[Ceratophyllum+Tricolpatae]
Ceratophyllales Link, Handbuch 2: 406. 4-11 Jul 1829 [‘Ceratophylleae’]; Ceratophyllanae Takht. ex Reveal et Doweld in Novon 9: 549. 30 Dec 1999; Ceratophyllidae Doweld, Tent. Syst. Plant. Vasc.: xxv. 23 Dec 2001
Genera/species 1/4–5?
Distribution Cosmopolitan except polar areas.
Fossils Fossil fruits, Donlesia dakotensis, from the latest Albian to the earliest Cenomanian (mid-Cretaceous) may be closely allied to Ceratophyllaceae, although it had basal placentation. Ceratostratiotes cretaceus, a fruit impression, was described from the Late Cretaceous of Israel, although its affinity to Ceratophyllaceae may be questioned. Ceratophyllum is frequent in layers from the Early to Late Cenozoic in the Northern Hemisphere. Fossil pollen grains are unknown.
Habit Monoecious, perennial herbs. Aquatic, with submersed stems and leaves, sometimes anchored in the sediment through rhizoid branches. Branches extra-axillary, alternating with leaves. Roots absent.
Vegetative anatomy Mycorrhiza absent. Phellogen absent. Aerenchyma schizogenous, as cylinder of air canals outside pericycle. Cambium and secondary lateral growth absent. Stem vascular tissue protostele (xylem with or without central air lacuna, with or without chloroplasts). Vessels absent. Imperforate tracheary xylem elements tracheids modified into unlignified elongate cells, starchy and tanniniferous. Wood rays absent. Axial parenchyma absent. Sieve tube plastids Ss type, with approx. ten starch grains. Nodes? Idioblasts absent. Crystals?
Trichomes Hairs usually absent (sometimes present, unicellular).
Leaves Usually verticillate (first leaves opposite), usually two to several times dichotomously divided with filiform lobes, with ? ptyxis. Stipules and leaf sheath absent. Petiole vascular bundle transection? Stomata absent. Cuticular waxes absent. Secretory glands abundant. Leaflet margins spinulose. Leaf tip with multicellular mucilaginous appendage.
Inflorescence Flowers extra-axillary, alternating with leaves, usually solitary (rarely several together). Floral prophylls (bracteoles) possibly absent.
Flowers Actinomorphic, small, sessile. Hypogyny? Tepals probably absent; replaced by whorl of six to 15 bracts (tepals?) connate at base and non-vascularized. Nectary absent. Disc absent.
Androecium Stamens three to 46, spiral. Filaments very short, flattened, free. Anthers basifixed, non-versatile, tetrasporangiate, extrorse-latrorse, longicidal (dehiscing by longitudinal slits) or irregularly dehiscent; connective flattened, thick, spur-like, prolonged, with spinulose-dentate edges. Tapetum secretory or amoeboid-periplasmodial, with uninucleate cells. Staminodia absent.
Pollen grains Microsporogenesis successive (in, e.g., Ceratophyllum demersum and C. submersum) or simultaneous (in, e.g., C. pentacanthum). Pollen grains inaperturate (to indistinctly monosulcate?), shed as monads, bicellular at dispersal. Exine highly reduced. Pollen grains with numerous starch grains. Pollen tube very long, spirally twisted, sometimes branched.
Gynoecium Pistil composed of usually a single carpel (rarely two free carpels, apocarpy); carpel ascidiate, postgenitally occluded by secretion, bilaterally symmetric. Closure by transverse slit occurring together with longitudinal slit. Ovary superior?, unilocular. Style short to relatively long, subulate, with stylar canal and usually entire (sometimes slightly bifid) apex. Stigma minute, as a pocket at orifice of stylar canal, without viscid secretions, Dry type. Pistillodium absent.
Ovules Placentation apical-ventral (or laminar-dorsal). Ovule one per ovary, almost orthotropous, pendulous, unitegmic, crassinucellar. Funicle without vascular strand. Integument four cell layers thick at base, two or three cell layers thick in middle, one cell layer thick at apex. Nucellar cap present. Hypostase tanniniferous. Megagametophyte monosporous, Polygonum type. Antipodal cells persistent. Endosperm development cellular. Endosperm haustorium chalazal (four large lower cells of endosperm haustorial). Embryogenesis asterad.
Fruit An achene, usually with warts, tubercles, spinules or wings, and with persistent style.
Seeds Aril absent. Seed coat thin and transparent, formed by outer epidermis of megasporangium. Testa absent or almost absent. Perisperm not developed. Endosperm thin, chalazal, mucilaginous, or absent. Suspensor absent. Embryo large, straight, with chlorophyll. Cotyledons two, thick, fleshy. Plumule large, green, consisting of eight to ten whorls of leaves, and a few lateral buds. Radicula minute, rudimentary and undifferentiated, ephemeral. Germination phanerocotylar.
Cytology n = 12, (19, 20, 24) 36 – Polyploidy occurring.
DNA
Phytochemistry Flavonols, flavone-O-glycosides, glycoflavones, anthocyanins, cyanidin, proanthocyanidins (prodelphinidins), and phenols present. Ellagic acids, alkaloids, and ethereal oils not found.
Use Aquarium plants, medicinal plants.
Systematics Ceratophyllum (4–5?; C. demersum, C. echinatum, C. muricatum, C. platyacanthum, C. submersum; nearly cosmopolitan).
Ceratophyllum has often been recovered as sister to either Tricolpatae or Liliidae (see, e.g. Barniske & al. 2012). Absence of ethereal oils may be a synapomorphy uniting Ceratophyllum with the tricolpates. However, in a four-gene study of mitochondrial DNA, Ceratophyllum was identified as sister to Chloranthaceae (Qiu & al. 2010). Likewise, Moore & al. (2011) found Ceratophyllum to be sister to Chloranthaceae based on an analysis of the plastid inverted repeat. The clade [Chloranthaceae+Ceratophyllum] was sister to the tricolpates. Barniske & al. (2012) recovered Ceratophyllum as sister to either Acorus (maximum parsimony strict consensus using substitutions and indels of all plastid genome regions) or all eudicots (maximum likelihood based on combined analyses of a number of intergenic spacers; then Acorus was sister to Chloranthus).
Species delimitations are notoriously problematical in Ceratophyllum.
Literature
Aboy HE. 1936. A study of the anatomy and morphology of Ceratophyllum demersum. – M.Sc. thesis, Cornell University, Ithaca, New York.
Avakov GS. 1962. A new fossil Ceratophyllum from the Oligocene deposits of the Zaysan basin. – Dokl. Akad. Nauk S.S.S.R. 145: 185-186. [In Russian]
Backman AL. 1943. Ceratophyllum submersum in Nordeuropa während der Postglazialzeit. – Acta Bot. Fenn. 31: 4-38.
Barniske A-M, Borsch T, Müller K, Krug M, Worberg A, Neinhuis C, Quandt D. 2012. Phylogenetics of early branching eudicots: comparing phylogenetic signal across plastid introns, spacers, and genes. – J. Syst. Evol. 50: 85-108.
Berger W. 1957. Eine neue fossile Wassernuß aus den untermiozänen Braunkohlenablagerungen von Langau bei Geras in Niederösterreich. – Phyton (Horn) 71: 152-158.
Buzek C. 1982. Ceratostratiotes Gregor, an extinct water plant of uncertain affinity from the European Miocene. – Vestn. Ustred. Ustavu Geol. 57: 285-298.
Dilcher DL. 1989. The occurrence of fruits with affinity to Ceratophyllaceae in Lower and mid-Cretaceous sediments. – Amer. J. Bot. 76: 162.
Dilcher DL, Wang H. 2009. An Early Cretaceous fruit with affinities to Ceratophyllaceae. – Amer. J. Bot. 96: 2256-2269.
Endress PK. 1994. Evolutionary aspects of the floral structure in Ceratophyllum. – Plant Syst. Evol. [Suppl.] 8: 175-183.
Engler A. 1891. Ceratophyllaceae. – In: Engler A, Prantl K (eds), Die natürlichen Pflanzenfamilien III(2), W. Engelmann, Leipzig, pp. 10-12.
Fassett NC. 1953. North American Ceratophyllum. – Comunic. Inst. Trop. Invest. Ci. El Salvador 2: 25-45.
Griffin K. 1980. A subfossil find of Ceratophyllum submersum in Norway. – Nytt Mag. Bot. 27: 207-217.
Herendeen PS, Les DH, Dilcher DL. 1990. Fossil Ceratophyllum (Ceratophyllaceae) from the Tertiary of North America. – Amer. J. Bot. 77: 7-16.
Hessland I. 1946. On the occurrence of subfossil Ceratophyllum submersum L. – Svensk Bot. Tidskr. 40: 235-256.
Iwamoto A, Shimizu A, Ohba H. 2003. Floral development and phyllotactic variation in Ceratophyllum demersum (Ceratophyllaceae). – Amer. J. Bot. 90: 1124-1130.
Iwamoto A, Izumidate R, Ronse De Craene LP. 2015. Floral anatomy and vegetative development in Ceratophyllum demersum: a morphological picture of an “unsolved” plant. – Amer. J. Bot. 102: 1578-1589.
Jedrychowska A, Sroczynska A. 1934. On the cytology and embryology of Ceratophyllum submersum. – Acta Soc. Bot. Poloniae 11: 423-441.
Jones EN. 1931. The morphology and biology of Ceratophyllum demersum. – Stud. Nat. Hist. Iowa Univ. 13: 11-15.
Klercker JEF de. 1885. Sur l’anatomie et de développement de Ceratophyllum. – Bih. Kungl. Sv. Vetensk.-Akad. Handl. 9: 1-22.
Krassilov VA, Lewy Z, Nevo E, Silantieva N. 2005. Late Cretaceous (Turonian) flora of southern Negev, Israel. – Pensoft, Sofia-Moscow.
Les DH. 1980. Contributions to the biology and taxonomy of Ceratophyllum in the eastern United States. – M.Sc. thesis, Eastern Michigan University, Ypsilanti, Michigan.
Les DH. 1985a. The taxonomic significance of plumule morphology in Ceratophyllum (Ceratophyllaceae). – Syst. Bot. 10: 338-346.
Les DH. 1985b. Ceratophyllaceae. – In: Leach GJ, Osborn PL (eds), Freshwater plants of Papua New Guinea, University Press, Papua New Guinea.
Les DH. 1986a. The systematics and evolution of Ceratophyllum L. (Ceratophyllaceae): a monograph. – Ph.D. diss., Ohio State University, Columbus, Ohio.
Les DH. 1986b. The phytogeography of Ceratophyllum demersum and C. echinatum (Ceratophyllaceae) in glaciated North America. – Can. J. Bot. 64: 498-509.
Les DH. 1986c. The evolution of achene morphology in Ceratophyllum (Ceratophyllaceae) I. Fruit-spine variation and relationships of C. demersum, C. submersum, and C. apiculatum. – Syst. Bot. 11: 549-558.
Les DH. 1988a. The evolution of achene morphology in Ceratophyllum (Ceratophyllaceae) II. Fruit variation and systematics of the ‘spiny-margined’ group. – Syst. Bot. 13: 73-86.
Les DH. 1988b. The evolution of achene morphology in Ceratophyllum (Ceratophyllaceae) III. Relationships of the ‘facially-spined’ group. – Syst. Bot. 13: 509-518.
Les DH. 1988c. The origin and affinities of the Ceratophyllaceae. – Taxon 37: 326-345.
Les DH. 1989. The evolution of achene morphology in Ceratophyllum (Ceratophyllaceae) IV. Summary of proposed relationships and evolutionary trends. – Syst. Bot. 14: 254-262.
Les DH. 1993. Ceratophyllaceae. – In: Kubitzki K, Rohwer JG, Bittrich V (eds), The families and genera of vascular plants II. Flowering plants. Dicotyledons. Magnoliid, hamamelid and caryophyllid families, Springer, Berlin, Heidelberg, New York, pp. 246-250.
Lowden RM. 1978. Studies on the submerged genus Ceratophyllum L. in the Neotropics. – Aquatic Bot. 4: 127-142.
Mai DH. 1985. Entwicklung der Wasser- und Sumpfpflanzen-Gesellschaften Europas von der Kreide bis ins Quartär. – Flora 176: 449-511.
Mouraviev I. 1945. Recherches sur la microspore du genre Ceratophyllum. – Bull. Mens. Soc. Linn. Lyon 14: 73-82.
Mouraviev I. 1952. Sur les membranes externs de l’épiderme du genre Ceratophyllum L. La cuticule. – Bull. Mens. Soc. Linn. Lyon 14: 73-82.
Muenscher WC. 1940. Fruits and seedlings of Ceratophyllum. – Amer. J. Bot. 27: 231-233.
Oganezova EP, Nalbandyan RM. 1976. Purification and properties of plastocyanin and ferredoxin from Ceratophyllum demersum L. – Biokhimiya (Moscow) 41: 794-800. [In Russian]
Qiu Y-L, Li L, Wang B, Xue J-Y, Hendry TA, Li R-Q, Brown JW. 2010. Angiosperm phylogeny inferred from sequences of four mitochondrial genes. – J. Syst. Evol. 48: 391-425.
Rutishauser R, Sattler R. 1987. Complementary and heuristic value of contrasting models in structural botany II. Case study on leaf whorls: Equisetum and Ceratophyllum. – Bot. Jahrb. Syst. 109: 227-256.
Samylina VA. 1976. The Cretaceous flora of Omsukchan (Magadan District). – Nauka, Leningrad.
Sastri RLN. 1955. Embryology of Ceratophyllum demersum L. – Proc. Indian Sci. Cong. 3: 226.
Schneider El, Carlquist S. 1996. Conductive tissue of Ceratophyllum demersum L. – Sida 178: 437-443.
Schröter C. 1917. 42. Familie. Ceratophyllaceae. – In: Kirchner O von, Loew E, Schröter C (eds), Lebens-geschichte der Blütenpflanzen Mitteleuropas, Eugen Ulmer, Stuttgart, pp. 51-73.
Sehgal A, Mohan Ram HY. 1981. Comparative developmental morphology of two populations of Ceratophyllum L. (Ceratophyllaceae) and their taxonomy. – Bot. J. Linn. Soc. 82: 343-356.
Shamrov II. 1981. Some peculiar features of the development of the anther in Ceratophyllum demersum and C. pentacanthum (Ceratophyllaceae). – Bot. Žurn. 66: 1464-1473. [In Russian with English summary]
Shamrov II. 1983. Anthecological investigation of three species of the genus Ceratophyllum (Ceratophyllaceae). – Bot. Žurn. 68: 1357-1366. [In Russian with English summary]
Shamrov II. 1997. Ovule and seed development in Ceratophyllum demersum (Ceratophyllaceae). – Bot. Žurn. 82: 1-13. [In Russian with English summary]
Shamrov II. 2009. The morphological nature of gynoecium and fruit in Ceratophyllum (Ceratophyllaceae). – Bot. Žurn. 94: 938-961. [In Russian]
Ståhl B. 2003. 55B. Ceratophyllaceae. – In: Harling G, Andersson L (eds), Flora of Ecuador 70, Botanical Institute, Göteborg University, pp. 25-28.
Strasburger E. 1902. Ein Beitrag zur Kenntniss von Ceratophyllum submersum und phylogenetische Erörterungen. – Jahrb. Wiss. Bot. 34: 477-524.
Sundari KT, Radharkri M, Narayana LL. 1982. Chemotaxonomy of Ceratophyllum. – Acta Bot. Indica 10: 304.
Terasmae J, Craig BG. 1958. Discovery of fossil Ceratophyllum demersum L. in Northwest Territories, Canada. – Can. J. Bot. 36: 567-569.
Wang Y-F, Ferguson DK, Li C-S. 2005. Ceratophyllum (Ceratophyllaceae) from the Miocene of eastern China and its Paleoecological significance. – Syst. Bot. 30: 705-711.
Wilmot-Dear CM. 1985a. Ceratophyllum revised: a study in fruit and leaf variation. – Kew Bull. 40: 243-271.
Wilmot-Dear CM. 1985b. Ceratophyllaceae. – In: Polhill RM (ed), Flora of tropical East Africa, A. A. Balkema, Rotterdam, pp. 1-5.