Xanthium strumariumL.

rough cocklebur

WFO wfo-0000082132 Accepted WFO 2026-06 7 photographs CC0 / CC BY

Plate 1 figs. a–g

Xanthium strumarium, photographed by Vasily Reinkymov
fig. a Vasily Reinkymov, CC0 1.0 / 2022-05-29 / obs. 201738111
Xanthium strumarium, photographed by Mark Apgar
fig. b Mark Apgar, CC BY 4.0 / obs. 205646808
Xanthium strumarium, photographed by Daniel Dias
fig. c Daniel Dias, CC BY-SA 4.0 / obs. 201388966
Xanthium strumarium, photographed by Haneesh K M
fig. d Haneesh K M, CC0 1.0 / obs. 195978733
Xanthium strumarium, photographed by ferferrari
fig. e ferferrari, CC0 1.0 / obs. 194146449
Xanthium strumarium, photographed by Ken-ichi Ueda
fig. f Ken-ichi Ueda, CC BY 4.0 / obs. 197676887
Xanthium strumarium, photographed by Benjamin Fredlund
fig. g Benjamin Fredlund, CC BY 4.0 / obs. 195030185

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.

Flowering n = 220 observations

Peak flowering in Sep, from 220 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 124 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.

  • Xanthium abyssinicum Wallr.
  • Xanthium acerosum Greene
  • Xanthium acutilobum Millsp. & Sherff
  • Xanthium acutum Greene
  • Xanthium affine Greene
  • Xanthium americanum Walter
  • Xanthium americanum Walt.
  • Xanthium antiquorum Wallr.
  • Xanthium arcuatum Millsp. & Sherff
  • Xanthium arenarium Lasch
  • Xanthium aridum H.St.John
  • Xanthium australe Millsp. & Sherff
  • Xanthium barcinonense Sennen
  • Xanthium brasilicum Vell.
  • Xanthium brevirostre Hochst.
  • Xanthium brevirostre Wallr.
  • Xanthium bubalocarpon Bush
  • Xanthium californicum Greene
  • Xanthium californicum var. californicum
  • Xanthium californicum var. rotundifolium Widder
  • Xanthium calvum Millsp. & Sherff
  • Xanthium campestre Greene
  • Xanthium cavanillesii Schouw
  • Xanthium cavanillesii var. cavanillesii

and 100 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.

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.