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Common name: Hornwort Family.
Number of genera 1. Number of species 2 (Ceratophyllum demersum L., C. submersum L.).
Angiosperm. Magnoliopsida.
Disseminule an intact or entire fruit.
Fruits
Pistil(s) simple; 1; 1-pistillate. Fruit pericarpium; simple; achene (Spjut Fig. 3D-E); without persistent central column; with styles(s) (often spiny); at apex; not within accessory organ(s); 1-seeded; 1-seeded; 1-carpellate; in transection terete (ovoid or ellipsoid); apex not beaked; wall hard; indehiscent. Epicarp durable; crustaceous, or leathery; glabrous (without hairs); with armature, or without armature; with spines; without armature glochidiate; smooth, or not smooth; warted; without wing(s); without apical respiratory hole. Endocarp present; not separating from exocarp; thin; not splitting into 1-seeded pyrenes; smooth; without wing; without operculum; without secretory cavities; without mechanism for seedling escape; without grooves; without longitudinal ridges. Funiculus short; short without seed bearing hooks (retinacula); not persisting in fruit after seed shed.
Seeds
Aril absent. Seed minute; in transection sub terete; not bowl shaped; not nutlike; without winglike beak; without caudate appendage(s); at maturity without food reserves, or with food reserves; with endosperm; without canavanine. Sarcotesta absent. Testa present; without fleshy or leathery layer over hard layer; surface smooth, or unsmooth; surface with depressed features; surface grooved (caused by embryo); without crease or line separating cotyledons from hypocotyl-radicle; without notch along margin where cotyledons from hypocotyl-radicle tip approach each other; without glands; without bristles; glabrous; without wings; without collar; without operculum; colored; monochrome; thin, or membranous; not becoming mucilaginous when wetted. Hilum punctate. Endosperm development cellular.
Embryo differentiated from food reserve; well developed; 1 per seed; completely filling testa (no food reserve); at one end of seed not extending into a depression or cup; straight; parallel to seed length; without coleorhiza; without simmondsin; without stomata; green; with 2 or more cotyledons. Cotyledons 2; with apices entire; with margins separate; basally entire; equal in size; not punctate dotted. Hypocotyl-radicle vestigial; not thickened. Plumule well developed; composed of several seed-leaves; straight; terminal between 2 cotyledons.
Distribution
Cosmopolitan (except for colder parts of Northern Hemisphere). New World, Old World. North America, Middle America, South America, Europe, Africa, Asia Major, Asia Minor, southeastern Asia, Australia, Oceania.
Weed information
1 or more USA state noxious weeds.
USA states and territories with listed noxious weeds: Puerto Rico (PR).
USA state and territory noxious weeds: -- Ceratophyllum demersum L.: USA state noxious weed: PRª. -- Ceratophyllum spp.: USA state noxious weed: PRª. -- Symbols: ªaquatic weed; ●terrestrial weed; °weed in seed. -- Last updated September 2008.
Listed seeds
ISTA listed seeds.
ISTA listed seeds: -- Ceratophyllum demersum L.w -- Symbols: aagricultural and vegetable seeds (Table 2A Part 1); ttree and shrub species (Table 2A Part 2); fflower, spice, herb, and medicinal seeds (Table 2A Part 3); wweed seeds. -- Last updated September 2008.
Accepted genera
Ceratophyllum L.
References specific to this family
Cronquist page 114. Wilmot-Dear, M. 1985. Ceratophyllum revised: A study in fruit and leaf variation. Kew Bull. 40:243–271; Muenscher, W.C. 1940. Fruits and seedlings of Ceratophyllum. Amer. J. Bot. 27:231–233.
General references
Baillon, H.E. 1866–95. Histoire des plantes, 13 vols. Hachette and Co., Paris, Corner, E.J.H. 1976. The seeds of Dicots, esp. vol. 2. Cambridge University Press, New York, Cronquist, A. 1981. An integrated system of classification of flowering plants, 1,262 p. Columbia University Press, New York, Gaertner, J. 1788–1805. De fructibus et seminibus plantarum. The Author, Stuttgart, Goldberg, A. 1986 (dicots) and 1989 (monocots). Classification, evolution, and phylogeny of the familes of Dicotyledons. Smithsonian Contr. Bot. 58 for dicots (314 pp.) and 71 for monocots (74 pp.). [Goldberg's illustrations are reproduced from older publications and these should be consulted], Gunn, C.R., J.H. Wiersema, C.A. Ritchie, and J.H. Kirkbride, Jr. 1992 and amendments. Families and genera of Spermatophytes recognized by the Agricultural Research Service. Techn. Bull. U.S.D.A. 1796:1–500, LeMaout, E. and J. Decaisne. 1876. A general system of botany, 1,065 p. Longmans, Green, and Co., London, Mabberley, D.J. 1987. The plant-book, 706 p. Cambridge University Press, Cambridge, Spjut, R.W. 1994. A systematic treatment of fruit types. Mem. New York Bot. Gard. 70:1–182.
Illustrations
Acceptable fruit and seed illustration. Cronquist has no illustration. Disseminule illustration(s): fruit, or seed, or embryo. Fruit illustration(s): Wilmot-Dear, Muenscher (1940). Seed illustration(s): LeMaout & Decaisne, Karen. Embryo illustration(s): LeMaout & Descaisne, Baillon, Karen. Karen's plate number and taxon (taxa): 029: Ceratophyllum demersum L. (A-B).
• Fruit. 1 of 4. Ceratophyllum demersum L.: fruit. • Seed. 2 of 4. Ceratophyllum demersum L.: seeds. • Fruit. 3 of 4. Ceratophyllum submersum L.: fruit. • Embryo. 4 of 4. Ceratophyllum demersum L.: embryo.
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘J.H. Kirkbride, Jr., C.R. Gunn, and M.J. Dallwitz. 2000 onwards. Family guide for fruits and seeds: descriptions, illustrations, identification, and information retrieval. Version: 12th April 2021. delta-intkey.com’.
