Apium prostratumLabill. ex Vent.

Sea Celeryprostrate marshwort

WFO wfo-0000540700 Accepted WFO 2026-06 8 photographs CC BY

Plate 1 figs. a–h · 8 separate observations

Apium prostratum, photographed by Joe Dillon
fig. a Joe Dillon, CC BY 4.0 / 2022-06-05 / obs. 203786322
Apium prostratum, photographed by Joe Dillon
fig. b Joe Dillon, CC BY 4.0 / obs. 203786553
Apium prostratum, photographed by Joe Dillon
fig. c Joe Dillon, CC BY 4.0 / obs. 203786334
Apium prostratum, photographed by Shaun
fig. d Shaun, CC BY 4.0 / obs. 192112709
Apium prostratum, photographed by Joe Dillon
fig. e Joe Dillon, CC BY 4.0 / obs. 191472875
Apium prostratum, photographed by Joe Dillon
fig. f Joe Dillon, CC BY 4.0 / obs. 191479352
Apium prostratum, photographed by Joe Dillon
fig. g Joe Dillon, CC BY 4.0 / obs. 191479222
Apium prostratum, photographed by Joe Dillon
fig. h Joe Dillon, CC BY 4.0 / obs. 191479767

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 20 botanical countries

Regions where Apium prostratum is native: Cape Provinces, Namibia, Antipodean Is., Chatham Is., Kermadec Is., New South Wales, New Zealand North, New Zealand South, Norfolk Is., Queensland, South Australia, Tasmania, Victoria, Western Australia, Easter Is., Pitcairn Is., Tubuai Is., Argentina Northeast, Brazil South, Uruguay Cape ProvincesNamibiaNew South WalesNew Zealand NorthNew Zealand SouthQueenslandSouth AustraliaTasmaniaVictoriaWestern AustraliaArgentina NortheastBrazil SouthUruguay Antipodean Is.Chatham Is.Kermadec Is.Norfolk Is.Pitcairn Is.Tubuai Is.
Native distribution of Apium prostratum, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Antipodean Is. ATP AUSTRALASIA
Chatham Is. CTM
Kermadec Is. KER
New South Wales NSW
New Zealand North NZN
New Zealand South NZS
Norfolk Is. NFK
Queensland QLD
South Australia SOA
Tasmania TAS
Victoria VIC
Western Australia WAU
Easter Is. EAS PACIFIC
Pitcairn Is. PIT
Tubuai Is. TUB
Argentina Northeast AGE SOUTHERN AMERICA
Brazil South BZS
Uruguay URU
Cape Provinces CPP AFRICA
Namibia NAM

Not drawn on the map: Easter Is.. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 341 in flower of 573 examined

Peak flowering in Dec. Each bar is the share of Apium prostratum observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 341 of 573 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 9 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Apium australe var. angustisectum H.Wolff
  • Apium dunicola Pontiroli
  • Apium filiforme Hook.
  • Apium prostratum var. maritimum Domin
  • Helosciadium australe Bunge
  • Helosciadium prostratum Bunge
  • Petroselinum filiforme A.Rich.
  • Petroselinum prostratum DC.
  • Wydleria humilis Phil.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.