Onoclea sensibilis sensitive fern

A coarse, sturdy fern with broad, near triangular fronds, in habit of forming colonies. Pinnatifid in form, with winged rachis, and deeply lobed blades. Fiddleheads are a pale red, with a reddish cast to the margin of the blade as the fern uncurls. Sometimes confused with Woodwardia areolata with which it occasionally grows. Unlike W. areolata, sensitive fern has opposite lower pinnae on sterile fronds and pinnae margins are not toothed.

Habitat & Range

Grows in sandy, acidic/subacidic soils, open swamp, marshes, low woods, sun, or shade.

Range is New Foundland to Maine to the Gulf of Mexico, west to Mississippi, and to Kansas. Ascends to 3000 feet in VA.

Wetland codes

EMP:	FACW
NCNE:	FACW

Characteristics

Sterile fronds 8 to 40 in. long; do not overwinter.

Fertile fronds shorter than the sterile ones, erect, contracted, becoming blackish brown and firm in texture. Produced mid-summer to October and persisting for 2 to 3 years.

Sterile blade triangular, light grass green, scattered white hairs on undersurfaces. Cut into 12 or so nearly opposite pairs of pinnae.

Fertile blade numerous steeply ascending, very narrow pinnae. Sori in small, hard, beadlike divisions of fertile pinnae, at first green, dark brown when mature.

Sterile opposite. Lower pairs widely spaced and tapering to rachis, lowest or next to lowest pair the longest. Upper pinnae often connected by wings of leafy tissue to rachis; little or no tapering towards rachis. Margins wavy, not toothed. Larger plants sometimes with strong identations on pinnae margins. Veins depressed, prominent, and conspicuously netted.

Rachis smooth, winged, glistening; pale tan or yellowish.

Stipe longer than the blade, mahogany-colored, with a thick brown base and a few scales.

Rhizome stout, creeping, forking near the surface.

Sori completely enclosed by rolled edge of pinnae.