Other Facts

Landscape Uses: This species can form an almost continuous carpet over the forest floor on some sites. It is a very attractive fern, and it forms a beautiful, luxuriant forest understory. Small pieces dug in the wild can be easily established in shady garden spots.
Name Info: Gymnocarpium means naked fruit because these plants have no indusia. The name oak fern appears to have resulted from a translation of the species name: Dryopteris is Greek for oak (drys) fern (pteris). This fern does not grow near or on oaks, but oak fern is a former name for Polypodium vulgare, from that species habit of growing on oak branches.

Suggested References

Cooke, S.S. A Field Guide to the Common Wetland Plants of Western Washington and Northwetern Oregon. Seattle Audubon Society and Washington Native Plant Society. Page 375.
Hitchcock, C.L., A. Cronquist. 1973. Vascular Plants of the Pacific Northwest. University of Washington Press. Page 51.
Kruckeberg, A.R. 1996. 2nd ed. Gardening with Native Plants of the Pacific Northwest. University of Washington Press. Page 136.
Pojar, J., A. Mackinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing. Page 423.

The landscaping and restoration information provided on this page is taken from Starflower Foundation Image Herbarium. All photographs © Starflower Foundation unless otherwise noted.