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

Ceratophyllum echinatum A. Gray
spring hornwort (spineless hornwort)
Ceratophyllaceae (Hornwort family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #11410)

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Distribution of Ceratophyllum echinatum
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Spineless hornwort is a perennial floating aquatic species endemic to North America where it is found primarily in the eastern part of the continent and then is disjunct in British Columbia, Washington and Oregon (USDA 2011). In British Columbia, it is found primarily in the southwestern part of the province, in lakes and sloughs in the lowland and montane zones. This species has coarse branching stems and usually no roots. Leaves are forked and arranged in whorls, and are sometimes toothed. Species in this genus are distinctively stiff to touch, and retain their shape when pulled from the water--aiding in identification of the genus.

In writing about the rare plants of the Fraser Valley, Lomer (2011) says: "An aquatic plant much like the common C. demersum, but more slender. It tends to grow in clearer, more acidic bog water than the latter species. [In the Fraser Valley], it has been found at Devil's Lake, west of Hope (Ceska 1978, unpublished), and I expect that further collecting will prove that this species is not rare in southwest BC, though there appear to be very few sites in the Fraser Valley."

A complete species description is given in Flora North America.

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, 2-4 times forked into linear or threadlike segments, these usually entire or sometimes finely 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, 5-7 mm long, ellipsoid, wing-margined with several lateral spines.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Lakes and sloughs in the lowland and montane zones; locally frequent on S Vancouver Island and the Gulf Islands, rare in the lower Fraser Valley and along the Alaska Highway; E to MI and ME and S to FL and MX.

Source: The Illustrated Flora of British Columbia

Additional Notes

This species is cold-water tolerant and is reported to overwinter under ice. It is often grown in aquatic gardens.


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 demersum var. echinatum (A. Gray) A. Gray
Ceratophyllum submersum var. echinatum (A. Gray) Wilmot-Dear

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References