USGS - science for a changing world

Northern Prairie Wildlife Research Center

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

Wetland Plants and Plant Communities of Minnesota and Wisconsin

PRAIRIE DOCK

(Silphium terebinthinaceum Jacq.)


Prairie dock

ASTER FAMILY (Compositae or Asteraceae)

IND. STATUS: [FAC-]

FIELD CHARACTERISTICS: A coarse, perennial herb 0.5-3 m. high. The essentially hairless stems support reduced stem leaves. The huge (to 4 dm. wide) principal leaves are essentially basal, rough, sharply toothed, heart-shaped to oblong, and supported by long leaf stems. Leaves are often oriented edgewise to the south or southwest. The inflorescence is open and resembles a corymb with both ray and disc flowers present. The conspicuous, yellow ray flowers have pistils and are fertile, while the disc flowers are sterile. The ray flower nutlets are flattened and winged along their margins. In flower from the end of June through September.

ECOLOGICAL NOTES: Prairie dock is common in wet-mesic to dry-mesic prairies. It also occurs infrequently in dry prairies and oak openings.

SOURCE: Gleason and Cronquist (1991); and Swink and Wilhelm (1994).


Previous Section -- Sawtooth Sunflower (Helianthus grosseserratus Martens)
Return to Contents
Next Section -- Western Prairie Fringed Orchid (Platanthera praeclara Shev. & Bowls.)

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/mnplant/site.htm
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:33:02 EST
Menlo Park, CA [caww55]