Emex spinosa

Emex spinosa by Ron Vanderhoff
Photo by Ron Vanderhoff

Synonyms: Rumex spinosus

Common names: devil's thorn; spiny threecornerjack

Emex spinosa (spiny emex, devil’s-thorn) is an annual (family Polygonaceae) found on California’s south coast. This Mediterranean native is not yet common in California, but it is spreading rapidly and is known to crowd out native species. It frequently infests disturbed areas, especially in coastal habitats. Emex spinosa’s spiny seed pods stick to people and animals, so it spreads quickly along trails and then into undisturbed areas.

Cal-IPC Rating: Moderate — Alert

Cal-IPC Assessment

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Weed RIC Management Notes

  • Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

There are no Symposium presentations associated with this species yet.

Other Emex spinosa Information

  • CalPhotos - Images of plants taken mostly in California.
  • Calflora - See the distribution of this species on Calflora's map of California.
  • CalWeedMapper - Distribution information with ability to determine regional priorities.
  • Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
  • USDA PLANTS Database - Federal database with information on identification and distribution, and links to websites in individual states.