Xanthium strumariumLour.

rough cocklebur

WFO wfo-0000008369 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h

Xanthium strumarium, photographed by Mark Apgar
fig. a Mark Apgar, CC BY 4.0 / 2022-06-12 / obs. 205646808
Xanthium strumarium, photographed by Vasily Reinkymov
fig. b Vasily Reinkymov, CC0 1.0 / obs. 201738111
Xanthium strumarium, photographed by Haneesh K M
fig. c Haneesh K M, CC0 1.0 / obs. 195978733
Xanthium strumarium, photographed by Daniel Dias
fig. d Daniel Dias, CC BY-SA 4.0 / obs. 201388966
Xanthium strumarium, photographed by Ken-ichi Ueda
fig. e Ken-ichi Ueda, CC BY 4.0 / obs. 197676887
Xanthium strumarium, photographed by Benjamin Fredlund
fig. f Benjamin Fredlund, CC BY 4.0 / obs. 195030185
Xanthium strumarium, photographed by ferferrari
fig. g ferferrari, CC0 1.0 / obs. 194146449
Xanthium strumarium, photographed by Udi Oron אודי אורון
fig. h Udi Oron אודי אורון, CC0 1.0 / obs. 194706852

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 34 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 antiquorum Wallr.
  • Xanthium australe Millsp. & Sherff
  • Xanthium brasilicum Vell.
  • Xanthium californicum Greene
  • Xanthium californicum var. californicum
  • Xanthium cavanillesii Schouw
  • Xanthium cavanillesii var. cavanillesii
  • Xanthium echinatum subsp. italicum (Moretti) O.Bolòs & Vigo
  • Xanthium echinatum var. cavanillesii (Schouw) O.Bolòs & Vigo
  • Xanthium echinatum var. italicum (Moretti) O.Bolòs & Vigo
  • Xanthium indicum J.Koenig ex Roxb.
  • Xanthium italicum Moretti
  • Xanthium italicum subsp. italicum
  • Xanthium italicum var. italicum
  • Xanthium macrocarpum subsp. macrocarpum
  • Xanthium macrocarpum var. italicum (Moretti) Nyman
  • Xanthium macrocarpum var. macrocarpum
  • Xanthium orientale f. orientale
  • Xanthium orientale subsp. californicum (Greene) Greuter
  • Xanthium orientale subsp. italicum (Moretti) Greuter
  • Xanthium orientale subsp. orientale
  • Xanthium orientale subsp. saccharatum (Wallr.) B.Bock
  • Xanthium orientale var. orientale
  • Xanthium saccharatum Wallr.

and 10 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.