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Northern Prairie Wildlife Research Center

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Wetland Plants and Plant Communities of Minnesota and Wisconsin


(Silphium terebinthinaceum Jacq.)

Prairie dock

ASTER FAMILY (Compositae or Asteraceae)


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).

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