1. Cabombaceae Rich. ex A.Rich.

    1. This family is accepted.

[FTEA]

Cabombaceae, B. Verdcourt. Flora of Tropical East Africa. 1971

Habit
Aquatic herbs with perennial sympodial rhizomes; stems long and slender, coated with mucilage
Leaves
Leaves alternate, the floating ones peltate, the submerged ones finely divided or absent
Flowers
Flowers rather small, hermaphrodite, axillary, solitary and regular
Calyx
Sepals 3, petaloid
Corolla
Petals 3, hypogynous
Androecium
Stamens 3–18, with extrorse anthers dehiscing longitudinally
Gynoecium
Carpels 2–18, completely free, with a simple narrow stigma but very reduced style; ovules 1–3, parietal, pendulous, anatropous
Fruits
Fruiting carpels indehiscent, 1–3-seeded
Seeds
Seeds with fleshy endosperm and perisperm but no aril
[FZ]

Cabombaceae, H. Wild. Flora Zambesiaca 1:1. 1960

Habit
Aquatic herbs with perennial rhizomes; stems coated with mucilage
Leaves
Leaves alternate, floating leaves peltate, sometimes with finely dissected submerged leaves in addition
Flowers
Flowers axillary, solitary, actinomorphic
Calyx
Sepals 3
Corolla
Petals 3, hypogynous
Androecium
Stamens 3–18; anthers extrorse, opening lengthwise
Gynoecium
Carpels 2–18, free; style very short or absent but with an attenuated, entire stigma; ovules 1–3, pendulous, parietal
Fruits
Fruiting carpels indehiscent
Seeds
Seeds 1–3 with a fleshy endosperm
[NTK]

Aona, L.Y.S. (2009). Neotropical Cabombaceae.

Morphology
Description

Perennial aquatic glabrous plants, rarely annual ; rhizome elongated, fixed to the substrate, stems elongated and submersed to distally floating. Leaves simple , petiolate , heterophyllous, floating, peltate , narrowly elliptic to broadly ovate , the submerse ones (only in Cabomba Aubl.) dissected , palmate ; stipules absent. Flowers on long pedicels, opening above the water, solitary, hermaphrodite , symmetry radial, hypogynous, tepals 6, white, pink, purple or yellow, the inner tepals (petals) with nectariferous auricles near the base; stamens 3-36, free , filaments flattened, anthers oblong , basifixed, with two thecae, extrorse with longitudinal dehiscence, carpels (1- )2-4(-18), free , ovules (1-)2-5, placentation laminar. Fruit achene -like, coriaceous , indehiscent ; seeds 1-5 per fruit , embryo small, endosperm reduced, perisperm abundant.

Distribution
Distribution in the Neotropics

Two genera:

  • Cabomba (c. 5 species, widely distributed from the USA to Argentina), leaves heterophyllous, inner tepals bearing nectaries.
  • Brasenia schreberi J.F.Gmel., a wind pollinated species with reduced flowers, distributed worldwide and cultivated for its edible shoots.
Diagnostic
Other important characters
  • Petals (inner tepals) with auricular nectaries.
  • Placentation laminar.
Distinguishing characters (always present)
  • Cabombaceae are rather small-flowered 'waterlilies', with few ovules or seeds in each carpel; they have floating stems and all their flower parts are free (Stevens 2008).
Key differences from similar families

Cabombaceae is closely related to the true 'waterlilies', Nymphaeaceae, sharing with it several characters e.g:

  • Stem rhizomatous.
  • Leaves involute.
  • Leaves peltate.
  • Secondary veinspalmate, actinodromous, festoon brochidodromous.
  • Actinodromous.
  • Festoon brochidodromous.
  • Margin toothed or entire.
  • Flowers are single along the stem.

However, in Cabombaceae the flowers are trimerous, with 6 tepals (vs. sepals 4-6(-12) and petals 6-70 in Nympheaceae), and leaves may be heterophyllous.

Useful tips for generic identification
  • Brasenia Schreb. is wind pollinated.
  • Cabomba has paired nectaries on its inner tepals and is pollinated by insects (Stevens 2008).
Notable genera and distinguishing features

See above

General Description
Number of genera

See above.

Notes on delimitation
  • Cabombaceae is in the order Nympheales together with Nymphaeaceae and Hydatellaceae.
  • Saarela et al. (2007) suggest a few additional possible synapomorphies for Nymphaeales, such as hydrolysable tannins which in this group (e.g. in Nuphar Sm.) are different from those found elsewhere (Gottlieb et al. 1993; Ishimatsu et al. 1989) - although of course Hydatellaceae are a poorly known group.
Status
  • Both genera are widely distributed and native. Species of the genus Cabomba are often used as aquarium plants.
Literature
Important literature

FERES, F. & AMARAL, M.C.E. 2003. Cabombaceae. In Wanderley, M. G. L., Shepherd, G. J. & Giulietti, A. M. (Eds.). Flora Fanerogâmica do Estado de São Paulo. Vol. 3. São Carlos, Editora RiMA. pp: 09-11.

GOTTLIEB, O., R., Kaplan, M. A. C., & Kubitzki, K. 1993. A suggested role of galloyl esters in the evolution of dicotyledons. Taxon 42: 539-552.

ISHIMATSU, M., Tanaka, T., Nonaka, G., Nishioka, I., Nishizawa, M., & Yamagishi, T. 1989. Tannins and related compounds. LXXIX. Isolation and characterisation of novel dimeric and trimeric hydrolyzable tannins, nuphrins C, D, E and F, from Nuphar japonicum DC. Chem. Pharmac. Bull. 37: 1735-1743.

ORGAARD, M. 1991. The genus Cabomba (Cabombaceae) - a taxonomic study. Nordic J. Bot. 11(2): 179-203.

SAARELA, J. M., Rai, H. S., Doyle, J. A., Endress, P. K., Mathews, S., Marchant, A. D., Briggs, B., & Graham, S. W. 2007. Hydatellaceae identified as a new branch near the base of the angiosperm phylogenetic tree. Nature 446: 312-315.

STEVENS, P. F. 2008. Angiosperm Phylogeny Website. Version 9, June 2008 [and more or less continuously updated since]. http://www.mobot.org/MOBOT/research/APweb/.

Images

Cabombaceae Rich. ex A.Rich. appears in other Kew resources:

First published in Dict. Class. Hist. Nat. [Bory] 2: 608. 1822 [31 Dec 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

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2018. 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