1. Haloragaceae R.Br.

    1. This family is accepted.


Haloragaceae, E. J. Mendes. Flora Zambesiaca 4. 1978

Herbs or undershrubs, often aquatic, monoecious, polygamous or dioecious
Leaves alternate, opposite or verticillate, pinnately or palmately nerved, sometimes very large, the submerged ones often much divided; stipules absent
Inflorescences axillary or terminal, the flowers usually small, arranged in cymes, fascicles, racemes, panicles or spikes, or solitary; bracts often present
Calyx-tube short, adnate to the ovary; calyx-lobes 2–4, mostly valvate and persistent, or absent
Petals 2–4, valvate or ± imbricate, or absent
Stamens 2, 3, 4 or 8, rarely 1 or absent; anthers basifixed, 2-celled, dehiscing lengthwise; filaments mostly filiform
Gynoecium 1–4-locular; ovules 1 in each loculus, pendulous from the apex; styles 1–4 or absent; stigmas papillose or plumose
Fruit a nutlet, indehiscent or breaking up into 2 or 4 single-seeded mericarps, or a drupe
Seeds with abundant fleshy or oily endosperm

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

Herbs or undershrubs, often aquatic; leaves alternate, opposite or verticillate, sometimes very large, the submersed ones often much divided; stipules absent
Flowers hermaphrodite or unisexual, solitary to paniculate or corymbose, often very small
Calyx-tube adnate to the ovary; lobes 2–4 or absent
Petals 3–4 or absent, valvate or slightly imbricate
Stamens 2–8, rarely 1, large; anther basifixed, 2-celled, opening lengthwise
Ovary inferior, 1–4-celled; styles 1–4; ovules as many as the styles, pendulous from the apex of the cells
Fruit small, a nut or drupe, sometimes winged, indehiscent or rarely breaking up into cocci
Seeds pendulous, with copious endosperm and straight fairly large (rarely small) embryo

Every, J.L.R. (2009). Neotropical Haloragaceae.


Herbs, perennial or rarely annual (Myriophyllum L.), aquatic or amphibious, not free -floating, with adventitious nodal roots , exstipulate , with 1(-3) deciduous pseudostipules (hydathodes) present in leaf axils of Myriophyllum. Leaves heterophyllous (Proserpinaca L. and Myriophyllum), with submerged and emergent leaves differing, opposite, alternate , spiraling or whorled , entire or finely pinnately dissected , sometimes serrate and simple , shortly petiolate , subsessile or sessile . Inflorescence axillary , thyrses lacking terminal flowers (Proserpinaca) or racemes with female flowers in lower part and males in the upper (Myriophyllum) or 1-11-flowered fascicles, sometimes of either bisexual and female flowers or made up of both male and female (Laurembergia P. J. Bergius); bracteoles 2. Flowers, very small, actinomorphic , hermaphroditic, polygamous or unisexual and monoecious , epigynous , (2-)4- merous or 3- merous (Proserpinaca) sessile or pedicillate; sepals valvate , forming a tube, persistent (mostly absent in female Myriophyllum; petals absent or rudimentary and free , imbricate ; stamens (1-)4 or 8 (3 in Proserpinaca), filaments short, slender; anthers basifixed, dehiscing by slits; gynoecium (-2)4-carpellate; ovary inferior (-1)4-locular, sometimes becoming unilocular (Laurembergia), stylodia 1 per carpel , feathery, stigma capitate . Fruit non- fleshy , indehiscent or an ornamented schizocarp . Seeds 1-3.

Distribution in the Neotropics
  • Centre of diversity in Australia with c. 60% of species (Moody 2007).
  • Three Neotropical genera grow in slow moving water or in marshy, littoral habitats.
  • Some species are found at greater than 3,000 m.
  • Myriophyllum is the most speciose genus of the family and has a cosmopolitan distribution and can be found in eastern South America, the West Indies and Central America.
  • Proserpinaca has c. 3 species and occurs from North America through Mexico into Guatemala and the West Indies.
  • Laurembergia is a pantropical genus (excluding Australia) with c. 4 spp. and widespread in the Neotropics particularly eastern South America.
Distinguishing characters (always present)
  • Aquatic or amphibian herbs.
  • Axillaryinflorescence.
  • Small flowers with radial symmetry.
  • Anthers basifixed, dehiscing by longitudinal slits.
  • Ovary inferior.
  • Styles distinct and feathery.
  • Stigmacapitate.
  • Fruit non-fleshy.
Other important characters
  • 2 bracteoles subtending the flower, occasionally caducous.
  • Petals yellow, blue-green or red-purple.
Key differences from similar families

The features listed are not present in the Haloragaceae:

  • Gunneraceae: petiolate (often long), zygomorphic flowers, fleshydrupaceous fruits or leathery dehiscent fruits.
  • Penthoraceae: superiorovary, many seeds.
  • Tertracarpaeaceae: superiorovary, free carpels, many seeds, endemic to Tasmania.
Notable genera and distinguishing features


  • Alternate heterophyllous leaves.
  • Inflorescence solitary or in dichasia of up to 3 flowers per axil.
  • Flowers hermaphroditic.
  • Fruit 3-seeded nutlet.


  • Whorled heterophyllous leaves.
  • Flowers frequently unisexual.
  • Sepals less than half the length of the petals (frequently absent).
  • Fruit schizocarpic, ornamented and splitting at maturity into 2-4 mericarps.


  • Leaves subwhorled, opposite or alternate, not heterophyllous.
  • Flowers unisexual in dichasia, the distal positions occupied by male or hermaphroditic flowers which stand out on a long pedicel from the almost sessile female flowers.
  • 8 stamens in 2 whorls with the outer fertile whorl alternating with the sepals.
  • The ovary initially 4-loculate, becoming 1-4-loculate through the collapse of the columella.
  • One-seeded fruit with variable structure.
General Description
  • Native.
  • Myriophyllum aquticum (Vell.) Verdc. and M. spicatum L. are invasive weeds.
General notes
  • Anemophilous.
  • Cultivated in aquaria and sometimes as pond plants.
Number of genera
  • Three Neotropical representatives of the eight mainly antipodean genera.
Notes on delimitation
  • Sister to the monogeneric Penthoraceae which does not occur in the Neotropics (Stevens, 2001 onwards).
  • Placed within the Saxifragales (APG2, 2003).
  • Removed from the Myrtales by Takhtajan (1997).
  • Long associated with Gunneraceae.
Important literature

APG 2. 2003. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. Botanical Journal of the Linnean Society. 141: 399-436.

Brummitt, R.K. In Heywood, V.H., Brummitt, R.K., Culham, A. and Seberg, O. (eds). 2007. Flowering Plant Families of the World, pp. 162-3. Royal Botanic Gardens, Kew, Richmond.

Kubitzki, K. 2007. Haloragaceae. In: Kubitzki, K. (ed.). Families and genera of vascular plants. Volume 9. Flowering plants. Eudicots.pp.185-190. Springer-Verlag, Berlin.

Maas, P.J.M. & Westra, L.Y. Th. 2005. Neotropical Plant Families. 3rd ed, p.148. A.R.G. Gantner Verlag K.G., Ruggell.

Mabberley, D. J. 2008. Mabberley's Plant-book. 3rd ed. p. 387 Cambridge University Press, Cambridge.

Moody, M. L. & Les, D. H. 2007. Phylogenetic systematics and character evolution in the angiosperm family Haloragaceae. American Journal of Botany 94(12): 2005-2025.

Orchard, A. E. 1981. A revision of South American Myriophyllum (Haloragaceae), and its repercussions on some Australian and North American species. Brunonia 41: 27-65.

Smith, N. & Stevenson, D.W. 2004.  Haloragaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds). Flowering Plants of the Neotropics. pp.178-179. The New York Botanical Garden, Princeton University Press, Princeton.

Stevens, P.F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/.

Takhtajan, A. 1997. Diversity and Classification of Flowering Plants. Columbia University Press, New York.

Watson, L. & Dallwitz, M.J. (1992 onwards).  The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version 3rd March 2009. http://delta-intkey.com.


Haloragaceae, R. Boutique (Jardin botanique national de Belgique) and B. Verdcourt (Royal Botanic Gardens, Kew). Flora of Tropical East Africa. 1973

Fruit a nutlet or drupe, bluntly angular, ribbed or winged with 1–4 1-seeded locules or divided in 2 or 4 1-seeded cocci
Seeds with abundant fleshy albumen
Aquatic or terrestrial herbs or subshrubs with hermaphrodite, monoecious or dioecious flowers
Leaves usually exstipulate, alternate, opposite, whorled or all radical, sometimes very small, the blades simple, entire or ± divided especially in the case of submerged leaves
Inflorescences axillary or terminal, the flowers in cymes, fascicles, racemes, panicles, spikes or solitary; bracts often present
Flowers often bracteolate, usually small, regular
Calyx with the tube adnate to the ovary; lobes 2–4, valvate, sometimes rudimentary or absent
Petals 2(–3)–4, valvate or slightly imbricate-contorted, or sometimes absent
Stems (1–)2–8; filaments long or short; anthers basifixed, 2-thecous, dehiscing by lateral slits
Ovary inferior, rounded or angular to winged, 1–4-locular; locules 1-ovulate; ovule apical, pendulous, anatropous; styles 1–4, free or absent; stigmas papillate or plumose


Haloragaceae R.Br. appears in other Kew resources:

First published in Voy. Terra Austral. 2: 549. 1814 [19 Jul 1814] (1814)

Accepted by

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


Flora Zambesiaca
Flora Zambesiaca

Flora of Tropical East Africa
Flora of Tropical East Africa

Flora of West Tropical Africa
Flora of West Tropical Africa

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

Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.