Sagittaria montevidensisCham. & Schltdl.

giant arrowhead

WFO wfo-0000738022 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Sagittaria montevidensis, photographed by Hunter Hammil
fig. a Hunter Hammil, CC BY 4.0 / 2021-10-01 / obs. 160948861
Sagittaria montevidensis, photographed by Tom Field
fig. b Tom Field, CC BY 4.0 / obs. 91448976
Sagittaria montevidensis, photographed by Brian Dickerson
fig. c Brian Dickerson, CC0 1.0 / obs. 90968306
Sagittaria montevidensis, photographed by Kevin Faccenda
fig. d Kevin Faccenda, CC BY 4.0 / obs. 102594661
Sagittaria montevidensis, photographed by Sam Kieschnick
fig. e Sam Kieschnick, CC BY 4.0 / obs. 2454188
Sagittaria montevidensis, photographed by L. K. Holt
fig. f L. K. Holt, CC BY 4.0 / obs. 10618418
Sagittaria montevidensis, photographed by Andy Jordan
fig. g Andy Jordan, CC BY 4.0 / obs. 167752298
Sagittaria montevidensis, photographed by kent ozment
fig. h kent ozment, CC0 1.0 / obs. 163276227

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 43 botanical countries

Regions where Sagittaria montevidensis is native: Alabama, Arkansas, California, Colorado, Delaware, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Mexico Northeast, Mexico Northwest, Mexico Southeast, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Mexico, North Carolina, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Virginia, West Virginia, Wisconsin, Argentina Northeast, Argentina Northwest, Bolivia, Brazil South, Brazil Southeast, Chile Central, Chile South, Ecuador, Paraguay, Peru, Uruguay AlabamaArkansasCaliforniaColoradoGeorgiaIllinoisIndianaIowaKansasKentuckyLouisianaMarylandMexico NortheastMexico NorthwestMexico SoutheastMichiganMinnesotaMississippiMissouriNebraskaNew MexicoNorth CarolinaOhioOklahomaSouth CarolinaSouth DakotaTennesseeTexasVirginiaWest VirginiaWisconsinArgentina NortheastArgentina NorthwestBoliviaBrazil SouthBrazil SoutheastChile CentralChile SouthEcuadorParaguayPeruUruguay Delaware
Native distribution of Sagittaria montevidensis, 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
Alabama ALA NORTHERN AMERICA
Arkansas ARK
California CAL
Colorado COL
Delaware DEL
Georgia GEO
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Kentucky KTY
Louisiana LOU
Maryland MRY
Mexico Northeast MXE
Mexico Northwest MXN
Mexico Southeast MXT
Michigan MIC
Minnesota MIN
Mississippi MSI
Missouri MSO
Nebraska NEB
New Mexico NWM
North Carolina NCA
Ohio OHI
Oklahoma OKL
South Carolina SCA
South Dakota SDA
Tennessee TEN
Texas TEX
Virginia VRG
West Virginia WVA
Wisconsin WIS
Argentina Northeast AGE SOUTHERN AMERICA
Argentina Northwest AGW
Bolivia BOL
Brazil South BZS
Brazil Southeast BZL
Chile Central CLC
Chile South CLS
Ecuador ECU
Paraguay PAR
Peru PER
Uruguay URU

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 471 in flower of 535 examined

Peak flowering in Jan. Each bar is the share of Sagittaria montevidensis 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. 471 of 535 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 43 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.

  • Lophiocarpus calycinus (Engelm.) Micheli
  • Lophotocarpus californicus J.G.Sm.
  • Lophotocarpus calycinus (Engelm.) J.G.Sm.
  • Lophotocarpus calycinus f. depauperatus (J.G.Sm.) Fernald
  • Lophotocarpus calycinus f. fluitans (Engelm.) Steyerm.
  • Lophotocarpus calycinus f. maximus (Engelm.) Fernald
  • Lophotocarpus calycinus var. maximus (Engelm.) B.L.Rob.
  • Lophotocarpus calycinus var. spongiosus Fassett
  • Lophotocarpus depauperatus J.G.Sm.
  • Lophotocarpus fluitans J.G.Sm.
  • Lophotocarpus spathulata J.G.Sm.
  • Lophotocarpus spatulatus J.G.Sm.
  • Lophotocarpus spongiosus J.G.Sm.
  • Lophotocarpus spongiosus f. laminatus Fernald
  • Sagittaria alismifolia Phil. ex Micheli
  • Sagittaria andina Phil.
  • Sagittaria calycina Engelm.
  • Sagittaria calycina Engelm. ex Torr.
  • Sagittaria calycina var. depauperata Engelm. & J.G.Sm.
  • Sagittaria calycina var. fluitans Engelm.
  • Sagittaria calycina var. grandis Engelm.
  • Sagittaria calycina var. maxima Engelm.
  • Sagittaria calycina var. media Engelm.
  • Sagittaria calycina var. spongiosa Engelm.

and 19 more.

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.