E-Flora BC: Electronic Atlas of the Flora of British Columbia

Ceratophyllum demersum L.
common hornwort (coon's tail; coontail)
Ceratophyllaceae (Hornwort family)

Introduction to Vascular Plants

© Royal BC Museum (Tom Armstrong)  Email the photographer   (Photo ID #2217)

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Distribution of Ceratophyllum demersum
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Species Information

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Aquatic herb, usually without roots; stems freely branching, 0.3-4.0 m long.
Stem leaves submerged, in whorls of 5-12, 2-3 times forked into linear or threadlike segments, these often stout, stiff and spiny-toothed.
Inflorescence of solitary, minute, axillary flowers; petals lacking; sepals 3-15, sometimes petal-like; stamens 12-16.
Achenes usually lacking, if present then much flattened, 4-6 mm long, ellipsoid, wingless with a persistent style and 2 basal spines.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: White
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Ponds, lakes and slow-moving streams in the lowland, steppe and montane zones; common in S BC, less frequent northwards; N to AK, YT and NT, E to PQ, NS and NB and S to FL, TX, CA and MX.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Ceratophyllum demersum

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 840 1067 1118
Slope Gradient (%) 0 0 1
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
301 300 301
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
7 7 8
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: CDF(3), CWH(2), ICH(1), IDF(1), SBPS(7)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Ceratophyllum apiculatum Cham.
Ceratophyllum demersum var. apiculatum (Cham.) Asch.
Ceratophyllum demersum var. apiculatum (Cham.) Garcke

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References