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  • Ruppiaceae Horan.

This family is accepted.
Ruppia maritima


Haigh, A. (2009). Neotropical Ruppiaceae.


Habit : aquatic herbs, submersed, mostly annual (occasionally surviving winter as underground rhizome ). Leaves alternate , simple , sessile , sheathed at base, the sheaths fused for entire length; ligule absent; blades linear , the margins entire , except at apex , the apex irregularly serrate ; venation of midrib only. Inflorescences terminal , 1- few-flowered spikes, the spikes first enclosed by 2 sub-opposite foliage leaves; peduncle varying in length (by species), projecting inflorescence to water surface (where pollination occurs). Flowers actinomorphic , bisexual ; perianth absent; androecium of 2 sessile stamens, the anthers dehiscing by longitudinal slits, each bearing a broad connective with a dorsiventral outgrowth; gynoecium apocarpous, the ovaries superior , the carpels (2-)4(-16), stalked, the stigma sessile or nearly so; placentation marginal distally, the ovule 1 per carpel , ± pendulous near apex of carpel . Fruits drupes, nearly spherical, stalked, the endocarp rigid; seeds 1 per fruit , the seed coat permanently attached to endocarp .

General Description
Notes on delimitation
  • Placed in the Alismatales, its closest relative is Cymodoceaceae.
General notes
  • Ruppiaceae are useful in stabilizing substrates and removing suspended particles from the water column.
  • Native.
Distribution in the Neotropics
  • A subcosmopolitan family of 1 genus (Ruppia L.) and 1-12 species depending on taxonomic framework, with about 1-7 species native to fresh and brackish waters of coastal as well as inland Neotropics.
Distinguishing characters (always present)
  • Submersed aquatic herbs.
  • Leaves alternate, simple, sessile, sheathed at base.
  • Flowers actinomorphic, bisexual; perianth absent; stamens 2, sessile; gynoecium apocarpous.
  • Fruits drupes.
Important literature

Haynes, R.R., 2004. Ruppiaceae. Pp. 479-480. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. & Heald, S.V. (eds.). Flowering Plants of the Neotropics. New York Botanical Garden, Princeton University Press, Princeton.

Haynes, R.R., Holm-Nielsen,L.B. and Les,D.H. 1998. Ruppiaceae. In: K. Kubitzki (ed.), The families and genera of vascular plants 4: 445-448. Springer Verlag, Berlin.

Novelo, R.A., 1991. Ruppiadidymia (Potamogetonaceae) en México y las Antillas. An. Inst. Biol. Univ. Nac. Auton. Méx. Ser. Bot. 62:173-180.


Ruppiaceae, F.N. Hepper. Flora of West Tropical Africa 3:1. 1968

Morphology General Habit
Aquatic herbs of saline marshes
Morphology Leaves
Leaves opposite or alternate, linear or setaceous, sheathing at the base
Morphology Reproductive morphology Flowers
Flowers hermaphrodite, small, in terminal spikes at first enclosed by the sheathing base of the leaves, at length much elongated; bracts and perianth absent
Morphology Reproductive morphology Flowers Androecium
Stamens 2; filaments short, broad; anthers extrorse, loculi reniform and separated by the connective
Morphology Reproductive morphology Flowers Gynoecium
Ovule solitary, pendulous Carpels 4 or more, free, stigmas peltate or umbonate
Morphology Reproductive morphology Fruits
Fruits long-stipitate with spirally twisted stalks, indehiscent
Morphology Reproductive morphology Seeds
Seeds pendulous, without endosperm


Ruppiaceae, K.A. Lye (Agricultural University of Norway). Flora of Tropical East Africa. 1989

Morphology General Habit
Submerged monoecious glabrous aquatic herbs of alkaline or brackish water, sometimes in sea-water
Vegetative Multiplication Rhizomes
Rhizome thin, matted, perennial, rooted in the substrate
Morphology Stem
Stem slender, erect, branching freely, monopodial below, sympodial above
Morphology Leaves
Leaves alternate or opposite; blade simple, linear or setaceous, with a single midvein; sheath wide, distally open
Morphology Reproductive morphology Inflorescences
Inflorescence usually a 2-flowered terminal spike with the flowers inserted at unequal heights and on opposite sides of the rachis, when young concealed in the sheath of the uppermost vegetative leaf, and just exserted above the water at anthesis; peduncle short or long, sometimes spirally coiled
Morphology Reproductive morphology Flowers
Flowers bisexual, actinomorphic, protandrous, very small and inconspicuous
Morphology Reproductive morphology Flowers Perianth
Perianth absent
Morphology Reproductive morphology Flowers Androecium
Stamens 2, opposite each other; filaments very short and broad; anthers 2-thecous, extrorse, the 2 relatively large pollen-sacs divergent and well separated; pollen-grains luniform and of a unique type, buoyant
Morphology Reproductive morphology Flowers Gynoecium
Ovaries 2-8, but usually 4, free, superior, sessile at first, becoming long-stipitate in fruit; ovule solitary, pendulous, campylotropous, crassinucellar; stigma sessile, peltate, ventroapical
Morphology Reproductive morphology Fruits
Fruits ovoid-pyriform, often asymmetric, beaked drupes
Morphology Reproductive morphology Seeds
Seeds hard, without endosperm

Ruppiaceae Horan. appears in other Kew resources:

First published in Prim. Lin. Syst. Nat. 46. 1834 [2 Nov 1834] (1834)

Accepted by

  • APG IV (2016)

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 2021. Published on the Internet at and
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families.

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