Compilation
Ceratophyllum submersum

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Name

Identification
Isotype of Ceratophyllum muricatum Cham. [family CERATOPHYLLACEAE ] Verified by Les, D.H., Ceratophyllum submersum L. [family CERATOPHYLLACEAE ] (stored under name); Verified by Not on sheet.,
Related name
  • Ceratophyllum cristatum
  • Ceratophyllum demersum
  • Ceratophyllum muricatum
  • Ceratophyllum submersum
Common name
  • cornifle échinée, Flora of North America Vol. 3
  • Hornwort, Flora of North America Vol. 3

Flora

Entry for Ceratophyllum echinatum A. Gray [family CERATOPHYLLACEAE]
Herbarium
Flora of North America (FNA)
Collection
Flora of North America
Resource Type
Reference Sources
Entry From
Flora of North America, Vol 3,
Names
Ceratophyllum echinatum A. Gray [family CERATOPHYLLACEAE], Ann. Lyceum Nat. Hist. New York, 4: 49. 1837
Ceratophyllum demersum Linnaeus var. echinatum (A. Gray) A. Gray [family CERATOPHYLLACEAE]
Ceratophyllum submersum Linnaeus var. echinatum (A. Gray) Wilmot-Dear [family CERATOPHYLLACEAE]
Information
Stems to 1 m; apical leaf whorls not densely crowded. Leaves dark green or olive-green, fine-textured. Leaf blade simple or forked into 2-10 ultimate segments (forking of largest leaves 3d or 4th order), proximal segments often conspicuously inflated, mature leaf whorls 25-55 mm diam., marginal denticles weak and inconspicuous, weakly exserted, not raised on broad base of green tissue; 1st leaves of plumule forked. Achene dark green or brown, body (excluding spines) 4.5-6 × 2.5-4.5 × 1.5-3 mm, basal spines 2 (rarely absent), straight or curved, 1-5 mm, marginal spines 2-13, 0.5-6.5 mm, terminal spine straight, 1.5-7.5 mm, margins winged. 2n = 24.
Phenology
Flowering spring-summer
Altitude range
0-500 m
Distribution
USA Ala.USA Ark.USA Conn.USA Del.USA D.C.USA Fla.USA Ga.USA Ill.USA Ind.USA IowaUSA Kans.USA Ky.USA La.USA MaineUSA Md.USA MassUSA Mich.USA Minn.USA Miss.USA Mo.USA N.H.USA N.J.USA N.Y.USA N.C.USA OhioUSA Okla.USA Oreg.USA Pa.USA R.I.USA S.C.USA Tenn.USA Tex.USA Vt.USA Va.USA Wash.USA W.Va.USA Wis.Canada B.C.Canada Man.Canada N.B.Canada N.S.Canada Ont.Canada Que.
Discussion
Principally an eastern North American species--and the only species of its genus endemic to North America--Ceratophyllum echinatum is disjunct in the Pacific Northwest as a result of repeated Pleistocene glaciation. The habitats of C. echinatum are typically more acidic (avg. pH 6.6) than those of C. demersum (avg. pH 7.4). The two species only rarely coexist. Ceratophyllum echinatum also thrives in cooler, clearer, and more oligotrophic water than C. demersum and often is found in more ephemeral sites, such as shrub swamps (e.g., with Cephalanthus occidentalis) and beaver ponds.
This species, relatively uncommon, is fast disappearing from much of its range because of habitat alteration or destruction and the introduction of nonindigenous species; steps should be taken to secure its conservation. Unlike Ceratophyllum demersum, C. echinatum does not attain status as a serious weed.

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