1. Ceratophyllaceae Gray

    1. This family is accepted.

[FWTA]

Ceratophyllaceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Habit
Aquatic submerged herbs with leafy floating branches
Leaves
Leaves verticillate, variously divided with thread-like or linear segments
Flowers
Flowers monoecious, solitary in the whorls, the males and females at separate nodes, sessile Male flowers: stamens 10–22, crowded on a flat torus; anthers almost sessile, erect, linear-oblong, 2-celled, cells parallel, opening lengthwise; connective produced beyond the cells, thick and often coloured Female flowers: staminodes 0; ovary sessile, ovoid, 1-celled; style continuous with the ovary
Calyx
Calyx thinly herbaceous, many-parted into narrow subvalvate segments often dentate or lacerate at the apex
Male
Male flowers: stamens 10–22, crowded on a flat torus; anthers almost sessile, erect, linear-oblong, 2-celled, cells parallel, opening lengthwise; connective produced beyond the cells, thick and often coloured
Female
Female flowers: staminodes 0; ovary sessile, ovoid, 1-celled; style continuous with the ovary
Gynoecium
Ovule 1, pendulous
Fruits
Fruit a nut, ovoid or ellipsoid
Seeds
Seed pendulous; endosperm 0; embryo straight; cotyledons oblong, equal; radicle very short, the plumule already well developed and showing several leaves in the seed
[FTEA]

Ceratophyllaceae, C.M. Wilmot-Dear. Flora of Tropical East Africa. 1985

Habit
Aquatic herbs, monoecious, perennating by buds, usually free-floating
Leaves
Leaves in whorls of (6–)8–11, filiform, dichotomously branched, often with few–many spine-tipped teeth on margins especially of distal segments; terminal segments truncate, 2-spined and with a central reddish terete soon deciduous projection ± 0.2 mm. long
Flowers
Flowers axillary, 1-several per node, ? and ? at different nodes Female flowers sessile or shortly pedicellate, without staminodes; ovary solitary, superior, sessile, tapering into long style; ovule 1, pendulous Male flowers subsessile, with numerous stamens in several whorls on domed torus around pistillode; filaments very short or absent; anthers oblong, extrorse; thecae 2, parallel, dehiscing longitudinally; connective produced apically into 2 spines and a central projection as in perianth-lobes, often with 1–3 spines on margins; immature anthers much flattened, resembling perianth-lobes, later swollen, oblong, reddish projection detaching, tissues becoming gas-filled and bearing detached anther to water-surface where it becomes horizontal, dehisces and sheds pollen on to plants below
Perianth
Perianth of 6–13 strap-shaped or obovate lobes united at base and some united in pairs to over half their length, often with a single hyaline spine on each margin, truncate with 2 spines and a central projection as in leaves
Male
Male flowers subsessile, with numerous stamens in several whorls on domed torus around pistillode; filaments very short or absent; anthers oblong, extrorse; thecae 2, parallel, dehiscing longitudinally; connective produced apically into 2 spines and a central projection as in perianth-lobes, often with 1–3 spines on margins; immature anthers much flattened, resembling perianth-lobes, later swollen, oblong, reddish projection detaching, tissues becoming gas-filled and bearing detached anther to water-surface where it becomes horizontal, dehisces and sheds pollen on to plants below
Female
Female flowers sessile or shortly pedicellate, without staminodes; ovary solitary, superior, sessile, tapering into long style; ovule 1, pendulous
Fruits
Fruit a hard nut, ovoid or ellipsoid, slightly laterally flattened, wingless and rimless, or more markedly flattened and then often with marginal longitudinal ‘rim’ or entire to dentate or spinulose wing; style ± persistent and spinose; base often with a pair of prominent spines; rest of surface often gland-dotted, spiny or warty; embryo straight; endosperm absent
Distribution
A worldwide family of one genus only
[FZ]

Ceratophyllaceae, C. M. Wilmot-Dear. Flora Zambesiaca 9:6. 1991

Habit
Submerged aquatic, branching, usually rootless herbs, perennating by buds, monoecious
Leaves
Leaves in whorls, filiform, once or more dichotomously branched, margins ± spinose-dentate; apical segments truncate, 2-spined at the apex with a reddish glandular projection between the spines (basal segments sometimes parasitised, becoming swollen and sac-like)
Flowers
Flowers axillary, 1-several per node, male and female flowers at different nodes, ± sessile; perianth lobes 6–13, united at the base, strap-shaped or obovate, margin often with a single lateral hyaline spine or ± lacerate, apex as for leaf apex Female flowers sessile or shortly pedicellate; staminodes absent; ovary superior, sessile, ovoid, tapering into a long style; ovule 1, pendulous Male flowers subsessile; stamens up to c. 30 in several whorls on a domed torus around the pistillode; filaments short or absent; anthers oblong, extrorse, 2-locular, dehiscing longitudinally, connective produced apically into 2 spines and a central projection as in perianth lobes, immature anthers resembling perianth lobes, margins 1–3 spined; mature anthers detach and float to the water-surface where they dehisce and shed pollen on to plants below
Male
Male flowers subsessile; stamens up to c. 30 in several whorls on a domed torus around the pistillode; filaments short or absent; anthers oblong, extrorse, 2-locular, dehiscing longitudinally, connective produced apically into 2 spines and a central projection as in perianth lobes, immature anthers resembling perianth lobes, margins 1–3 spined; mature anthers detach and float to the water-surface where they dehisce and shed pollen on to plants below
Female
Female flowers sessile or shortly pedicellate; staminodes absent; ovary superior, sessile, ovoid, tapering into a long style; ovule 1, pendulous
Fruits
Fruit a nut, ovoid or ellipsoid, often warty and basally-spined, style ± persistent, spinose
Seeds
Embryo straight, endosperm absent
[NTK]

Every, J.L.R. (2010). Neotropical Ceratophyllaceae.

Morphology
Description

Submersed aquatic, rootless, glabrous herbs. Leaves whorled , simple , finely divided (often dichotomously branched), lobes often toothed, petiole inconspicuous or lacking. Inflorescences extra- axillary and alternating with leaves, spikes or racemes. Flowers solitary, unisexual, monoecious , actinomorphic , pedicels short or flowers sessile , bracts foliaceous ; calyx of (7)9-12(15) toothed sepals; corolla lacking; stamens 3-many, spirally arranged, free of perianth , filaments short, anthers adnately fixed, dehiscing via full-length slits; ovary superior , monomerous, style 1, persistent , spiny , occasionally bifid. Fruits achenes, papillose , spiny or smooth. Seeds 1, tiny.

Distribution
Distribution in the Neotropics
  • Throughout the Neotropics in non-marine aquatic habitats.
General Description
Number of genera
  • One genus Ceratophyllum L. with three of the six cosmopolitan species: C. demersum L., C. submersum L. and C. muricatum (Cham.) occurring in the Neotropics.
General notes

 

Notes on delimitation
  • Recently placed in an order of its own - the Ceratopyllales with molecular evidence positioning Ceratophyllaceae as probable sister to eudicots (APG III, 2009).
  • The development and complicated make-up of the perianth has led the family to be compared with the ANITA clade (excluding Nymphales).
Diagnostic
Useful tips for generic identification
  • Native and naturalizing; has become a problem weed harbouring vectors of diseases threatening human health and choking the waterways in which they inhabit.
Distinguishing characters (always present)
  • Aquatic herbs.
  • Leaves in whorls of 3-10.
  • Roots lacking.
  • Stamens ca. 3-45.
  • Styles persistent on fruits.
Key differences from similar families
  • Distinguished from Myriophyllum L. (Haloragaceae) by the branched leaves and achenefruit.
Literature
Important literature Akitoshi, I., Akiko, S. and Hideaki, O.2003. Floral development and phyllotactic variation in Ceratophyllumdemersum (Ceratophyllaceae). American Journal of Botany 90(8):1124-1130.APG III. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society 161(3): 105-121.Campbell, L. M. 2004. In: Smith, N., Mori, S. A., Henderson, A., Stevenson, D. W. and Heald, S. V. (eds). Flowering Plants of the Neotropics. Pp. 96-7. The New York Botanical Garden, Princeton University Press, Princeton.Les, D. 1993. In: Kubitzki, K., Rohwer, J. G., & Bittrich, V. (eds.), The Families and Genera of Vascular Plants vol. II. Flowering Plants: Dicotyledons, Magnoliid, Hamamelid and Caryophyllid Families. Pp 246-250. Springer Verlag, Berlin.Mabberley, D. J. 2008. Mabberley's Plant-book. 3rd ed. Pp. 168-9. Cambridge University Press, Cambridge.Stevens, P. F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/. Watson, L. and Dallwitz, M.J. (1992 onwards). The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version 3rd March 2009. http://delta-intkey.com.

Images

Ceratophyllaceae Gray appears in other Kew resources:

First published in Nat. Arr. Brit. Pl. 2: 395, 554. 1822 [10 Jan 1822] (1822)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Flora Zambesiaca
Flora Zambesiaca
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of West Tropical Africa
Flora of West Tropical Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
http://creativecommons.org/licenses/by/3.0