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

8. Ceratophyllaceae, the Hornwort Family

1. Ceratophyllum L. -- Hornwort, coontail

1. Ceratophyllum demersum L.


Rootless perennial aquatic, entirely submersed, free-floating or more often anchored by the older decaying portion of the stem. Stems delicate, freely branching, the living portion usually no more than a few dm long, often fragmenting as water warms during summer. Leaves sessile, whorled, 5-12 at each node, once or twice dichotomously branched into filiform segments, 5-30 mm long, sparsely to conspicuously spinulose, spreading to curving upward, more crowded toward the branch tips to give the coontail appearance. Flowers minute, imperfect, solitary and sessile in the leaf axils, both male and female flowers subtended by an involucre or perianth of 8-15 greenish segments; male flowers containing 10-16 stamens; female flowers each consisting of a single unicarpellary pistil. Fruit a dark olive, ellipsoid achene, usually with 1 terminal and 2 basal spinelike projections, the achene body 4-5 mm long. Jun--Sep. Quiet water of lakes, ponds, marshes and streams; common, often abundant; (Cosmopolitan).
GIF-Ceratophyllum demersum GIF- Distribution Map
Ceratophyllum demersum.
Map key

Return to Family -- Ceratophyllaceae - The Hornwort Family

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/cerademe.htm
Page Contact Information: Webmaster
Page Last Modified: Saturday, 02-Feb-2013 06:41:07 EST
Sioux Falls, SD [sdww54]