Iva annuaL.

Sumpweed

WFO wfo-0000005612 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Iva annua, photographed by Ryan Watson
fig. a Ryan Watson, CC BY 4.0 / 2021-10-09 / obs. 162477809
Iva annua, photographed by saltyhiker
fig. b saltyhiker, CC BY 4.0 / obs. 159707672
Iva annua, photographed by Sam Kieschnick
fig. c Sam Kieschnick, CC BY 4.0 / obs. 158024291
Iva annua, photographed by Thomas Koffel
fig. d Thomas Koffel, CC BY 4.0 / obs. 155515766
Iva annua, photographed by Annika Lindqvist
fig. e Annika Lindqvist, CC BY 4.0 / obs. 159127347
Iva annua, photographed by Robert Hoard
fig. f Robert Hoard, CC0 1.0 / obs. 162338199
Iva annua, photographed by Robert Hoard
fig. g Robert Hoard, CC0 1.0 / obs. 157571688
Iva annua, photographed by Robert Hoard
fig. h Robert Hoard, CC0 1.0 / obs. 153520281

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.

Confused withby our own model

These are not lookalikes we guessed at. Each one is a species our identification model genuinely mistook for this plant, and how many times. The error rate is published.

Flowering n = 78 observations

Peak flowering in Sep, from 78 community-annotated observations worldwide. This is a global aggregate, not a forecast for your garden: the same species flowers on different dates in different hemispheres, and citizen-science records cluster near cities, at weekends, and in spring. Where a species has fewer than 30 annotated records we do not draw this chart at all.

Also published as 8 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.

  • Ambrosia pitcheri Torr. ex Hook.
  • Iva annua var. annua
  • Iva annua var. caudata (Small) R.C.Jacks.
  • Iva annua var. macrocarpa (S.F.Blake) R.C.Jacks.
  • Iva caudata Small
  • Iva ciliata Willd.
  • Iva ciliata var. ciliata
  • Iva ciliata var. macrocarpa S.F.Blake

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.

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