USGS - science for a changing world

Northern Prairie Wildlife Research Center

  Home About NPWRC Our Science Staff Employment Contacts Common Questions About the Site

Aquatic and Wetland Vascular Plants of the Northern Great Plains

4. Polypodiaceae, the Polypody Family

5. Onoclea L. -- Sensitive fern

1. Onoclea sensibilis L.


Rhizomes spreading and branching, 4-7 mm thick, the scales caducous. Fronds annual, erect, dimorphic, the fertile fronds brown, structurally unlike the green sterile fronds. Sterile fronds pinnate at the base, pinnatifid upward, the rachis broader-winged toward the tip; blades mostly 10-30 cm long, 10-35 cm wide, with 8-12 pairs of opposite pinnae, these sinuate to pinnatifid, 1-3 cm wide, sparsely white-hairy on the veins beneath, the veins anastomosing; petioles shorter to about as long as the blade. Fertile frond surpassed by the sterile ones; blade pinnate-pinnatifid, mostly 5-15 cm long; pinnae strongly ascending, 2-5 cm long, divided into bead-like pinnules with inrolled margins enclosing the sori, the pinnules 3-4 mm wide, becoming dry, hard, eventually separating to release the spores; sori globose, covered by a delicate, hoodlike indusium. Fertile fronds produced Aug--Sep, often persistent into the following year. Swampy woods, wet meadows and marshes, where water is fresh; scattered from e ND to NE, especially common in the Sand Hills; (Newf. to Man., s to FL and TX).
GIF-Onoclea sensibilis GIF- Distribution Map

Map key

Onoclea sensibilis, a vegetative frond with pinnatifid divisions and an associated dark brown fertile frond, both arising from a rhizome.  

Previous Species -- Matteuccia struthiopteris (L.) Todaro
Return to Family -- Polypodiaceae - The Polypody Family
Next Species -- Thelypteris palustris Schott -- Marsh fern

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/plants/vascplnt/species/onocsens.htm
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:45:00 EST
Sioux Falls, SD [sdww54]